Monkey Island, the Puerto Rican place where primates run amok
Tales of Monkey Island
Atlas Obscura
Your Guide to the World's Hidden Wonders
Jan. 3 2014 10:49 AM

Monkey Island, Where Playful Primates Run Amok

Atlas Obscura on Slate is a blog about the world's hidden wonders. Like us on Facebook, Tumblr, or follow us on Twitter @atlasobscura.

Monkey Island is real! Not the Guybrush Threepwood, Mighty Pirate version, but a research facility overrun with primates. Half a mile off the eastern coast of Puerto Rico is Cayo Santiago, an island teeming with free-ranging Rhesus monkeys. Researchers from Harvard, Yale, and the University of Puerto Rico's Caribbean Primate Research Center visit the island to study the monkeys' behavior, development, communication, and physiology.

The simian population numbers around 800. All monkeys on the island are descendants of the 409 monkeys imported from India in 1938 to establish the facility. Cayo Santiago has no human inhabitants — researchers commute to and from the Puerto Rican city of Humacao each day. Visitors are not permitted, and with good reason: Rhesus monkeys may carry Herpes B, a virus that can be fatal to humans.


Kayak trips to Monkey Island leave from Punta Santiago. You'll be required to stay 30 feet from the island, which is still close enough to spot some monkeys running wild.

The view from Cayo Santiago.

Photo: schizoform on Flickr

Other islands ruled by animals:

View Monkey Island in a larger map
  Slate Plus
Slate Archives
Nov. 26 2015 10:00 AM Slate Voice: “If It Happened There,” Thanksgiving Edition Josh Keating reads his piece on America’s annual festival pilgrimage.