A Guide to the Amphibians
and Reptiles of California

Frog and Toad Behavior and Life History

Click on a picture for a larger view

Frogs Eating	Movement	Sounds	Reproduction	Predators
Camouflage and Defense	Clustering	Toes and Feet	Miscellany	Life Cycle
		Eggs

These are pictures and videos that illustrate some of the interesting interesting behavior and or natural history of frogs and toads from California and around the world. Follow the links on the name of each species to find more pictures and information about it.
The Life Cycle of the California Toad


This short video shows the life cycle of the California Toad, from the late winter breeding season when frenzied males call and compete and pair up with females who lay long strings of eggs, to tiny black tadpoles just emerged from the eggs then developing and forming huge feeding masses, to the tiny toads, recently-transformed from tadpoles, massing together around the pond edge then dispersing on their own, to an adult toad moving about on its own, as it will remain until the next breeding season. To see more video of each stage, from breeding, to eggs, to tadpoles, to metamorphs, to adult phase, click on the thumbnails below.




Miscellaneous Frog and Toad Observations


Frogs shed their skin just like snakes and lizards. In this short video you can see the skin pulled from the front toes and rear legs of a Chiricahua Leopard Frog and swallowed. The frog uses all four of its legs to pull the old skin off and push it towards its mouth. The mouth is opened and closed to pull the skin into the mouth. This one minute video was cut down from about five minutes, but the shedding took much longer.	Spadefoot tadpoles hatched in shallow rain pools need to grow and transform quickly when there is no rain and the pools evaporate. Here you can see tadpoles in the water, recently-metamorphosed tailed juveniles on the land and in the water, and some views of a shallow rain pool as it dries up.	Spadefoots spend most of their lives buried in mud or sand. This short video shows a Great Basin Spadefoot digging into sandy soil and burying itself. © Julie Nelson

This juvenile treefrog from San Mateo County has a deformed fifth leg. © Rory Doolin. Because of their thin permeable skin, amphibians are one of the first indicators of environmental disturbances, some of which can cause malformations. Learn more about frog deformities here.	Cascades Frogs live high in the mountains and have a high tolerance for cold. They emerge from hibernation and breed as the snow and ice is melting. This frog is sitting at the edge of the ice covering a mountain pond, while other frogs call and breed nearby.	Toad in the Hole

The Lowland Burrowing Treefrog lives in the desert, emerging from underground with the summer rain to breed and feed before going back underground. In order to survive during times of drought when moisture underground is scarce, this frog forms a cacoon around its body made of several layers of outer skin, which forms a barrier to keep its body moisture from evaporating. When the rains come again, the frog breaks free of the skin, sheds it, and eats it, not wasting any source of nourishment.	This adult California Red-legged Frog has a transmitter attached to its waist. After it is released, the frog can be found later by using an antenna with a radio receiver that can track the transmitter. This way the frog's movement and behavior can be studied for part of the year. Mature frogs use fat stored in their thighs to produce gametes as the breeding season nears. When the thighs have been significantly reduced in size, the transmitters will slip off the frogs. © Neil Keung Research covered under Federal permits and State Parks permits.

Nictitating Membrane Covering Eyes

A CanadianToad with the nictitating membrane on its eye partially closed	A Green Frog showing a partially-closed nictitating membrane.	This Great Basin Spadefoot is using its nictitating membrane, a translucent membrane, also called a third eyelid, to moisten its eye. © Ceal Klingler

Sexual Dimorphism
Animals that are sexually dimorphic are those where the males differ from the females in appearance. Some species have minor differences in body size that are not immediately observable in the field, but others have differences in color or pattern or in the size of the tympanum, which can let you easily determine the sex by sight.

An adult female Yosemite Toad (left) has heavy dark blotches on a light background, while an adult male (right) is pale yellowish green or olive above, with few or no dark blotches.		The tympanum (the circle behind the eye) of an male American Bullfrog (left) is much larger than the eye. The tympanum of an adult female (right) is the same size as or smaller than they eye.

Adult female	Adult male	Adult male (top) and Adult female
An adult female Couch's Spadefoot has a heavy pattern of dark markings while and adult male does not.

Toes and Feet
Some frogs have special pads on their toes that act like suction cups to help them climb steep surfaces, even glass.

California Treefrog	Baja California Treefrog	Northern Pacific Treefrog

Green Treefrog climbing on class	Gray Treefrog climbing on glass	Mexican Treefrog climbing on class

	Baja California Treefrog climbing on class

Most frogs, including this American Bullfrog, have large webbed hind feet.	Spadefoots and some toads have hardened spades on the backs of their feet. These spades help them dig underground. This picture shows the small black spade on one of the hind feet of a Great Basin Spadefoot	The claws on the hind webbed feet of the African Clawed Frog are used to grasp and tear at its food.

Development of a Tadpole Into a Juvenile Frog
The following series of pictures shows an American Bullfrog tadpole in full metamorphosis - it begins to breathe air, gradually loses its tail, and transforms into a juvenile frog with the body of an adult. Click here to see a larger view

Tadpole without legs, in water, 3 weeks before "Day 1"

Tadpole with legs, in water, 1 day before "Day 1"

Metamorph, out of water, Day 1	Metamorph, Day 2	Metamorph, Day 3

Metamorph, Day 4	Metamorph, Day 5	Metamorph, Day 6

Metamorph, Day 7	Metamorph, Day 8	Metamorph, Day 9

Juvenile, Day 14	Juvenile, Day 29

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