Sea turtle underwater

Sea turtles are ancient reptiles inhabiting tropical and subtropical oceans, playing a vital role in marine ecosystem balance.

About this subject

Sea turtles belong to the order Testudines and have existed for over 100 million years, dating back to the age of dinosaurs. Of the seven extant species, five are found in Brazil: the loggerhead (Caretta caretta), green (Chelonia mydas), hawksbill (Eretmochelys imbricata), olive ridley (Lepidochelys olivacea), and leatherback (Dermochelys coriacea). These species can be distinguished by shell shape, scute count, and color patterns.

The life cycle of sea turtles is marked by impressive migrations. After hatching on sandy beaches, hatchlings instinctively head to the sea, where they spend years drifting in ocean currents, feeding on plankton and small organisms. As adults, many turtles return to the same beaches where they were born to lay eggs, traveling thousands of kilometers. This phenomenon of natal philopatry is one of the most fascinating in marine biology, guided by Earth's magnetic field.

Diet varies by species: the green turtle is herbivorous, consuming algae and seagrasses, while the hawksbill specializes in sponges, helping control competition on coral reefs. The loggerhead prefers crustaceans and mollusks, and the leatherback feeds on jellyfish. This dietary diversity makes sea turtles crucial for ecosystem health, from maintaining seagrass beds to balancing prey populations.

Unfortunately, all sea turtle species are threatened with extinction, classified by the IUCN as Vulnerable, Endangered, or Critically Endangered. Major threats include bycatch in fishing nets, plastic pollution (which they mistake for food), degradation of nesting beaches due to unregulated tourism, and illegal hunting for meat and eggs. Conservation programs like Projeto Tamar in Brazil work to protect nests, rehabilitate animals, and educate the public, contributing to population recovery.

Frequently Asked Questions

How many species of sea turtles are there in the world?

There are seven species of sea turtles: loggerhead, green, hawksbill, olive ridley, leatherback, flatback (Natator depressus), and Kemp's ridley (Lepidochelys kempii). The flatback is endemic to Australia, and Kemp's ridley is found mainly in the Gulf of Mexico.

Why are sea turtles important for the ecosystem?

They play vital ecological roles: green turtles control algae and seagrass growth, hawksbills help maintain coral reef health by preying on sponges, and leatherbacks regulate jellyfish populations. Additionally, unhatched eggs provide nutrients for coastal vegetation.

How can I help conserve sea turtles?

Reduce single-use plastics, participate in beach cleanups, avoid disturbing nests or hatchlings, support organizations like Projeto Tamar, choose seafood from sustainable sources, and avoid products made from turtle shell. Report stranded turtles to local wildlife authorities.