Reptiles & Amphibians comparison

Bullfrog vs Cane Toad: Key Differences Explained

The short answer

Both are large amphibians that have become serious invasive species, but they differ in form and mechanism. The American bullfrog is a smooth-skinned, strongly aquatic frog that damages native fauna mainly by eating it and by carrying disease. The cane toad is a dry, warty terrestrial toad with large parotoid glands whose potent skin toxin kills native predators that try to eat it.

The main difference

The bullfrog is an aquatic predator that eats and out-competes native species, while the cane toad is a terrestrial toad whose skin toxin poisons the predators that attack it.

They are the two best-known amphibian invaders, and comparing them shows that ecological damage can come from very different mechanisms — predation and disease against toxicity.

At a glance

Comparison of Bullfrog and Cane Toad across 6 dimensions, with an interpretation of each difference.
What differs	Bullfrog	Cane Toad	What it means
Body form	Smooth moist skin, long powerful hind legs, strongly aquatic	Dry warty skin, shorter legs, terrestrial and heavy-bodied	The classic frog-versus-toad contrast, in two animals of similar size.
Parotoid glands	Absent	Very large and prominent behind the eyes, secreting a potent toxin	The glands are the single most important feature for understanding the cane toad's impact.
Native range	Eastern and central North America	Central and South America	Both have been introduced far outside these ranges, in several cases deliberately.
Main invasive mechanism	Predation on native species, competition, and carrying amphibian disease	Poisoning of native predators that attempt to eat it	Two very different routes to the same outcome of native population decline.
Habitat	Permanent ponds, lakes, slow rivers and marshes	Open and disturbed ground, gardens, roadsides and farmland	The cane toad's tolerance of dry disturbed habitat is central to how fast it spreads.
Call	A deep resonant call often likened to a distant cow	A sustained low trill, repeated at length	Calls are useful for detecting and monitoring both species in survey work.

Body form: BullfrogSmooth moist skin, long powerful hind legs, strongly aquatic
Cane ToadDry warty skin, shorter legs, terrestrial and heavy-bodied
The classic frog-versus-toad contrast, in two animals of similar size.
Parotoid glands: BullfrogAbsent
Cane ToadVery large and prominent behind the eyes, secreting a potent toxin
The glands are the single most important feature for understanding the cane toad's impact.
Native range: BullfrogEastern and central North America
Cane ToadCentral and South America
Both have been introduced far outside these ranges, in several cases deliberately.
Main invasive mechanism: BullfrogPredation on native species, competition, and carrying amphibian disease
Cane ToadPoisoning of native predators that attempt to eat it
Two very different routes to the same outcome of native population decline.
Habitat: BullfrogPermanent ponds, lakes, slow rivers and marshes
Cane ToadOpen and disturbed ground, gardens, roadsides and farmland
The cane toad's tolerance of dry disturbed habitat is central to how fast it spreads.
Call: BullfrogA deep resonant call often likened to a distant cow
Cane ToadA sustained low trill, repeated at length
Calls are useful for detecting and monitoring both species in survey work.

How they are related

Both are anurans, so both are frogs in the biological sense, but they sit in different families. The American bullfrog is a true frog in Ranidae; the cane toad is a true toad in Bufonidae. Their contrast is a good illustration of how the everyday frog and toad labels map onto real family-level differences in skin, glands and lifestyle.

Telling them apart

Skin and glands settle it. The bullfrog is smooth and moist with a prominent circular eardrum behind the eye and long powerful hind legs. The cane toad is dry and warty with very large parotoid glands sloping back from behind the eyes, a heavy body and short legs. Habitat also differs: bullfrogs stay at water, cane toads roam far from it.

Smooth, moist, long-legged, at the water's edge, diving when disturbed: bullfrog. Dry, warty, short-legged, with large glands behind the eyes, far from water: cane toad. Both are large amphibians and both are invasive well outside their native ranges, but they harm ecosystems in fundamentally different ways.

Habitat and distribution

Bullfrogs need permanent water and are found at pond, lake and slow river margins, where they remain close to the edge and dive when disturbed. Cane toads are far more tolerant, occupying gardens, roadsides, farmland and disturbed ground, and needing water only to breed. That tolerance is a large part of why cane toads spread so rapidly through introduced ranges.

Diet and ecological role

Both are generalist predators that eat essentially anything they can swallow. Bullfrogs take insects, other frogs, small fish, snakes, rodents and birds, and their appetite for native amphibians is a major part of their impact. Cane toads take invertebrates and small vertebrates, and unusually among amphibians will also consume carrion and pet food left outdoors.

Behaviour

Bullfrogs are largely solitary, with males holding calling territories at the water's edge through the breeding season and defending them physically. Cane toads gather in numbers around lights and food sources and breed in large aggregations, producing very large egg strings. Both are chiefly nocturnal, and both are long-lived and highly fecund, which compounds their invasive potential.

People and these animals

Both were spread deliberately by people. Bullfrogs were introduced for food and then escaped from farming operations, while cane toads were introduced repeatedly as a failed agricultural pest control measure, most famously in Australia, where the toads did not control the target beetle and instead became a major problem themselves. Both are now the subject of substantial and difficult control programmes.

Conservation context

Neither is threatened in its native range, and both are managed as invasive species elsewhere. Their significance for conservation is as a pressure on other species rather than as species at risk, and control programmes for both are ongoing and only partially successful.

What they have in common

Both are large anurans that have become serious invasive species outside their native ranges.
Both are generalist nocturnal predators that eat almost anything they can swallow.
Both are long-lived and highly fecund, producing very large numbers of eggs.
Both were spread deliberately by people and both are now the subject of control programmes.

Key differences

The bullfrog is smooth-skinned and aquatic; the cane toad is warty and terrestrial.
Cane toads have large parotoid glands secreting a potent toxin; bullfrogs have none.
Cane toads harm ecosystems by poisoning predators; bullfrogs by eating native species and spreading disease.
Bullfrogs need permanent water, while cane toads tolerate dry disturbed ground.
They come from different families — Ranidae and Bufonidae.

Where people go wrong

Assuming both damage ecosystems the same way, when one poisons predators and the other eats prey.
Treating the cane toad as venomous, when its glands secrete a poison that is not injected.
Thinking a toad is not a frog, when toads sit inside the same order.

Frequently asked questions

Why are cane toads so damaging where they have been introduced?

Because of their toxin rather than their appetite. Large parotoid glands secrete compounds potent enough to kill native predators that attempt to eat them, and in places where no local animal evolved alongside a toxic toad, predators have no avoidance behaviour. Populations of native predators have declined sharply along the invasion front in Australia. The toads also breed prolifically and tolerate dry, disturbed habitat.

How do bullfrogs damage ecosystems differently?

Chiefly by eating native wildlife and carrying disease. A large bullfrog will consume almost any animal it can swallow, including native frogs, fish, snakes and small birds, and it out-competes native amphibians for space and food. Bullfrogs also carry chytrid fungus, which they tolerate relatively well while it devastates other amphibian species, so their spread can spread the disease as well.

Are both of these actually frogs?

Yes. Both are anurans, so both are frogs in the biological sense, and toad is a descriptive label rather than a taxonomic rank. The cane toad is a true toad in the family Bufonidae, with the dry warty skin, short legs and parotoid glands that characterise that family, while the bullfrog is a true frog in Ranidae. Their differences are real but do not make one a non-frog.

Why were these species introduced in the first place?

For agriculture and food. Cane toads were moved repeatedly as a biological control agent intended to reduce beetle pests in sugar cane, an attempt that failed because the toads did not reach the beetles and instead spread rapidly through the wider landscape. Bullfrogs were farmed for meat and escaped or were released from those operations. Both are frequently cited examples of introductions with severe unintended consequences.

Read the full profiles

Sources and methodology

How this comparison is built: FaunaHub comparisons are assembled from the sourced animal profiles behind them rather than written as standalone claims. Figures such as size, mass, and lifespan are typical ranges that vary by subspecies, population, region, sex, age, and — where relevant — whether an animal lives in the wild or under human care, so they are presented as ranges rather than fixed values. Where a common name covers a group rather than a single species, the page says so instead of implying a species-to-species match. Conservation status changes over time and should be confirmed against the current IUCN Red List. Dimensions that could not be supported from the underlying profiles are omitted rather than filled in.

What this page does not do: it does not rank the two animals, predict the outcome of a confrontation, or present either one as stronger, smarter, or better. It is not veterinary, medical, first-aid, handling, capture, hunting, or pest-control guidance. For an animal in your care, or any situation involving injury, contact a qualified veterinarian, your local wildlife authority, or emergency services.

Sources and further reading

Authoritative references used for general educational context. External links open in a new tab. These sources do not endorse FaunaHub.

UniversityAmphibiaWeb — University of California, Berkeley — Authoritative database of amphibian biology and conservation
UniversityAnimal Diversity Web — University of Michigan Museum of Zoology — Peer-edited reference accounts for animal species
Wildlife referenceIUCN Red List of Threatened Species — Authoritative source for current conservation status
UniversityAnimal Diversity Web — Rhinella marina (cane toad) — University of Michigan species account
ReferenceBritannica — Cane toad (Rhinella marina) — Editor-reviewed encyclopedia entry

Last updated: 2026-08-04