Sea turtles rely on various diets depending on their species; these may include herbivorous, omnivorous or carnivorous diets.
Rehabilitated turtles must be fed a diet tailored specifically to their species, condition and age to prepare them for release into the wild.
Green turtles feed on seagrasses and seaweeds, using their sharp, serrated beaks to tear through seagrass and remove algae off rocks. Leatherbacks prefer jellyfish as prey and will dive deep during the day to find them.
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Herbivore
Adult green turtles feed on aquatic vegetation such as algae, sea grasses and seaweeds. Their serrated beaks resemble saws to cut through the rough surfaces of these plants for digestion in their stomachs – their bodies efficiently breaking down cellulose unlike most reptiles can do.
Flatback sharks possess serrated jaws which enable them to consume an array of marine invertebrates including jellyfish, sea cucumbers, soft corals, shrimp, crabs and molluscs. In addition, their mouth and throat contain spine-like projections called papillae that enable them to grasp and pierce soft prey items.
Scientists can investigate turtle diets through various techniques, such as snorkel and SCUBA diving, gut content analysis, fecal samples and stable isotope analysis. Unfortunately, rising ocean levels have caused some sea turtles to mistake floating plastic as food and starve themselves to death as the chemical compounds contained within it enter their system and make them sick.
Omnivore
Reptilians developed wide, long ribs without an outer shell; while modern turtles possess protective carapace and plastron shells for protection. While most species are omnivorous, some such as Hawksbill and Leatherback sea turtles specialize in gelatinivory by subsisting on jellyfish and sponges exclusively.
Hawksbill turtles use their beak-like mouth to prod into crevices on coral reefs to search for sponges. In addition, these marine birds consume algae, crustaceans, and fish eggs for sustenance.
Green hatchlings are omnivorous, feeding on both meat and plant life; as adults they become vegetarian. With sharp serrated beaks that resemble saws, adult green turtles use their beaks to scrape algae off rocks while shredding seaweed, seagrass, roots of kelp plants, etc. As other sea turtles do, Green hatchlings digest their food using acid; however they have also been known to accidentally consume plastic marine debris floating in the ocean such as balloons that endanger rescue turtles who usually succinctly succinctly due to consuming these items which is an issue when rescue turtles often die due to this behavior.
Carnivore
Adult green sea turtles prefer eating only plants, while hatchlings may consume all forms of food. Their saw-tooth beaks are ideal for scraping algae off rocks while their tongues contain downward-curving spines known as papillae which help transport food directly to their stomachs.
Hawksbill and leatherback turtles are more carnivorous and feed on jellyfish, tunicate mollusks, crustaceans and sea sponges for sustenance. Their shape allows them to access crevices on coral reefs where these tasty gelatinous invertebrates reside.
Tragically, loggerhead and green turtles are hunted for their meat and eggs by hunters across many countries as delicacies. At night hunters scour beaches looking for nesting females before killing them with hammers, knives or nets and using body parts such as oil, cartilage shell and skin as food sources – thus underscoring why protecting all types of sea turtle species is imperative.
Spongivore
The Hawksbill (Eretmochelys imbricata), one of the most abundant marine turtles on coral reef systems, feeds almost exclusively on sponges. Their feeding habits contribute to maintaining high levels of diversity and coral cover on reefs due to competition between sponges and scleractinian corals for space; with predation by Hawksbills helping reduce competition between them for resources while stimulating coral growth.
Adult green sea turtles (Chelonia mydas) are herbivores and prefer eating algae, seaweed and the seagrasses that flourish near coral reefs. Their finely serrated beak allows them to scrape algae off rocks with ease.
Loggerheads (Caretta caretta) are herbivores as well, feeding on bottom-dwelling organisms like whelks, clams and mollusks in addition to jellyfish, fish, shrimp and coral. Their two cusps on either jaw enable them to pierce through tough shells of these creatures – thus driving loggerheads deeper into nesting beaches in search of food! In search of jellyfish however they will venture even deeper, and have even been known to travel across entire ocean basins in pursuit of this prey!
