Wildlife · Reptiles & Amphibians
American Bullfrog
The American bullfrog is the largest frog on the continent, and its deep, resonant call is one of the signature sounds of summer across North America. Ponds, lake edges, and slow-moving streams are prime habitat, making this an animal most families encounter without even planning for it. Learning to spot one and sit quietly enough to watch it hunt is one of the genuine pleasures of a warm-weather outing.
This page from Outside, the family adventure app, is a field-guide entry on the American bullfrog (Lithobates catesbeianus). It covers identification, the habitats and seasons where families most commonly encounter the species, notable behaviors worth watching in the field, two standout natural history facts suitable for kids, and respectful viewing etiquette. The page also addresses common family questions about handling, calls, and the bullfrog's role in its wetland ecosystem.
| Region | Continental United States |
|---|---|
| Habitat | Ponds, lakes, slow streams, marshes |
| Best season | Late spring through early fall |
| Activity time | Dawn, dusk, and after dark for calls |
| Experience level | All ages |
How to recognize it
The American bullfrog is hard to mistake once you know what to look for. Adults are olive green to brownish on top, often with faint mottling, and pale or yellowish on the belly. The body alone can reach six inches or more in length, and the hind legs stretch considerably farther. The easiest field mark is the tympanum, the circular disc just behind each eye. In males, that disc is noticeably larger than the eye itself. In females, it is roughly the same size as the eye. Both sexes have a ridge of skin that curves from behind the eye down and around the tympanum, but no dorsolateral ridges running down the back, which helps separate them from similar green frogs.
Where and when families find them
Bullfrogs turn up across almost the entire continental United States, from the Atlantic coast well into the West, where they have been introduced over the past century. They are creatures of still or slow water: farm ponds, lake margins, cattail marshes, and the quiet backwaters of rivers. If a body of water is large enough to support them through a cold winter and warm enough to breed in summer, bullfrogs are likely residents.
Prime viewing runs from late spring through early fall, when frogs are active at the water's surface during the day and calling hard after dark. Early morning and late afternoon on warm days are particularly productive. Look for a pair of eyes and nostrils resting just at the waterline, motionless, watching everything.
Behavior worth watching
Sit quietly at the water's edge for ten minutes and a bullfrog will often forget you are there. What follows is worth the patience. Bullfrogs are ambush hunters. They hold absolutely still, sometimes for long stretches, then explode forward to seize prey with a sticky, muscular tongue or simply lunge mouth-first. They eat almost anything they can swallow: insects, crayfish, small fish, other frogs, even the occasional small snake or duckling. Watching a bullfrog size up a dragonfly that lands nearby is a small drama that kids tend to remember.
Males are territorial and will wrestle competing males at the boundary of a prime calling spot. In summer, listen for the low, resonant call that gives the species its name, often described as sounding like the word "jug-o-rum" repeated across the water.
Two facts kids will repeat
First: the American bullfrog is the largest frog native to North America. A big individual can weigh close to a pound, which children find genuinely impressive once they try to picture it.
Second: bullfrog tadpoles take a remarkably long time to transform. In northern parts of the range, a tadpole may spend two full years in the water before it develops legs and climbs onto land as a froglet. That means the tadpoles overwintering in a cold pond near you are nearly the same age as your kindergartner.
Respectful viewing in the field
Bullfrogs are worth approaching with care, mostly because a spooked frog leaps into the water and the show is over. Move slowly, keep your shadow off the animal, and crouch down to water level when you can. A distance of six to ten feet is usually close enough for a good look and far enough to keep the frog calm.
Bullfrogs can be handled, but it is not recommended as routine practice. Their skin absorbs substances from human hands, including sunscreen and insect repellent, which can harm them. If a child does pick one up gently during a supervised pond study, make sure hands are clean and rinsed, and return the frog to the exact spot where it was found within a minute or two. Watching from shore nearly always produces a better experience anyway.
Its role in the wetland
In the ponds and marshes where they evolved, bullfrogs are mid-level predators that help regulate populations of insects, small fish, and other amphibians. They are also important prey for herons, otters, large fish, raccoons, and water snakes. Their tadpoles graze on algae and contribute to nutrient cycling in the water.
In parts of the American West and in other countries where bullfrogs have been introduced, they can outcompete native frog species, which is why wildlife managers pay close attention to their spread. In their native eastern and central range, though, they are a foundational part of a healthy wetland community and one of the most rewarding animals a family can learn to observe well.
Find a spot at the edge of a pond or slow stream and sit without talking for ten full minutes. Write down every living thing you notice, how it moved, and whether the bullfrog, if you spotted one, seemed aware of you.
Frequently asked questions
Is it safe to pick up an American bullfrog?
Bullfrogs are not harmful to handle, but their skin absorbs whatever is on your hands, so sunscreen and bug spray can injure them. If kids want a closer look during a pond study, make sure hands are clean and wet, keep the encounter brief, and return the frog to the same spot. Watching from a short distance is usually more rewarding and keeps the frog calm enough to observe natural behavior.
What does a bullfrog call sound like and when does it call?
The male bullfrog's call is a deep, booming rumble often described as sounding like 'jug-o-rum.' It carries a long distance across water. Males call most actively at night from late spring through midsummer, but you can hear them on warm afternoons too. If you hear a low, resonant bass note repeating from a pond after sunset, there is a very good chance a bullfrog is advertising its territory from the shallows.
How do you tell a bullfrog from a green frog?
Both species are common, green, and found at the water's edge, so families mix them up regularly. The key difference is the dorsolateral ridges, two raised folds of skin that run down the back of a green frog from behind the eye toward the tail. Bullfrogs lack these ridges entirely. Bullfrogs are also noticeably larger as adults, and the male's tympanum is much bigger than his eye, while in green frogs the two are closer in size.
What do bullfrogs eat?
Bullfrogs eat almost anything they can fit in their mouths. Their typical diet includes insects, worms, crayfish, small fish, and other frogs. Larger adults occasionally take small snakes, mice, or young birds. They are sit-and-wait predators, holding still until prey moves within striking range, then lunging with speed that surprises most first-time observers. Their appetite and patience make them fascinating to watch when you give yourself enough quiet time at the water's edge.