The Riddle of the Ridley

Editor’s note: This is part of a series highlighting the seven species of sea turtles during #SeaTurtleWeek. A different species will be highlighted each day. For more information on other Sea Turtle Week activities offered by the Sea Turtle Preservation Society, please go to our website or visit us on Facebook and Instagram.

By Susan Skinner

The history of the Kemp’s ridley sea turtle reads like the pages of a mystery novel rather than a biology textbook, taking readers on a quest filled with folklore, surprising biological clues, an inspiring cast of characters, and a life-or-death crisis.

Renowned sea turtle conservationist Archie Carr spent decades researching what he called “the riddle of the ridley,” and his 1956 book, The Windward Road, recounts his travels through the Caribbean in search of answers.

The story of the Kemp’s ridley actually began some 80 years earlier when Key West businessman and avid naturalist Richard Kemp took notice of the sea turtle. Kemp became fascinated with these sea turtles that were unlike any other he had known growing up in The Bahamas. He sent descriptions and specimens to Harvard, and in 1880 the species was named in his honor.

Carr’s role in the story began when he traveled to the Florida Keys in 1938 and saw for the first time what a colleague had reported as an “evil-natured” sea turtle that locals called a ridley. He heard the local stories surrounding these turtles: no one knew where they nested, some believed the turtles to be hybrids of loggerheads and greens, and some called them the “heartbreak turtle” because they fought so aggressively when placed on their backs that they exploded their hearts and died.

Carr spent the next two decades searching unsuccessfully for the nesting grounds of the Kemp’s ridley throughout Florida, The Bahamas, the Caribbean and the northern Gulf of Mexico.

Before the riddle would be solved, two new characters would need to introduce additional clues to the story. In 1947, Andres Herrera filmed a large nesting event, or arribada, in progress near Rancho Nuevo, Mexico. This now famous footage is the earliest documentation of a nesting site for the Kemp’s ridley as well as mass nesting behavior in sea turtles.

However, it wasn’t until 1961 when biologist Henry Hildebrand came across the film while in Mexico and presented it to the scientific community (Carr included), that the pieces fell in place to solve the riddle of the ridley.

While the scientific community was just learning of the existence of the Kemp’s ridley and its nesting site, this species already was on the brink of extinction. Exploitation of eggs at Rancho Nuevo combined with an expanding shrimping industry in the Gulf threatened the very survival of the species.

The film of the arribadas led the Mexican government to protect the nesting beaches in the late 1960s, but nesting numbers continued to decline in the 1970s despite these protections and others by both the United States and Mexico. Realizing protecting the nesting beaches alone was not enough, NOAA Fisheries developed a turtle excluder device, or TED, to address the thousands of sea turtles being caught in shrimp trawler nets. With the implementation of this device, all sea turtle species benefited through reduced deaths, and Kemp’s ridley nesting numbers increased dramatically from 1985 to 2009.

In solving the original riddle of the ridley, scientists revealed the nesting site of the species as well as the arribada behavior. The Kemp’s ridley also has played a leading role in the development of the TED, a significant achievement in sea turtle conservation.

The latest chapter in the history of the Kemp’s ridley contains yet a new riddle, as scientists grapple to understand recent downturns in nesting for this critically endangered species.

To learn more about the Kemp’s ridley sea turtle, please try these resources:

State of the World’s Sea Turtles Report, Vol. 10: February 2015

State of the World’s Sea Turtles Report, Vol. 5: February 2010

Sea Turtle Week Kemp’s ridley page

The Windward Road: Adventures of a Naturalist on Remote Caribbean Shores, by Archie Carr. First published in 1956.