Hornworms are caterpillars of Manduca genus hawk moths. The hornworms commonly bred for feeding to reptiles, amphibians, and other exotic pets are usually tobacco hornworms, Manduca sexta.
In the wild, hornworms are frequently viewed as pests because they like to eat tomatoes and other garden variety plants. Wild hornworms should never be fed to pets, as their diet can make them toxic. Captive-bred hornworms are fed a toxin-free diet that makes them safe for pets to eat.