Hawksbill Sea Turtle, Eretmochelys imbricata

Hawksbill Sea Turtle, Eretmochelys imbricata. Underwater photographs taken in Zihuatanejo Bay, Guerrero, March, November and December 2018. Photographs courtesy of Ron Woheau, Zihuatanejo.

Hawksbill Sea Turtle, Eretmochelys imbricata. Underwater photographs taken in coastal waters off Puerto Vallarta, Jalisco, June and July 2023. Photographs courtesy of Kevin Erwin, Seattle, Washington.

Phylogeny:  The Hawksbill Sea Turtle, Eretmochelys imbricata (Linnaeus, 1766) is a member of the Cheloniidae Family of Sea Turtles. The genus Eretmochelys is one of seven genera in this family, and this is the only species in this genus. The are currently two accepted subspecies- The Pacific Hawksbill Sea Turtle, Eretmochelys imbricata brissa and the Atlantic Hawksbill Sea Turtle,  E. imbricata imbricata. This species is also called Carey- meaning horn-like, in reference to its “tortoise-shell” carapace. In some Spanish speaking regions it is called either tortuga marina de carey or carey de concha.

Morphology:  Hawksbill Sea Turtles have an oval shaped carapace (shell). The carapace shields overlap and the carapace margin is serrated. There are four pairs of costal shields and two pairs of prefrontal ( in front of eyes) shields. The head is narrow and tapering. The beak is sharp and overlapping, like a raptor’s beak. The carapace is mottled with colors including red, orange, yellow, green, brown, and black. The plastron (ventral shell) is yellowish with black spots. Each of the flippers have two claws. Hawksbill Sea Turtles reach 90 cm (3 feet 0 inches) in length and 136 kg (300 pounds) in weight, though most individuals are about half this size.

Habitat and Distribution:  Hawksbill Sea Turtles are usually found in shallow coastal areas and lagoons. They frequent coral reefs and rocky areas. While some sources claim that Hawksbill Sea Turtles can dive as deep as 200 m (656 feet) and stay submerged for up to 140 minutes, most sources are more conservative. Most of their time is spent at depths of 2-20 m (6-66 feet). Hawksbill Sea Turtles are the most tropical of all sea turtle species. They are found in tropical and subtropical regions of the Atlantic, Indian, and Pacific Oceans. In Mexican waters they are found in the Gulf of Mexico, Caribbean, Gulf of California, and the Pacific off of the Mexican mainland.

Diet:   Hawksbill Sea Turtles are carnivorous predators, feeding primarily on sponges. They also eat anemones, squid, and shrimp.

Predators:  Adult Hawksbill Sea Turtles are eaten by sharks, crocodiles, large fish, and octopuses. Hatchlings face additional threats from crabs and sea birds. Sea turtles eggs may be eaten by shore birds, dogs, crabs, raccoons, skunks, and other mammals.

Reproduction:  Hawksbill Sea Turtles are gonochoric (male or female for life). They reproduce sexually, with internal fertilization. Females lay their eggs in a hole in the sand on the same beach where she hatched. She digs the hole using her flippers. She will lay 70-200 eggs at a time.  The eggs hatch about 60 days later. Approximately 700 Hawksbill Sea Turtles nest every year in the Eastern Pacific, from Mexico to Peru.

Ecosystem Interactions:  Hawksbill Sea Turtles sometimes host the ectoparasitic Marine Turtle Leech, Ozobranchus margoi. This leech sucks blood from the turtle. Sea turtles also host a variety of commensal species of barnacles, crabs, shrimp, algae, bryozoans, oysters, bristle worms, polychaetes, brittle stars, and other organisms on their shells. Most of these organisms derive the benefit of transportation from the relationship. These organisms can slow the turtle’s movement through the water, but not usually to the detriment of a healthy turtle.

Human Interactions: Hawksbill Sea Turtles have been hunted for centuries as a food source and because of their beautiful shells. As a result, they have been overfished in many areas. They are also subject to entanglement of fishing gear, and boat strikes. Sea turtle eggs are harvested by humans and are eaten by introduced animal species. Loss of nesting habitat and marine pollution, including plastic pollution, also take a toll on turtle populations. From a conservation perspective the Hawksbill Sea Turtle are currently considered to be Critically Endangered. They are also listed as Endangered under the Endangered Species Act within the United States.

Synonyms:    Eretmochelys squamosa and Testudo imbricata.