Understanding Reptile Diets

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Updated on October 24, 2019

Reptiles are a diverse group of animals, and therefore have very different feeding habits—just as you wouldn't expect a zebra and a whale to have similar diets, so you shouldn't expect the same for box turtles and boa constrictors. Learn about the favorite foods of the five major reptile groups: snakes, turtles and tortoises, crocodiles and alligators, lizards, and tuataras.

Crocodiles and Alligators

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Crocodiles and alligators are "hyper carnivorous," meaning that these reptiles obtain most or all of their nutrition by eating fresh meat. Depending on the species, the menu can include mammals, birds, amphibians, other reptiles, insects, and pretty much anything that moves on two, four, or a hundred legs. Interestingly, crocodiles and alligators evolved from the same family of prehistoric reptiles (the archosaurs) that also spawned dinosaurs and pterosaurs, which helps put their bloodthirsty dinner preferences into perspective.

Turtles and Tortoises

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Yes, they will occasionally snap at your fingers, but the fact is that most adult turtles and tortoises prefer eating plants to eating live animals. The same doesn't apply to hatchlings and juveniles: Testudines need a lot of protein to form their shells, so younger individuals are more inclined to eat grubs, snails and small insects. Some sea turtles subsist almost exclusively on jellyfish and other marine invertebrates, while others prefer algae and seaweed. (By the way, you can make a pet tortoise sick, or cause deformities in its shell, by feeding it too much animal protein!)

Snakes

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Snakes, like crocodiles and alligators, are strictly carnivorous and feed on pretty much any living animals—vertebrate and invertebrate alike—that are appropriate to their size. Even a small snake can swallow a mouse (or an egg) whole, and the larger snakes of Africa have been known to feed on adult antelopes. One curious fact about snakes is that they're unable to bite or chew their food; these reptiles open their jaws extra-wide to slowly swallow their prey, fur and feathers included, and then regurgitate the parts that can't be digested.

Lizards

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Most, but not all, lizards (technically known as squamates) are carnivores, the smaller ones feeding mostly on small insects and terrestrial invertebrates like snails and slugs, and the larger ones on birds, mice, and other animals (the largest lizard on earth, the Komodo dragon, has been known to scavenge the flesh of water buffaloes). Amphisbaenians, or burrowing lizards, wield their crushing bites on worms, arthropods, and small vertebrates. A small number of squamates (like marine iguanas) are herbivorous, feeding on aquatic plants like kelp and algae.

Tuataras

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Tuataras are the outliers of the reptile family: They superficially resemble lizards, but can trace their ancestry back 200 million years to a family of reptiles known as "sphenodonts." (There is only one species of tuatara, and it's indigenous to New Zealand.) In case you're tempted to adopt a tuatara as a pet, be sure to keep a steady supply of beetles, crickets, spiders, frogs, lizards, and bird eggs (as well as bird hatchlings) on hand. Tuataras are known for their powerful bites—which, combined with their reluctance to let go of their prey, makes them easier to visit at the zoo than in your own backyard.