The grey tree frog complex includes the Eastern Grey Tree Frog (Hyla versicolor) and Cope’s Grey Tree Frog (Hyla chrysoscelis), two visually identical species sharing the same ecological niche. These small, arboreal amphibians are native to the eastern half of North America, ranging from the southern United States up into Canada. As obligate carnivores, adult grey tree frogs are strictly insectivorous, relying entirely on live prey for sustenance. Understanding their natural diet is fundamental to replicating the proper nutritional profile in captivity.
The Grey Tree Frog’s Natural Prey
In the wild, the grey tree frog is an opportunistic predator whose diet is largely composed of small, arboreal invertebrates. Since they spend most of their time high up in trees and shrubs, their food sources are primarily insects and arthropods found on bark and leaves. Common prey items include moths, flies, mites, and small spiders, which they encounter while perched on vertical surfaces.
Their feeding is constrained by the size of their mouth, meaning all prey must be swallowed whole. The diet includes flying insects, beetle larvae, harvestmen, small slugs, and ants. These frogs often congregate around artificial lights, such as windows and porch lamps, where the concentration of insects offers an abundant food supply. The composition of their meals shifts depending on the local environment and time of year, demonstrating a flexible foraging strategy driven by availability.
Providing Food in Captivity
Replicating a diverse and nutritionally complete diet in captivity requires providing commercially available feeder insects. The primary food source for adult grey tree frogs is crickets, supplemented with other soft-bodied invertebrates like waxworms, mealworms, and small silkworms. Juvenile frogs require smaller prey, such as flightless fruit flies, until they are large enough to consume pinhead crickets.
To ensure the frogs receive adequate nutrition, feeder insects must be fortified through “gut loading,” which involves feeding them a high-quality, calcium-rich diet for 24 to 48 hours before feeding. Gut-loading fills the insect’s digestive tract with beneficial nutrients, which are then passed on to the amphibian.
In addition to gut loading, the insects must be dusted with vitamin and mineral supplements before being fed. Calcium powder, often containing Vitamin D3, is necessary to prevent metabolic bone disease, which results from an improper calcium-to-phosphorus ratio. Calcium should be dusted onto the prey at every feeding, while a multivitamin supplement containing Vitamin A should be applied once or twice a month to ensure a complete nutritional profile.
Hunting Behavior and Feeding Mechanics
Grey tree frogs are classic sit-and-wait predators that hunt primarily during the night. They use their camouflage to remain motionless on a surface, ambushing any suitable prey that wanders into striking range. This patient strategy conserves energy and is highly effective in their arboreal habitat.
The capture mechanism involves a rapid, ballistic projection of their tongue, which is attached at the front of the mouth. The tongue is coated in a specialized, viscoelastic saliva that quickly switches from a watery state to a thick, sticky one upon impact. This allows the frog to secure the invertebrate instantly before retracting it back into the mouth at high speed.
Once the prey is secured, the frog uses a unique swallowing mechanism that involves its eyes. The frog retracts its large eyeballs down into the skull, which helps create pressure inside the mouth. This action physically pushes the food from the sticky tongue and down the throat toward the esophagus, facilitating deglutition. Vomerine teeth on the roof of the mouth also help to hold the captured prey securely until it is fully swallowed.