Hawksbill Sea Turtle (Eretmochelys imbricata): Facts and Diet

What does a hawksbill sea turtle look like?

The hawksbill has a relatively narrow, pointed head that ends in a sharply hooked beak, giving it the look of a bird of prey. Its scientific name describes another key feature: imbricata means “overlapping,” for the thick shell plates, or scutes, that overlap like roof shingles. Toward the back of the shell, the scute edges form a serrated, saw-like margin, which becomes smoother in very old turtles.

The upper shell, or carapace, is usually amber with an irregular pattern of streaks and splashes in brown, black, orange, red and yellow. The lower shell is pale yellow. Other identification features include two pairs of scales between the eyes, four pairs of scutes along each side of the carapace, and two claws on each front flipper.

Males have longer claws, longer and thicker tails and a slightly concave lower shell, and they are often more brightly colored than females. Hatchlings are mostly dark brown, with a heart-shaped shell. In 2015, divers in the Solomon Islands filmed a hawksbill glowing red and green under blue light, the first reported case of biofluorescence in a reptile.

How to tell a hawksbill from a green turtle

Snorkelers and divers often confuse hawksbills with green sea turtles, which share many of the same reefs. The head is the best clue: a hawksbill’s head is narrow and ends in a pointed, overlapping beak, while a green turtle has a short, rounded snout. Hawksbills have two pairs of scales between the eyes, green turtles only one.

The shell helps too. Hawksbill scutes overlap and form a jagged rear edge, whereas a green turtle’s scutes sit edge to edge and the shell margin is smooth. Loggerheads, the third reef visitor, have a much larger head and five pairs of side scutes instead of four. On nesting beaches, hawksbills leave asymmetrical tracks because they move their flippers alternately, while green turtles leave symmetrical tracks.

How big do hawksbill turtles get?

The hawksbill is one of the smaller sea turtles. Adults usually have a shell 60–95 cm (2–3 ft) long and weigh about 45–70 kg (100–150 lb), and nesting females average about 87 cm (34 in) in curved shell length and 80 kg (176 lb). The largest recorded shells were about 1.1 m (3.7 ft) long, and the heaviest hawksbill on record weighed about 127 kg (280 lb).

For comparison, adult green sea turtles often weigh well over 100 kg (220 lb), while leatherbacks can exceed 500 kg (1,100 lb).

Where do hawksbill turtles live?

Hawksbills live in tropical and, less often, subtropical waters of the Atlantic, Indian and Pacific oceans. Of all sea turtles they are the most closely tied to warm, tropical seas. In the Atlantic they range from the Caribbean, the Gulf of Mexico and southern Florida to Brazil and West Africa. In the Indian Ocean they occur along East Africa, around Madagascar and the Seychelles, in the Red Sea and the Persian Gulf, and along southern Asia. In the Pacific they range from southern Japan through Southeast Asia to northern Australia, the Solomon Islands and Hawaii, and along the Americas from Mexico to Peru.

Adults spend most of their time on coral reefs and rocky reefs, resting in caves and under ledges. They also use lagoons, seagrass areas and shoals where sponges grow. In the eastern Pacific, where the species was once thought almost gone, hawksbills were found living and nesting mainly in mangrove estuaries, such as Bahía de Jiquilisco in El Salvador.

What do hawksbill turtles eat?

Sea sponges make up most of the hawksbill’s diet, often 70–95% of what it eats. It is the only reptile known to specialize in sponges, many of which are toxic or packed with sharp, glassy needles of silica. Hawksbills are choosy, feeding on a limited number of sponge species and ignoring many others.

They also eat soft corals, zoanthids, sea anemones, algae, jellyfish, sea squirts, mollusks, crustaceans and small fish. Their narrow beak lets them reach into small holes and crevices in the reef. Because they eat toxic sponges and stinging animals, hawksbill meat can itself be poisonous to people. Find out more in what do hawksbill turtles eat?

Why hawksbills matter to coral reefs

Sponges compete with reef-building corals for space on the reef. By cropping large amounts of sponge, hawksbills are thought to help keep that competition in balance, giving slow-growing corals more room to settle and grow. Healthy reefs in turn provide hawksbills with food and with the caves and ledges where they rest.

The hawksbill is also unusual in evolutionary terms: it is the only living species in its genus, Eretmochelys. The Zoological Society of London includes it among its EDGE species, animals that are both globally endangered and evolutionarily distinct.

Behavior and migration

Hawksbills are solitary for most of their lives and meet mainly to mate. Young hatchlings head out to sea and drift for roughly 1–5 years, sheltering in floating mats of seaweed and debris. Once they reach about 20–30 cm (8–12 in), they settle on shallow reefs, where many stay in a fairly small home area for years.

Adults can travel long distances between feeding grounds and nesting beaches. One female tagged at Buck Island in the US Virgin Islands was tracked about 1,870 km (1,160 mi) to feeding grounds off Nicaragua, and hawksbills from the Solomon Islands travel 800–1,650 km (500–1,000 mi) to waters off Australia. Others, such as Hawaiian hawksbills, stay within their island chain.

Nesting, life cycle and lifespan

Females return to nest on beaches in the general area where they hatched, usually every 2–3 years, though the interval can be 1–5 years. They mate in shallow water off the nesting beach. In most places the nesting season falls between April and November, but it varies; in the Seychelles, for example, most nesting happens from about September to February.

Hawksbills prefer small, secluded beaches, often with a rocky approach, and usually dig their nests high on the beach under or among vegetation. A female crawls ashore at night, digs a nest with her back flippers and lays an average of 130–160 eggs, a process that takes one to three hours. She nests three to five times in a season, about two weeks apart.

The eggs incubate for about two months, and, as in other sea turtles, the sand temperature decides the hatchlings’ sex: warmer nests produce more females (see does temperature decide a turtle’s sex?). Hatchlings emerge at night and head for the brightest horizon, normally the open sea.

Hawksbills grow slowly. NOAA estimates that they reach maturity at about 20–35 years, depending on food supply and region; Caribbean turtles may mature sooner than those in the Indo-Pacific. Their maximum lifespan is not known, but they are long-lived and estimated to live 50–60 years or more. Very few hatchlings survive long enough to breed.

Predators and threats

Eggs and hatchlings face many predators, including crabs, seabirds, raccoons, mongooses, rats, feral pigs, dogs and fish. Adults have few natural enemies thanks to their hard shell, but they can be killed by tiger sharks and other large sharks, saltwater crocodiles and large groupers.

People are by far the biggest threat. Hawksbills have been killed for centuries for their shell, and in many places their eggs and meat are still taken despite legal protection. Other threats include accidental capture in gillnets and on fishing hooks, coastal development and seawalls, artificial lights that confuse nesting females and hatchlings, collisions with boats, plastic and other pollution, and the decline of coral reefs from bleaching and disease. Rising sea levels can flood nests, and warming sand may produce too few males.

Conservation status

The IUCN Red List classifies the hawksbill as Critically Endangered, a status it has held since 1996; the most recent global assessment found that the population had declined by more than 80% over the last three generations, roughly 100–135 years. The species has been listed in Appendix I of CITES since 1977, which bans international commercial trade, and as Endangered under the US Endangered Species Act since 1970.

There are signs of hope. Some protected nesting populations, for example in parts of the Caribbean, the Seychelles and the Arnavon Islands of the Solomon Islands, have increased after decades of conservation. In the eastern Pacific, where hawksbills were feared almost extinct, about 700 females now nest each year from Mexico to Peru. For the full story, see why is the hawksbill critically endangered?

Hawksbills and people: the tortoiseshell trade

For thousands of years, people have carved hawksbill scutes into combs, jewelry, eyeglass frames, boxes and furniture inlays. The material is called tortoiseshell in English and bekko in Japan, which was the largest importer until it stopped imports in the early 1990s. A 2019 study of historical trade records estimated that about 9 million hawksbills were killed for the international tortoiseshell trade between 1844 and 1992.

Today, buying or importing tortoiseshell products is illegal in many countries, including the United States and the European Union, yet souvenirs made from hawksbill shell still turn up in some tourist markets. Living hawksbills are now worth more to many coastal communities as an attraction for divers and snorkelers than they ever were as trinkets.