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American Bullfrog (Lithobates catesbeianus)

The American Bullfrog is a prominent amphibian native to North America. During the mating season, which spans from May to July, male bullfrogs are notably vocal, their calls resonating across ponds and lakes. Typically found in shallow waters, bullfrogs are less frequently observed than Green Frog (Lithobates clamitans) but are a fascinating subject for wildlife enthusiasts.

At a Glance – American Bullfrog

Why is the American Bullfrog such a well-known amphibian in North America?

Because of its size, deep call, and presence in many ponds and lakes across the continent.

The American Bullfrog stands out as one of North America’s largest and most vocal frogs. Its deep “jug-o-rum” call is a familiar sound in summer wetlands. Found in ponds, lakes, and marshes, it’s a species people often hear before they see, making it a recognizable symbol of warm, still evenings near the water.

Where can I spot American Bullfrogs in Quebec?

They’re found in several parks around the Greater Montreal Area.

In southern Quebec, bullfrogs inhabit shallow ponds and marshes, especially in parks such as Parc Mont Saint-Bruno, Parc Angrignon, and Parc de la Frayère. They prefer quiet waters with reeds or aquatic plants where they can stay hidden but close to the surface.

How can I tell the difference between an American Bullfrog and a Green Frog?

Look at the crest line running behind the eye — it ends differently in each species.

The Green Frog (Lithobates clamitans)’s crest runs along its back, while the Bullfrog’s stops just behind the eardrum (tympanum). This subtle feature is one of the easiest ways to distinguish the two. Bullfrogs also tend to be larger and have deeper, more resonant calls.

Why are bullfrogs sometimes considered invasive?

Because they’ve been introduced to new regions where they outcompete native species.

Originally native to eastern North America, bullfrogs were brought to other parts of the world for food and aquaculture. In these new environments, their adaptability and appetite allow them to dominate local ecosystems, often reducing native amphibian populations. Managing their spread has become an important conservation challenge in several countries.

Best Locations and Seasons for Sightings

In a selection of ponds in the Greater Montreal Area and Southern Quebec, from late spring to early autumn, I observe them less frequently than the Green Frog (Lithobates clamitans). Typically, I spot them remaining motionless in the shallow water amidst the reeds along the pond's shore.

Interestingly, Lac des Bouleaux, Parc Mont Saint-Bruno, is home to both Green Frog (Lithobates clamitans) and American Bullfrog (Lithobates catesbeianus), though the two species are well separated. To spot Bullfrogs, check the area to the left of the floating platform. The Green Frogs, on the other hand, tend to gather near the opposite corner of the lake, further along the same pathway.

"x" indicates the species was observed, while "-" indicates no observation. Lack of observation doesn't necessarily imply that the species is absent. Data is derived from my park visit journals.

Identification and Similar Species

At first glance, distinguishing a bullfrog from a Green Frog (Lithobates clamitans) can be challenging. Observe the crest that starts above the eye and extends around the eardrum, leading to the front legs. In Green Frog (Lithobates clamitans), this crest runs along the back to the hind legs.

Photography Tips

Thanks to its tendency to remain motionless even when approached carefully, this species can be photographed with a macro lens — my favorite way to capture it. See profile photo.

Captured Moments

Videos are hosted on YouTube. Click on a thumbnail to watch it.

All content on this page — including photos, videos, and field audio recordings — was created by Karl-Heinz Müller, a Montréal-based wildlife filmmaker, sound recordist, and photographer. Founder of MUUUH and Québec Sauvage, he has spent over a decade documenting Canada’s natural habitats through immersive soundscapes and wildlife films. Learn more about Karl-Heinz

Last updated: 2025-10-30