Frogs’ dietary habits are nuanced, especially when considering their different life stages. While many associate them with catching flies, adult frogs are carnivores, primarily consuming other animals. However, their offspring, known as tadpoles, typically exhibit different feeding behaviors.
What Adult Frogs Eat
Adult frogs are obligate carnivores, meaning their diet consists almost entirely of other animals. Their opportunistic nature leads them to prey on a wide variety of invertebrates. Common prey items include various insects such as flies, mosquitoes, beetles, crickets, grasshoppers, moths, slugs, snails, and worms. Larger frog species can expand their diet to include bigger prey. This can involve small vertebrates like fish, other amphibians, small rodents, and even small birds. Their diet is largely influenced by what is available in their habitat and what they can overpower.
How Frogs Catch Their Prey
Frogs employ a specific method to capture their food, typically using an ambush hunting strategy where they wait for prey to come within striking distance. Their keen eyesight is particularly adept at detecting movement, which triggers their predatory response.
Once prey is spotted, a frog rapidly extends its specialized tongue, attached at the front of its mouth. This tongue is coated in highly adhesive saliva that possesses shear-thinning properties, allowing it to become less viscous upon impact to envelop the prey and then become stickier to secure it. The entire process occurs in a fraction of a second. After securing the prey, many frog species retract their eyeballs, which helps to push the food down their throat into the esophagus.
The Tadpole Exception
The dietary habits of frogs undergo a significant transformation from their larval stage to adulthood. Most tadpoles are herbivorous, primarily consuming algae and other plant matter found in their aquatic environments. They use specialized mouthparts to scrape algae off surfaces or filter plant material from the water.
As tadpoles mature and prepare for metamorphosis, their diet can shift, with some species becoming omnivorous, consuming small organic debris, insect larvae, or carrion. In conditions of high population density or limited food, some tadpoles may even exhibit carnivorous behavior, preying on smaller or weaker siblings. This dietary change during metamorphosis is accompanied by a restructuring of their digestive system, transitioning from long intestines suited for digesting plant matter to the shorter, simpler digestive tracts of carnivorous adult frogs.