Slate’s animal blog.

Jan. 29 2015 9:30 AM

Turtle Trafficking

Look for a ceramic turtle in front of the store. That’s the signal. James knows it’s the spot to score red-eared sliders.

It’s a perfectly timed endeavor. Eight minutes before closing time, James (who asked that I not use his last name) dashes into a New York Chinatown tchotchke shop—located on Mott Street, just below Canal—with a wad of cash. The boxes are waiting for him. A shopkeeper, a woman in her 70s, struggles to wrangle them from a back room obscured by a curtain and boxes of paper fans. It looks like she ought to buckle under the weight, but she manages, and when he arrives, they are ready to be moved—quickly. He hands over $200: exact change. “100 cages, too,” he says. “The good kind.” He counts out another $100, and the woman shuffles away to retrieve them.


James starts loading the haul into his sedan, idling out front on Mott. The backseat is filling with boxes. Each contains 100 live turtles.

The elderly woman sees him chatting to passersby and dashes outside, shrilly assuring people that the boxes are “just turtle food.” She’s not fooling anyone: Tiny tails and speckled shells are visible through the air holes. Plus, each cardboard container is emblazoned with the words “Live Animals.”

Back inside, below the cash register, six turtles, each the size of a peach pit, paddle in a takeout container inside a shallow woven plastic basket. The water is murky and there’s not much space to swim. Nor is there a spot to perch, a light emitting UVB rays, or a heat source keeping the water between 75 and 95 degrees—all common recommendations for turtle husbandry.

James is a consummate salesman. “I’ve never had a real job,” he boasts. “I started out selling shoes and T-shirts on the side of the street, and now I’m branching out into real estate.” But today, he’s a turtle trafficker, selling to carnivals all over the East Coast. “Kids love them,” he says. Turns out, it’s a lucrative business. He brags, “We can make as much as $7,000 in one day.”

The high demand means that he needs a lot of turtles. He drives into the city from Philadelphia every Thursday to replenish his supply.

On another evening, after James’ visit, the old woman isn’t feeling so cautious. She lounges on the steps in front of the crowded shop, openly hawking her wares. She jabs a paper fan toward potential customers and calls, “Turtles inside, turtles inside!” A mother and preteen daughter turn into the store. “How much?” they ask. There’s a rapid-fire exchange in Chinese, and then a response: “$15 for two, including the container and food.” A group of tourists fawns over the hatchlings. “I wish we could take one on the plane,” one of them squeals. There are a few takers. The mother and daughter leave a few minutes later with a turtle sloshing around in a plastic container. The girl holds the terrarium up, inspecting it. There’s no attempt to stay under the radar today.

Chinatown is the epicenter of the black-market industry devoted to trafficking the petite paddlers. In the Teenage Mutant Ninja Turtles series, set in the city, four red-eared sliders emerge from their sewage-strewn lair to fight crime and devour pizza. But in reality, there aren’t any adolescent heroes in half-shells splashing beneath the streets—contrary to the premise of the show, these terrapins are kind of the bad guys.

The non-native sliders have escaped or been introduced all along the East Coast, where they have hunkered down and beat out locals such as painted and box turtles for prime grub and nesting turf. Many are former pets discarded by their owners.

The “scourge of the sliders” is upon us, according to the New York Daily News. The critters likely migrate to New York via shipments from commercial farms in the American South, where many are bred for international export. The World Chenolian Trust estimates that nearly 31.8 million turtles were exported from the United States between 2002 and 2005 alone. Most departed from ports in New Orleans, Miami, Dallas, or Los Angeles, mainly destined for Asian food markets. More than 400 of these shipments contained at least 100,000 turtles at a time.  

The tiny turtles are illegal to sell. The FDA’s 1975 Public Health Services Act banned the peddling of turtles with shells less than 4 inches long. Like many other reptiles, these swimmers can carry salmonella bacteria and pose a health risk to kids and immunocompromised adults. These groups are most likely to contract salmonellosis, marked by nasty fever, diarrhea, and intestinal cramps. (Granted, outbreaks have also been pegged to bacteria-riddled poultry, hedgehogs, and even produce such as cantaloupe, cucumbers, alfalfa sprouts, and tomatoes, but the Centers for Disease Control and Prevention estimates that the turtle ban prevents an additional 100,000 infections per year.)

Despite the ban, red-eared sliders have been observed in the wild throughout the boroughs, and as far away as Buffalo and Rochester. On its website, the New York Turtle and Tortoise Society warns that it can’t accept any new requests to foster these creatures, saying that many thousands of sliders have been turned over. (The turtles grow quickly and have a life span of up to 40 years.) Animal rights groups such as PETA also rally against the sales and laud passersby for reporting shops that shill the creatures. Law enforcement agents seized 22 turtles from an NYC shop in 2013.

So far, James hasn’t gotten caught. Others have. In the summer of 2013, a vendor at the California Mid-State Fair faced criminal charges for distributing red-eared sliders as prizes when contestants successfully tossed ping-pong balls into rings. Officials from the California Department of Fish and Wildlife confiscated 65 turtles from the man’s stall—some as young as two weeks old and the size of a quarter, according to the Tribune, a newspaper in San Luis Obispo.

As for those that are recovered? Some are relocated to turtle rescue sites, but the FDA recommends humane disposal. Since turtles are cold-blooded, this generally involves freezing them into stupor. Any person hawking the small turtles or turtle eggs risks a $1,000 fine and up to a year in jail for each violation.

It’s surprisingly easy to get in on the turtle trafficking game. Shopkeepers brag that they can fulfill bulk orders overnight, offering a quick way to make a buck, or $7,000. With stalls overflowing with pashminas and $3 T-shirts, Chinatown lures tourists and locals willing to weather a crowd for a shoddy bargain. Sometimes they leave with faux-jade trinkets, and other times with a swimming souvenir.

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Jan. 28 2015 9:30 AM

Drones Help Rangers Fight Poachers

The Conversation

This article originally appeared in The Conversation.

In 2014, 1,215 rhinos were killed in South Africa for their horns, which end up in Asia as supposed cures for a variety of ailments. An estimated 30,000 African elephants were slaughtered last year for their tusks to be turned into trinkets. The world loses three rhinos a day and an elephant every 15 minutes. Simply stated, this is an unsustainable situation.


Our team at the University of Maryland’s Institute for Advanced Computer Studies has created a new multifaceted approach to combat poaching in Africa and Asia. We devise analytical models of how animals, poachers, and rangers simultaneously move through space and time by combining high resolution satellite imagery with loads of big data—everything from moon phases, to weather, to previous poaching locations, to info from rhinos’ satellite ankle trackers—and then applying our own algorithms. We can predict where the key players are likely to be, so we can get smart about where to deploy rangers to best protect animals and thwart poachers.

The real game changer is our use of unmanned aerial vehicles, or drones, which we have been flying in Africa since May 2013. We’ve found that drones, combined with other more established technology tools, can greatly reduce poaching in those areas where rangers on the ground are at the ready to use our data.

In the past 10 years, the poaching of elephants and rhinos has increased exponentially, primarily because it’s a very lucrative criminal business. Rhino horns can fetch more than $500,000 or more than $50,000 per kilogram—more than the cost of any illegal narcotic—and a pair of elephant tusks can reach $125,000. Most of these illegal activities are run by Asian criminal syndicates, and there are well-founded beliefs that some of these proceeds are being funneled to political extremists in Africa.

Technology is a marvelous tool, but it must be the right solution for a particular problem. Engineering solutions that might work with the U.S. military looking for people planting improvised explosive devices in Afghanistan will not necessarily work in the African bush, at night, searching for poachers. The most challenging question about how UAVs are used in Africa is when and where to fly them.

The drone is watching.

Courtesy of Thomas Snitch

Africa is too big to be simply launching small drones into the night sky with the hope of spotting rhinos or poachers by chance. This is where the analytical models come into play. Based on our models, we know, with near 90 percent certainty, where rhinos are likely to be on a particular night between 6:30 and 8:00, prime time for killings. At the same time, by mathematically recreating the environment when previous poachings have occurred, we have a very good idea of when and where poachers are likely to strike.

We don’t have to find poachers, we just need to know where the rhinos are likely to be.

For example, a large proportion of poachings occur on the days around a full moon; it makes sense since that’s when poachers can easily see their prey. In one area where we have months of experience, we discovered that nearly every poaching occurred within 160 meters of a road. It’s simple. The poachers are driving the perimeter of the park in the late afternoon, spotting animals near the park fence; they return just after sundown, kill the animal, and drive away. We pile on the data, and the algorithms do the rest.

The key is that the satellites, the analytics and math, and the UAVs are integrated into a solutions package. We crunch the data, and the model tells us precisely where we should deploy our rangers on any specific night so they will be in front of the rhinos and can intercept the poachers before they reach the target animal. After all, there’s no value in rangers patrolling parts of the park that these animals are unlikely to ever visit. Consider that South Africa’s Kruger National Park is the size of the state of New Jersey. Like a bank robber who robs banks because that’s where the money is, we want our rangers to be near the rhinos because that’s where the poaching is.

On our first UAV flight in South Africa, the UAV flew to our pre-determined spot and immediately found a female rhino and her calf; they were within 30 meters of a major road. We decided to circle the drone over the rhinos, and within minutes a vehicle stopped at the park’s fence. Three individuals exited the car and began to climb the fence to kill the rhinos. Our rangers had been pre-deployed to the area; they arrested the three poachers in less than three minutes. This episode has been repeated dozens of times over the past 20 months.

The most critical issue is not how far or how long a UAV can fly but how fast a ranger can be moved, in the bush at night, to successfully intercept poachers. The UAVs are simply our eyes in the night sky. Watching their live infrared video streams, we move our rangers as if they were chess pieces. Even with great math, we have some variance, and that means we might be 200 meters off a perfect positioning. The UAVs can see poachers at least 2 kilometers from the rhinos. So we have 45 minutes to move our people into the most optimal position, based on our real-world trials of how quickly they can move through the bush at night.

We’ve had hundreds of night flights with more than 3,000 flight hours in the past 20 months, and here is what we’ve learned. First, on the first few days after we begin operating in a new area, we arrest a number of poachers, and they’re being prosecuted to the fullest extent of local laws.

Second, our models are heuristic in that they are constantly learning and self-correcting, on the lookout for changes in the patterns they’ve identified. This is critical since poachers will try to change their behavior once they learn that they are at an extremely high risk of apprehension. The sheer number of animals being killed shows us that, up until the UAVs take to the air, most poachers have been able to operate with impunity.

The most important finding is that in every area where we have put our solutions package to work and the UAVs are flying, poaching stops with five to seven days. Period—it stops. Tonight we are flying in a very challenging area in southern Africa—we don’t identify our flight operations so as not to alert the poachers—and over the past 90 days, there has not been one single poaching incident. Four months ago, this region was losing several rhinos a week.

The good news is that we have proof of concept and proof on the ground that UAVs can make a tremendous difference. The bad news is that the poachers are moving to regions where we are not operating. To really address the challenges of poaching in the region, all the nations in southern Africa should be willing at least to test our system in their most critically endangered areas.

Our solution to the poaching problem lies in the combination of satellite monitoring, great math, properly positioned rangers, and UAVs flying precise flight paths. It works.

Jan. 27 2015 9:16 AM

A Perversion of Science

Two years ago, Western Australia announced a plan to indiscriminately kill large sharks in an attempt to make beaches safer. This shark cull was widely condemned by scientists and inspired Western Australia’s largest-ever public protest. Many species of large sharks are listed as threatened with extinction on the International Union for Conservation of Nature Red List. The best available scientific evidence suggests that culls like this do not significantly lessen the risk of sharks biting swimmers. And there are many less environmentally destructive ways to actually make the beach safer for swimmers, such as aerial patrols that alert people when a shark is nearby. The indiscriminate cull policy was abandoned last fall under pressure from the national government, but the Western Australian government reserved the right to kill specific sharks believed to pose an “imminent threat.”

A few weeks ago, one of the first sharks was targeted under this imminent-threat policy. It was identified based on data from a scientific telemetry tag that revealed that the shark was near a popular tourist spot called Warnbro Sound. Although a shark whose exact location is known poses no risk whatsoever to beachgoers—because you can simply not go into the water near where the shark is—the government decided to try and kill the shark.


These telemetry tags are a critical tool of scientific research. They help protect both people and threatened species of sharks by revealing how sharks use the available habitat. The tags are also used to study other important aspects of shark biology, including digestive physiology, three-dimensional habitat use, and the sounds found in their environment.

These tags are not designed to help fishermen or anyone else track and kill sharks (despite conspiracy theories from some fringe environmental activists). In fact, the data they collect is invaluable for conservation efforts. Using a tool designed for scientific understanding of a threatened species to track and kill that species is a perversion that infuriated scientists and conservationists. Researcher Andrew Fox of the Fox Shark Research Foundation told the Guardian that this “goes against everything we stand for,” and is a “complete waste of money, resources and time.” Fox is considering keeping the data from his tags secret if the government continues to abuse scientific tools in this manner.

Perhaps worst of all, the Western Australian government blatantly lied to concerned scientists about how these telemetry tags would be used. “There was concern amongst scientists from the first announcement of the imminent-threat policy that scientific tags would be used to help track and kill sharks,” Christopher Neff of Sydney University told me. He was explicitly told by a government official that telemetry tags would not be used in this manner, a lie that officials have continued to tell even after they were observed using tags to track and attempt to kill a shark. “It is clear that this is a system where scientific tags are being used destructively—to specifically track and kill great white sharks,” Neff said. “These actions take a step backwards in beach safety by killing sharks who are part of an early warning system and they take a step backwards in shark conservation by suggesting that we cannot share the ocean with sharks.”

After days of trying and failing to kill it, Western Australia Fisheries officers abandoned the search for this tagged shark in Warnbro Sound. The imminent-threat policy, however, remains in effect.

Jan. 14 2015 7:00 AM

Saving Mountain Gorillas, One Surgery at a Time

Jan Ramer is not your typical veterinarian. For one thing, she makes house calls, which might involve exhausting six-hour hikes through sloping, high-altitude rainforests just to reach her patients: critically endangered mountain gorillas. Then, to have a chance at successful treatment, Ramer’s team of vets, rangers, trackers, and assistants must tranquilize the sick animal without raising the ire of the silverback—the group’s dominant male, who can weigh in at 400 pounds or more.

On one ill-fated outing, a leery silverback didn’t appreciate the intrusion on his family, so he sunk his canines into a guard’s shoulder before running off into the forest, leaving the man in shock and the team with an aborted mission. (The guard survived and still works with gorillas.) Oftentimes though, the team is successful. They treat ailments such as respiratory infections and remove hunters’ snares.

Gorilla Doctors anesthetize and collect samples from silverback Inshuti during an intervention to free juvenile Ngwino from a snare in Volcanoes National Park, Rwanda.

Courtesy of Gorilla Doctors, © Gorilla Doctors,


Ramer is the regional manager of a nonprofit called Gorilla Doctors, based in the town of Musanze, about 90 kilometers from Kigali, Rwanda’s capital. Musanze serves as a jumping-off point for gorilla trekking in the Virunga Mountains, and it’s brimful with gorilla-themed tourist hotels and conservation organizations.

In the mid 1980s, the first “Gorilla Doctor,” James Foster, answered a call from Dian Fossey to bring veterinary care to the few hundred remaining mountain gorillas in Rwanda at the time. The vets now treat wild gorillas in the eastern Democratic Republic of Congo and in Uganda as well.

While ordinary conservation methods aim to minimize human contact with wildlife, the “extreme conservation” that Ramer and her colleagues practice turns that model on its head, seeking instead to make contact with the animals in order to save them.

As if the tough conditions and ornery patients weren’t enough, mountain gorilla territory in Congo’s North Kivu Province has a long history of violence and political instability. Recently the conflict has become a siege between the Congolese army supported by U.N. forces and around a dozen armed groups. Success on the battlefield against one enemy, such as the M23 rebels vanquished in late 2013, only seems to open the rugged North Kivu to a suite of other foes: relatively well-organized militias, including the Democratic Forces for the Liberation of Rwanda and Allied Democratic Forces of Congo; more amorphous and loosely allied Mai Mai groups; and outright bandits capitalizing on the chaos in the region. In April, Emmanuel de Merode, the director of Virunga National Park, survived gunshot wounds to the chest and legs from roving thugs who attacked him as he drove from Goma to park headquarters. More than 140 of the park’s rangers have been killed in the past 10 years.

The swirling mix of combatants pursue a variety of military, economic, and political aims, and many have rumored—or in some cases documented—links to other countries in the region, including next-door neighbors Uganda and Rwanda. But the one commonality tying them together is violence. It keeps alive thriving wildlife trade and bush meat markets for poachers; brings rape, torture, and other horrors of war to people’s doorsteps; and ensures that the region’s mainly subsistence farmers struggle to feed their families, even on Kivu’s fertile volcanic soils, as harvest after harvest is disrupted by war.

The vets’ work is extreme in almost every way imaginable. It’s expensive and dangerous, invasive and sometimes experimental, and it can change gorillas’ natural behavior. But for the fewer than 900 mountain gorillas in the wild, it’s also been an essential lifeline that’s working.

“Mountain gorillas are the only great ape population that’s growing,” says Ramer. “The only one.” There’s a hint of pride in her voice. Gorilla Doctors has something to do with that, and the group has the data to back it up.

In 2011, biologist Martha Robbins and her colleagues searched for trends in Virunga mountain gorilla populations using more than 40 years of data. They looked at growth rates for unhabituated gorillas, which had never been studied or administered veterinary care. And they looked the numbers of habituated gorillas—the groups that tourists and scientists visit and that thus can also receive medical attention.

While unhabituated gorilla numbers were declining slightly, Robbins found that the habituated group numbers were on the rise at around 4 percent a year. That’s an extraordinary clip for such a slow-reproducing species, one in which a typical gorilla mother has a single baby only every four to five years.

But why such a big difference between habituated and unhabituated gorillas? It certainly helps that guards protect habituated gorillas from poaching from sunup to sundown, seven days a week. But when Robbins looked at the Gorilla Doctors’ treatment records and estimated population changes that would have occurred if, for example, they hadn’t treated an infected snare wound and the animal had died, Robbins and her team figured that almost half of the habituated gorilla population’s growth could be due to the veterinary care.

Gorilla Doctors remove a poacher's snare from a mountain gorilla's wrist in Volcanoes National Park, Rwanda.

Courtesy of Gorilla Doctors, © Gorilla Doctors,

That then raises the question—if habituating gorillas helps so much, then why not habituate all of them? Limited resources, for one, says Robbins.

To achieve this “remarkable” growth rate, “It has taken a massive amount of effort,” she adds. The habituation process alone takes two years of daily visits before a gorilla family is ready to host photo-snapping tourists, inquisitive field researchers, or tranquilizer-toting veterinarians.*

And then there’s the possibility of disease transmission. Because we share 98 to 99 percent of our DNA with gorillas, depending on how you slice the double helix, we’re susceptible to a lot of the same diseases. Even simple human chest colds could lay waste to naïve ape immune systems, and increasing the number of gorillas in contact with people increases the chances that they’ll get sick, which could devastate their already-fragile numbers.

These complications point to the need to complement the Gorilla Doctors’ work with conventional, less intensive conservation tactics—cracking down on poaching, for example. “If there were no snares set in the Virungas, we would not need snare removals,” she says. And more robust traditional strategies could help both unhabituated and habituated gorilla numbers grow, not to mention being more cost effective.

Still, Robbins points out that “efforts of last resort,” such as near-constant guarding and vet care, have been, and remain, essential to mountain gorilla survival. “We have a conservation success story,” she adds. But with only around 880 animals left, that story is far from over. For the story to stay on the same trajectory, few conservation measures can be considered too extreme.


Courtesy of Gorilla Doctors, © Gorilla Doctors,

*Correction, Jan. 14, 2015, 4:30 p.m.: This article originally misstated how many years it takes for a gorilla family to be habituated to humans. It takes about two years, not five. (Return.)

Jan. 13 2015 8:30 AM

Monkeys Notice Themselves in Mirror, Immediately Examine Their Genitals

The ongoing saga of whether animals can recognize themselves in mirrors now has an important new data point. Clever research on the topic has found good subjects in primates, which tend to show an uptick in social behavior around mirrors and, in some cases, have the capacity to realize they’re looking at their own reflections. Since the first “mark tests” in the 1970s demonstrated this ability in some species, the existential primate staring into its own eyes has become an iconic image in animal-cognition research. (And superb fodder for YouTube videos.)

A new study on rhesus monkeys in Current Biology offers a spin on this question: Once animals do recognize themselves, what will they do with that knowledge? I will let this instant-classic video from the study take it from here:


Quizzically throwing their little legs in the air, the study’s monkeys did the natural thing in front of a mirror: They checked out their genitals.

The rhesus monkeys featured in the research don’t seem to recognize themselves in mirrors on their own. They haven’t passed the mark test, which would require them to show signs they recognize themselves when they look in the mirror after spots of dye have been placed on their faces. But it appears they can be taught this ability. Using a progression of colorful lasers and treats as rewards, researchers trained the monkeys to recognize foreign dots on their faces. Eventually, the enlightened primates seemed to notice themselves in mirrors.

Some scientists not involved in the study (including the developer of the original “mark test”) dispute the new results, reasoning that the monkeys merely behaved as they were trained—that they didn’t truly know what they were seeing. Regardless, the monkeys did seem curious about what lies beyond their faces, as Discover pointed out:

Without any prompting, researchers caught the little narcissists contorting and spreading their legs in front of the mirror to get a better look at previously unseen corners of their bodies. But who are we to judge?

Who indeed? Savor the knowledge that humans aren’t the only primates who contort in front of mirrors, and read more about the neural mechanism behind our self-recognition here.

Jan. 6 2015 10:36 AM

The Shocking Story of Electric Fish

Zeb Hogan had always kind of wanted to get shocked by an electric eel.

“Not in the daredevil kind of way,” he clarified, but as a matter of curiosity. Hogan is an aquatic biologist and host of a show on Nat Geo Wild called Monster Fish. He’s had his hands around myriad creatures most of us only know from legend, lore, and YouTube.


In a recent episode, Hogan and his team went to Brazil to look for electric eels in tributaries of the Amazon River. Traditional fishing methods failed to yield any of the creatures, so they turned to another approach, a fish trap constructed of fencing, nets, and a funnel. After a day of waiting, even that wasn’t working, so the whole crew hopped into the thigh-high water to pack up the trap.

“All of a sudden, we heard one of the cameramen yelling,” said Hogan.

The man was shaking, screaming, and clearly in pain. Everyone rushed over to check on him. There was no blood, no sign of attack by piranha or stingray or catfish, and yet even minutes later he was disoriented and confused about what had happened.

And then they realized: There were eels in the water after all.  

Sharks can be dangerous creatures, but only if you get near their mouths. Same with snapping turtles and Nile crocodiles. Tigers have claws, scorpions their stingers, and snakes their fangs, but in every instance, these animals can only harm you if they can touch you.

Not so with the electric eel (Electrophorus electricus), which is actually not an eel at all but a knifefish.

From the time it’s a tiny larva, the electric eel can generate a few dozen millivolts. As the animal grows, so does its zing. Full-grown adults can reach more than 8 feet in length and are capable of discharging around 600 volts into the water around them. Human deaths by electric eel are extremely rare, but that kind of power does have the potential to arrest the heart or cause respiratory failure. To fully understand this animal’s mayhem potential, just watch this amazing video of a caiman getting cranked by an eel.

Of course, it’s not as if electric animals are playground bullies, discharging their wrath indiscriminately. Their powers are used instead to sense the environment around them, communicate with their own kind, stun prey, and dissuade predators. A recent study even revealed that some eels can use their electricity to Jedi–mind-trick their prey out of hiding.

Now, imagine what it must have been like for an early human to encounter one of these fish or any of the numerous species of rays and catfish with similar powers: There’s no flash of light. The creature makes no sound. And yet the animals are clearly capable of walloping anything that wanders too close. This is a powerful and ancient magic.

“Three or four hundred years ago, electricity was literally considered to be an occult force,” said William Turkel, associate professor of history at Western University.

And though they did not understand how electric fish produced this energy, people were quick to try to harness it.

In his book Spark from the Deep, Turkel explains how the Romans applied live electric rays (also called torpedoes) to patients as a remedy for gout and headache. Nigerians reportedly dropped colickey babies into tubs containing several live electric catfish. And up until at least 1661, the repeated shock of a torpedo was said to cure even the most stubborn case of prolapsed rectum or uterus.

“Like many past medicinal treatments, you have to wonder if the cure was preferable to the ailment,” said Turkel. (No, Bill, I don’t think I do.)

But oh, it gets worse. As is often the case with early medicine, some of the participants in the studies of electric fish were not what you would call willing.

You’ve no doubt seen the videos of policemen standing arm-in-arm and then collapsing in unison to demonstrate the power of a Taser. Well, they used to do the same thing in colonial times, only the policemen were slaves, and the Taser was an electric eel, and the whole thing was a lark for the audience.

In another of Turkel’s examples, a young slave boy with crooked arms and legs was tossed daily into a tub with a large electric eel. Sometimes, he was able to crawl out of his own volition, though often someone else would have to haul the boy out of the water (and get shocked in the process). The treatment failed to straighten his shinbones.

Remember how ol’ Zeb Hogan sorta-kinda-maybe wanted to feel what it was like to get shocked by an eel?

“As the trip went on, I stopped feeling that way,” he said.

At one point during the show, Hogan and company visited a nature reserve so that they could catch an eel and measure its voltage. They had the animal corralled on a tarp and were handling it while wearing thick rubber gloves, but the eel was so powerful Hogan said he could feel a pervasive tingling sensation coming through.

“That was enough to set off alarm bells in my subconscious,” said Hogan. “It made me think, ‘This is something that I shouldn’t be doing.’ ”

Unfortunately for the electric fishes, the power they evolved to keep us away only drew us closer. In the 1700s and 1800s, humans became entranced by experiments with eels, rays, and catfish. The only problem was the animals were, literally, difficult to get ahold of.

One exhaustively named Prussian naturalist, Friedrich Wilhelm Heinrich Alexander von Humboldt, came by his test subjects by way of indigenous peoples in the Caribbean, but at great cost. To catch the eels, the Guayqueria Indians would drive 30 or so mules and horses into a pool at the river’s edge. All those thrashing hooves drove the eels out of the mud and up to the surface, whereupon they set to shocking the ever-loving hell out of the horses and mules.

It’s difficult to say which animals got the worst end of the deal here. After a time, the eels wore themselves out and were able to be drawn out of the water with small harpoons. However, by then many of the horses and mules had been zapped so thoroughly that they disappeared beneath the water’s surface and drowned.

Things didn’t get much better for the electric animals back at the lab. Dissections of every sort were carried out in order to understand where the electricity was coming from.

In the electric catfish of the Nile, the charge was traced to a pair of nerves that could be exposed with a single incision. This made the fish particularly useful in experiments, as opposed to the electric eel, which needed hundreds of such nerves across the length of its body to discharge its payload.

And this is where things get really weird.

In 1780, Luigi Galvani discovered that if you expose the sciatic nerves of a frog leg to static electricity, the leg would kick. (It had to be a frog, by the way. Toad legs twitched too much on their own and made for unreliable measurements.) For many decades after his discovery, a frog leg in a glass tube would remain the most sensitive electricity sensor in science. Fun fact: If you touch one of these sensors against the heart of a living animal, the frog leg will kick in rhythm with the heart’s beat.

For all of these reasons, frog legs were crucial tools in teasing out the secrets of electric animals. Turkel catalogs pages and pages of these bizarre stops and starts—electric rays connected to dozens of stacks of frog legs, the electric organ of a catfish wired to a phone receiver—but my favorite is called the “frog-alarum” or “frog-interrupter.”

First, you take an electric catfish and pin it to the bottom of its tank with a fish-shaped saddle. The saddle both keeps the animal in place and collects its electricity using tin foil at both ends. A pair of wires runs from the catfish to a galvanometer to measure the fish’s charge, then on to a freshly amputated frog leg attached to tiny hammer next to a bell. Then you put a loach in the tank, and wait for the electric catfish to strike.  

Before the frog-alarum, a scientist would have to sit beside the tank for hours on end so as not to miss any action. But now, thanks to this ghastly precursor to Mouse Trap, every time the catfish let out a shock, the bell would ring.

And ring and ring and ring. Poor loach.

Eventually, an invention called the Leyden jar would replace electric animal lab instruments. The new technology was a whole lot easier to care for and transport than a 9-foot fish that coughs up lightning bolts when it’s cranky.

“Of the fish I’ve dealt with, the electric eel is the most obviously capable of inflicting harm,” said Hogan. And that means a lot coming from a guy who routinely goes looking for giant stingrays, alligator gar, and Mongolian terror trout.

The good news, Hogan said, is that most electric animals want nothing to do with humans. Even the fishermen Hogan talked with, guys who have spent their whole lives on the Amazon River, had only a handful of electric eel encounters between them.

So as long as you aren’t a documentary filmmaker or a 19th-century electrophysiologist, you should be just fine.

Dec. 31 2014 4:19 PM

Drunk Finches Slur Their Songs

As midnight nears on New Year’s Eve, and you accept your third glass of prosecco, think of the zebra finch. The prolific creatures, common as pet songbirds around the world, are also popular among researchers because they are highly adaptable and very easy to breed. And as with most favored lab animals—think fruit flies, monkeys, and mice—scientists finally resolved this year to get them drunk.

In this case, scientists at Oregon Health & Science University decided to booze the birds to learn more about alcohol’s effects on speech. Zebra finches are very social and learn complex songs, and they have been studied as a model for how humans develop language. Past studies have found that finches glean song information from their relations much in the same way people do.


For the experiment, researchers offered zebra finches white grape juice with about 6 percent alcohol concentration, similar to many commercial beers. The birds “readily” accepted the liquid, according to the study in PLOS ONE. Once they reached a certain level of inebriation—about .05 to .08 percent blood-alcohol concentration—there were noticeable changes to their normal singing pattern. The birds' croons became lower and messier. The slurred songs can be heard in the slightly stilted video below; the recordings begin around 1:07:

Researchers wrote that although the birds seemed to avoid some of the more conspicuous signs of human drunkenness, like unsteadiness and general lack of composure, their off-kilter songs offered some clues about how we react to alcohol. As in any group of humans, the finches didn’t all have the same buzz—their acoustic structures vary naturally, and so did their boozy songs.

On New Year's Eve, let’s toast to the zebra finch, and allow the tiny birds to remind us that no one can endure too much of their white grape juice of choice without audible repercussions.

Dec. 30 2014 3:35 PM

What I Learned About Dogs and Love While Crossing the Country With My Lab

Excerpted from Travels With Casey: My Journey Through Our Dog-Crazy Country by Benoit Denizet-Lewis. Out now from Simon & Schuster.

Casey and I stopped in Sarasota, Florida, to meet Cary, a woman who’d read about my journey and suggested that I come meet her black Lab, Pepe. I told her and her husband, Mike, about Piper, a dog I was going to meet that afternoon in Tampa. Piper had bitten a home intruder two years prior, only to have the robber stab her with a crowbar.


“Poor dog,” Cary said. “If someone stabbed my dog, that would be like someone stabbing my child. To me, my pets are like my children. I love them the same.”

Although I adore dogs, I’m surprised when I hear people equate their love for their pets with their love for their kids. Did Cary actu­ally mean to say there’s no difference between the depth of love she feels for her daughters and the affection she has for her dog? If so, was that a sign of some advanced and egalitarian perspective on the value of dif­ferent species? Or was it a sign of insanity? Whatever the case, did Cary really want her daughters to see that in print?

“I don’t have kids,” I told her, “but I imagine that I would love them in a different way than the dogs I’ve loved in my life.”

Though Cary couldn’t tease apart her love for her dogs and her children, she was quick to differentiate between how kids and dogs love their human caretakers. “Dogs never become teenagers,” she told me. “It’s a consistent relationship; the quality of their love for you doesn’t change. They don’t grow up and tell you that you’re the worst. They don’t move out. Even if you screw up, they don’t hold it against you.”

Mike chimed in, “Dogs are like kids, but without the drama or the attitude.”

Cary went on, “A dog’s love is different from human love, because it’s truly unconditional.”

Is it, though? Patricia McConnell writes that “it’s become a cliché that we love dogs because they give us unconditional positive regard.” McConnell calls this belief “naive” and suggests we’ve “convinced ourselves that our dogs love us constantly and relentlessly, simply be­cause we’re not very good at reading their nonverbal communications to us.”

Anthony Podberscek, who studies the human-animal bond, told writer Hal Herzog that the unconditional love theory of pet owner­ship is “rubbish,” a peculiarly American phenomenon that’s dismissive of the intelligence and emotional complexity of pet animals. Podber­scek argues that if we truly believe “that our pets are programmed to mindlessly love us no matter what we do to them,” Herzog reports in his book Some We Love, Some We Hate, Some We Eat, “they are essentially Cartesian robots that take whatever we dish out for them and then come back for more.”

Still, I could understand where Cary was coming from. Adolescent dogs are less likely to “hate you” than adolescent humans. As psychiatrist and educator Aaron Katcher once wrote, “a dog is like an eternal Peter Pan, a child who never grows old and who therefore is always available to love and be loved.” Andy Rooney may have pinpointed another ad­vantage that dogs have over kids: We don’t have to listen to dogs com­plain.

“If dogs could talk,” Rooney once said, “it would take a lot of the fun out of owning one.”

* * *

Earlier that week, I’d attended the 19th Annual International Confer­ence on Comparative Cognition at the Radisson Hotel in Melbourne Beach, Florida. (Casey had to stay in the RV because he wasn’t allowed in the hotel.) The most pressing concern for canine cognition researchers was the motivation of the American dog. Can dogs be said to love us? Researchers across the world are struggling with variations of that question. Some, like neuroscientist Gregory Berns, flat out equate dogs to people in this regard and insist that canines very much love us. Others don’t go nearly that far.


“Do dogs hang out with us mostly because we’re treat-dispensers, or can they be said to have a real and genuine affection for us?” won­dered Erica Feuerbacher, a conference attendee who was a Ph.D. candi­date at the University of Florida at the time. We spoke on the hotel patio, only feet from the beach. “Has something changed along domestication from wolves where our interaction or our presence is rewarding to them in itself?” she said. “We have these sayings in everyday life about dogs and uncondi­tional love, and dogs being ‘man’s best friend,’ but what produces and maintains that relationship? We don’t really know.”

To begin to explore that question, Feuerbacher devised an experiment to test whether dogs would work harder for a reward that consisted of food or human petting. The results were predictable—and depressing. Dogs want our treats more than they want our love.

The University of Florida’s Canine Cognition and Behavior Lab was led at the time of my visit by psychologist Clive Wynne, a former pigeon researcher considered by some to be the Debbie Downer of the canine cognition field. (He has since moved to Arizona State University.) Among those who study the intelligence and emotions of dogs, Wynne has perhaps been the most adamant about not looking through the lens of anthropomorphism.

“People may behave like animals,” he once said, “but dogs are just good at being dogs.”

“Our love for dogs can sometimes lead us—even those of us who are supposed to be guided by the science—to exaggerate just how much they truly grasp,” Wynne told me during a break at the confer­ence. Though dogs’ behavior can seem uncannily human, Wynne stresses that dogs have vastly different cognitive and perceptive abilities. “I un­derstand why people sometimes think their dogs are incredibly intel­ligent, to the point of being able to sometimes read our minds,” he said. “When you get up from your chair at home, sometimes you’re headed to the bathroom, sometimes you’re headed to the kitchen to make coffee, and sometimes you’re headed to take the dog for a walk. Why does the dog so often stay lying down when you do the first two, but not the third? Is the dog a mind-reader? No. But your dog is a master at observing you and looking for any correlations between your move­ments and the crucial outcomes for the dog—being fed, going to the bathroom, that kind of thing.”

Wynne believes that dogs learn by socialization and observation, and that there’s not all that much difference between the brain of a dog and a wolf. Others, including Brian Hare, who runs the Duke Canine Cognition Center, fundamentally disagree, arguing that domestication has rewired the dogs’ brains and given them a remarkable ability to understand human gestures and cues.

“Brian and I have a massive disagreement,” Wynne said, “and we could probably make some money by going on the road and debating this.”

Wynne and Hare do agree on one thing, though: They’re not all that interested in figuring out whether dogs are as smart as 2-year-olds. When I visited Hare earlier in my journey at his Duke University lab, he told me that dog lovers often want answers to questions that can’t really be measured.

“At my lab, we’re not trying to understand if dogs are little people,” Hare said. “I understand why people want to know if their dog is as smart as a 2-year-old—the dog lover in me kind of wants to know that, too. But from an evolutionary perspective, that question doesn’t make a lot of sense. If I had some magic way to transplant a chim­panzee brain into a dolphin and a dolphin brain into a chimpanzee, that wouldn’t tell us much, because each brain has evolved to solve really different problems.”

After visiting Cary and Mike, I stayed on the topic of kids and dogs later that afternoon in Tampa, when I visited a stay-at-home mom named Kim and her dogs, Piper (the mutt who’d been stabbed by the intruder) and Hunter (a Brittany). We sat with Kim’s mother and daughter on the back patio overlooking their pool and the ballfields of an adjacent middle school. As we spoke, two squirrels tortured Piper, Hunter, and Casey by racing back and forth on top of a wooden fence.

After I told them about my conversation earlier that day in Sara­sota, Kim’s mom, Carol—a youthful and funny psychotherapist in her 60s—recalled the pain of losing her favor­ite dog, Shoshanna. “She died a few years after my husband passed,” Carol said, “and what made it especially painful was that she was my connection to my husband. It was his dog, his love. I mean, he let that dog sit on the table at dinner! When Shoshanna died, it brought up all the feelings of losing my husband again.”

At that moment, Casey, who had been wandering through the yard, spotted an armadillo on the other side of the chain-link fence that sepa­rated Kim’s property from the school’s fields. He let out two barks in quick succession and rushed toward the fence, but he could only watch as the armadillo—moving with surprising deftness for an animal carry­ing an armored shell—scurried away.

“It’s certainly the natural cycle for dogs to die before us,” Carol continued, “and in many ways they teach us how to deal with loss.”

I looked at Casey, who had forgotten about the armadillo and was now busy sniffing a bush. It occurred to me—I mean, really occurred to me—that he wouldn’t live forever. I felt a tightness in my chest, a kind of panic.

“I don’t want Casey to die,” I heard myself saying out loud, though I’d only intended the words for myself.

Then I thought about what might happen if I died before Casey. Who would look after him? I hadn’t prepared a will, hadn’t made any arrangements. But those were mere practicalities. Where my mind went, I’m ashamed to admit, is toward more ego-based questions: Would Casey even notice that I was gone? Would he be sad? Would he mourn me? The answers seemed painfully clear to me that afternoon in Florida: maybe, probably not, and no.

From Travels With Casey: My Journey Through Our Dog-Crazy Country by Benoit Denizet-Lewis. Copyright © 2014 by Benoit Denizet-Lewis. Printed by permission of Simon & Schuster Inc.

Dec. 8 2014 3:02 PM

Discovery Channel Is Getting Eaten Alive for Eaten Alive

A month ago, the Discovery Channel promised a new journey into the world of the gratuitously grotesque: A man was going to wade into the Amazon, douse himself in pig’s blood, and get eaten alive by a giant anaconda. Several media outlets, Slate included, were more horrified than impressed. When the episode aired Sunday night, those who eagerly tuned in were treated to their own dose of outrage when they found out they’d been duped. Nobody got eaten alive on Eaten Alive. (Sorry if that was a spoiler.)

The reaction on social media, as noted by Business Insider, was snarky and swift. People felt misled—and rightfully so. As it turned out, stuntman Paul Rosolie had to stop the encounter with the snake due to the crushing pain he felt as the anaconda ingested his arm—he feared it might break. Rosolie, a naturalist, told AFP the stunt was meant to harness shock value to raise people’s concern about the rainforests. And to its credit, Discovery did link to a fund for protection and research of the Amazon rainforest. But people tuning in hadn’t seen a word about conservation in the ads promoting the show, or even seen video clips of creatures losing their habitat. They were promised one thing: A guy getting swallowed by a giant snake. And their disappointment definitely doesn’t help the rainforest.


This stunt and the deceptive campaign were no accident: Eaten Alive is one more entry into a collection of disappointing Discovery programming that capitalizes on sensationalism and misinformation. There are obvious dangers to misleading the public on science, and Discovery has a disturbing history of, for instance, claiming that extinct giant sharks aren’t extinct. But however misleading those shows were, at least they misled in the way their titles promised. Now Discovery has made a step into another irritating territory—clickbait.

The essential ingredients for clickbait are all there: Misleading title? Check. Disappointing content? Check. Frustrated audience? Double check.

A lot of people were hate-watching Eaten Alive the way they might watch so-bad-it’s-bad Sharknado. But I have very little pity for people who wasted two hours staring at their televisions with bated breath, waiting for a perversely voyeuristic climax that never arrived. I actually think it’s pretty funny. But I worry what this says about supposed “documentary” television. The one thing Eaten Alive had going for it in the first place was that it was supposedly real. But since when does an incomplete stunt go anywhere but the cutting room floor? I am glad Rosolie was concerned enough about the danger to call it off. But this wasn’t filmed live—why did it air? Discovery could have cut its losses. But the company ran with it, and found a new low in shock value programming: A great teaser is enough, and quality content—or even complete content—is simply optional.

Hopefully the social media furor from those who endorsed the show with their viewership will at least dissuade Discovery and other channels like it from doing this kind of thing in the future. I’d hate to see March of the Penguins: The Sequel 30 years from now, only to sit through two hours worth of searching the Antarctic for some penguins.

Nov. 28 2014 12:36 PM

Why Female Jacanas Do All the Fighting

Excerpted from Animal Weapons: The Evolution of Battle by Douglas J. Emlen. Out now from Henry Holt and Company LLC.

Jacanas are bizarre birds, especially when it comes to their weapons. The female I’m watching has especially big spurs, one on each elbow, and she creeps about with delicate steps on very long legs. Her slender toes splay to a span of more than 5 inches per foot, and her gait brings to mind a carnival stilt walker. This female, “red-over-blue-and-white right” (named for the colored ring bands on her right leg), is making the rounds of her territory, checking the nests of each of her four mates. Her territory is difficult to get to, and we have to watch at a distance from a canoe. Jacanas defend areas of floating vegetation on wide tropical rivers. Panamanians call them “Jesus” birds because they look like they walk on the water and, in a sense, they do. They tiptoe across their floating mats, dispersing weight with each step over delicate toes, balancing atop the bobbing rosettes of water lettuce and hyacinth.


This morning, red-over-blue-and-white right is fighting again, as she so often does. An unmarked female had darted in from the adjacent shoreline, hiding in the hyacinth leaves behind one of the males, but our territorial female spots her immediately and closes in. Now, face to face, the two birds size each other up. Crouching low, elbow spurs flared out to the sides, each sidesteps the other in a slow circle. Then red-over-blue-and-white right pounces, leaping into the air and striking the intruder feet first on her way down, slashing out with her spurs. Everything whirls into a blur as both birds leap at each other over and over, crashing together and jabbing as they flail onto the mat of floating lettuce, pop to their feet, and leap once more. And then suddenly the fight is over; the intruder flies away, and the thick air rings with raucous ka-ka-ka-kas as our focal female proclaims victory to birds nearby.

Hundreds of vagrant females forage along the nearby shores of the river. These individuals have failed to secure an island territory of their own, and they challenge the resident females incessantly, pressing and probing, searching for weakness. For vagrants these battles are “do or die,” since failure to secure a territory is an evolutionary full stop, a dead end. Unless they can find a way to displace one of the owners, their chances of breeding are nil.

Female jacanas are fighters, towering over the males. They are stronger than males, vastly more aggressive, and they have the larger weapons. Sharp yellow spurs jut forward like daggers from each elbow. Bigger females fare better in fierce battles, and as a rule only dominant, top condition females manage to hold a territory for long enough to breed.

Males also fight for territories on the floating mats, though their battles are less vicious and are independent of the wars waged by the females. Males fight with rival males, and successful individuals defend patches of floating greenery sufficient to raise a clutch of chicks. These territories pack into the floating islands like tiles of a mosaic, with the female territories superimposed on top. Some females may be able to shove rivals away from only a single male territory, but the biggest and best females own enough island to house three or four males.

My female is engaged in yet another fight—her fourth of the morning. The male shepherds his brand-new chicks as they wobble from plant to plant, all feeding on little insects squirming at the water surface around the lettuce.

The next male over, his territory also nestled within the holdings of red-over-blue-and-white right, still has eggs, and he sits on his hidden nest sheltering his clutch. A third male has nearly grown chicks, and the last male is between broods, ready to begin the process again. Our female, when she’s not battling to hold her spot, moves freely among her males, mating with them from time to time. When one of her males is ready, she’ll lay a clutch of four eggs into his nest. But then she will abandon the eggs to the male and move on, placing her next clutch a few weeks later into the nest of a different male. Male jacanas spend several months tending to young each time they reproduce, preparing nests, incubating eggs, and shepherding the chicks as they grow to independence. Females show up to provide eggs when needed, but otherwise they leave the tending of young to the males.

Jacanas seem backward. Females are more aggressive than males, they are larger than males, they fight more viciously and frequently than males, and they have larger weapons. In the animal kingdom, usually it’s the other way around. In flies, beetles, mastodons, crabs, and elks, males are armed, not females. Jacanas excepted, in every species with weapons confined to a single sex, males have those weapons. Why should just one sex have weapons? And why is it (almost) always the males?

Females of all animal species produce larger reproductive cells (called “gametes”) than males. Eggs are bigger than sperm, and this difference in material investment is far more substantial than most of us appreciate. Humans are rather ordinary in this respect, but we’re a good place to start. The female egg is the largest cell in the human body. It measures almost a fifth of a millimeter across—about the size of a period (.) on this page—and it’s just visible to the naked eye. Sperm are the smallest cells in the body, and 100,000 could fit into the volume of a single egg.

In many animals differences in egg and sperm size are much more profound. A zebra finch mom fits nicely in the palm of your hand. She’s roughly 4 inches beak to tail, but she lays an egg that is more than a ½ inch across. By weight, a finch egg is 7.5 percent of the weight of her body. That’s equivalent to a human female producing an egg weighing 11 pounds. Kiwis have the most gargantuan of all gametes, relative to their body size: brown kiwi moms lay eggs that are a fifth of their body weight. Our human mom would need to produce a 30-pound egg to compare—the size of an 18-inch watermelon.

Asymmetry in gamete size has consequences that ripple through the biology of animal species. For one thing, females can’t produce as many gametes as males do. With the same amount of resources, males produce trillions of sperm. And these numbers stack up fast, since each male produces similarly copious quantities of sperm. A human female produces roughly 400 viable eggs over the course of her lifetime. A male, on the other hand, cranks out 100 million sperm every day, easily 4 trillion over his lifetime. Scale that up to a population of 1,000 people, and there are a quadrillion (that’s 15 zeros) more sperm than there are eggs. Scale it to the current human population and there are a septillion (24 zeros) more sperm than eggs. And humans aren’t even an extreme example. The simple fact is that in virtually every animal species there are nowhere near enough eggs to go around. The result is competition.


The size of female gametes is important for another reason. Large, nutrient-rich eggs are expensive, and they take time to produce. Depending on the species, females may take days or even weeks to recover from producing one batch of eggs before they are ready to lay another. Males, on the other hand, tend to need only a few minutes. Thanks to their gametes, females generally take longer to “turn around” between breeding events than do males.

Females also stand to lose more than males if a breeding attempt fails. Although each sex invests nutrients, energy, and time in producing gametes, the amounts they invest are different. Females spend more than males each time they reproduce and, because of this, the cost of abandoning a brood is much steeper for females than it is for males. As a result, whenever additional offspring care is required, it’s generally the females who provide it.

Females invest in offspring in all sorts of interesting ways beyond simply producing eggs. Cockroach moms hold fertilized eggs inside their bodies until they are ready to hatch, feeding and protecting them in an insect equivalent of a mammalian pregnancy. Scorpions wear bundles of babies on their backs for weeks after they hatch. Dung beetle moms excavate tunnels into the ground and provision their babies with balls of buried dung; a few species even lock themselves inside a crypt for a year so they can guard the young as they grow.

Preparing nests, pregnancy, guarding eggs, and feeding and protecting young all take time. These forms of maternal care can increase the latency between reproductive events still further, compounding the rift in relative investment between the sexes. Males can invest in offspring, too, as they clearly do in jacanas and humans, but it’s surprisingly rare in the animal world. In most animal species, males provide little more than sperm, and this means they recycle an awful lot faster than females.

Turnaround times are tremendously important for explaining animal weapons because whenever they differ between males and females the result is always competition. If you walk into a population of just about any animal species, and you count how many individuals of each sex are physiologically capable of breeding right now, you’ll find that all the males are able and willing, but many of the reproductive-age females are not. Some of the females are physiologically unavailable—out of commission, so to speak—in between broods. Female zebras in the midst of pregnancy cannot conceive new foals. Cow elks cannot start new pregnancies while they are nursing existing young. Females that are locked into a current breeding event are “out of the pool” since they are not available for conceiving new young. If all of the males are able to breed, but only a fraction of the females are, then there will not be enough females to go around.

Enter nature’s most pervasive and potent form of competition, what Charles Darwin called “sexual selection.” Individuals of one sex compete for access to the other. In principle, sexual selection can work both ways, with either males or females competing. In reality, except for rare cases such as the jacana, it almost always involves males competing for access to females. Female jacanas still produce the larger gametes (eggs are bigger than sperm), and it takes them a few weeks to recover between clutches. But this is where female investment stops. Male jacanas spend up to three months tending to eggs and chicks, and as a result their turnaround time is longer than the females’. Females recycle roughly three times faster than males (24 days compared with 78 days), translating into almost three times as many reproductively ready females as males on floating territories. At any point in time, roughly half of the males in a population are tied down with existing eggs or chicks, leaving just a few of them free to start new broods while most of the females are yolked up and ready to go. They could lay eggs immediately if only they had access to a territory-holding, reproductively ready male. In jacanas, there simply are not enough receptive males to go around, and females battle it out for the chance to breed. Sexual selection, rather than selection from predators or prey, drove the evolution of blazing yellow spurs in jacana females.

llustration by David J. Tuss. Excerpted from Animal Weapons: The Evolution of Battle by Douglas J. Emlen, published November 2014 by Henry Holt and Company LLC.  Copyright © 2014 by Douglas J. Emlen. All rights reserved.