A Guide to the Amphibians
and Reptiles of California

Frog and Toad Behavior and Life History


observation link


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
  california toads  
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.
california toad california toad california toad
california toad eggs california toad tadpoles california toad tadpoles
california toad tadpoles california toads california toad
Miscellaneous Frog and Toad Observations
chiricahua leopard frog spadefoot gb spadefoot
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
sierran treefrog cascades frog toad
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
frog California Red-legged Frog  
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.
Red-spotted Toad tadpoles Red-spotted Toad tadpoles  
It's a hard life for amphibians in the desert where water needed for egg-laying is scarce. These Red-spotted Toad tadpoles were stranded in evaporating water from an overflowing pond in a spring-fed desert oasis. The small black patch at the bottom of the picture on the left is the same group of tadpoles shown close-up in the picture on the right. Most of these tadpoles were still alive, so the water had only recently dried up and stranded them, most likely dooming them to dessication. Maybe the tadpoles hatched in the pond and were forced out when it overflowed, or perhaps some eggs were laid in shallow pools of water outside the pond which evaporated before the tadpoles could transform into toads.  
Nictitating Membrane Covering Eyes
eye eye gb spadefoot
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.

Yosemite Toad Yosemite Toad American Bullfrog
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.
Scaphiopus couchii Couch's Spadefoot Scaphiopus couchii Couch's Spadefoot Scaphiopus couchii Couch's Spadefoot Amplexus
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 ca treefrog nor pac treefrog
California Treefrog Baja California Treefrog Pacific Treefrog
green treefrog Gray Treefrog mexican treefrog
Green Treefrog
climbing on class
Gray Treefrog
climbing on glass
Mexican Treefrog
climbing on class
  baja california treefrog  
  Baja California Treefrog
climbing on class
foot spadefoot African Clawed Frog
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.
Aberrant or Unusually-Marked Frogs
Due to unusual skin coloring, markings, skin texture, or other unusual physical features or deformities, these frogs do not look like typical members of their species.
Red-spotted Toad Red-spotted Toad california toad
This adult California Toad found in a desert canyon in San Diego County, is missing some of its normal pigmentation, but it's not an albino because the eyes are dark.
© Cameron Ruland
This tiny juvenile toad was found at Darwin Falls, Inyo County, where hypbrids with Red-spotted Toads - Bufo punctatus have been found. While it resembles a California Toad, it appears to be a hybrid since it lacks a dorsal stripe and has less oval and more rounded parotoid glands, similar to the Red-spotted Toad. © Ceal Klingler
california toad california toad california toad
Patternless adult California Toad
© Nick Esquivel
Very pale adult California Toad from a San Diego County Desert valley - looking similar to a Red-spotted Toad. © Steve Bledsoe
American Bullfrog American Bullfrog American Bullfrog
Froglet, 10/09/16 Juvenile frog, 06/23/17 Juvenile frog, 07/16/17
Three pictures from a series of pictures of a developing leucistic American Bullfrog Tadpole found in Germany.
All photos © Michael Waitzmann. See the full series here.
Sierran Treefrog Sierran Treefrog Sierran Treefrog
This recently-metamorphosed juvenile Sierran Treefrog from Contra Costa County has a rear leg deformity that is most likely caused by a parasite that is hosted by a snail before it attaches itself to a tadpole. Such deformities are becoming more common and researchers are trying to determine if there are environmental factors which are favoring the parasites or which make the frogs more susceptible to them.
This juvenile Sierran Treefrog from San Mateo County has a deformed fifth leg.
© Rory Doolin.
Sierran Treefrog Sierran Treefrog foothill yellow-legged frog
A pink and blue juvenile Sierran TreefrogYolo County © Lori Grennan
A blue juvenile Sierran Treefrog found in a squash blossom in El Dorado County
© Dennis Johnson
Adult Foothill Yellow-bellied Frog with a dark mottled pattern, Shasta County
© Michael A. Peters
foothill yellow-legged frog Cascades Frog Tadpoles Cascades Frog Tadpoles
Bright red juvenile Foothill Yellow-bellied Frog from Del Norte County Two leucistic Cascades Frog tadpoles,
© Ryan Aberg
Cascades Frog tadpoles
Bottom/Left: Leucistic
Top/Right: Normally-pigmented
© Ryan Aberg
Northern Pacific Treefrog Sierra Nevada Yellow-legged Frog foothill yellow-legged frog
Leucistic adult Pacific Treefrog, Humboldt County © Nathan McCanne This adult Sierra Nevada Yellow-legged Frog has an unusual pigment condition, possibly leucism or it might be piebald.
© Isaac Chellman
Red-backed form Foothill Yellow-legged Frog, Humboldt County
© Steven Krause
Red-spotted Toad Red-spotted Toad foothill yellow-legged frog
Adult male and female California Toads in amplexus in a San Diego County desert riparian area. The male appears to be leucistic or xanthic. © Taylour Unzicker Red-backed form Foothill Yellow-legged Frog, Humboldt County
© Steven Krause
California Red-legged Frog foothill yellow-legged frog foothill yellow-legged frog
This unusually bright-orange-colored tiny juvenile California Red-Legged Frog has recently gone through metamorphosis, but has not yet lost the remnant of its tail. © John Kunna Unusually-marked aduilt Foothill Yellow-legged Frog, Humboldt County
© Nathan McCanne
This abnormally-yellow Rocky Mountain (Woodhouse's) Toad was photographed in Riverside County
© Max Roberts
California Red-legged Frog American Bullfrog American Bullfrog
Melanistic adult American Bullfrog, Santa Clara County © Yuval Helfman Two melanistic sub-adult American Bullfrogs
found in a Butte County pond. © Roxanne Mulder
California Red-legged Frog Cascades Frog Cascades Frog
Unusually gray nearly-patternless adult California Red-Legged Frog, Santa Barbara County © Max Roberts This unusually yellow-orange juvenile Cascades Frog, found at a high-elevation lake in Trinity County, appears to be missing its dark pigment, including the dark pigment normally found in the eyes. © Lauren Clark
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
American Bullfrog Tadpole  
Tadpole without legs, in water, 3 weeks before "Day 1"  
American Bullfrog Tadpole  
Tadpole with legs, in water, 1 day before "Day 1"  
American Bullfrog Juvenile American Bullfrog Juvenile American Bullfrog Juvenile
Metamorph, out of water, Day 1
Metamorph, Day 2 Metamorph, Day 3
American Bullfrog Juvenile American Bullfrog Juvenile American Bullfrog Juvenile
Metamorph, Day 4 Metamorph, Day 5 Metamorph, Day 6
American Bullfrog Juvenile American Bullfrog Juvenile American Bullfrog Juvenile
Metamorph, Day 7 Metamorph, Day 8 Metamorph, Day 9
American Bullfrog Juvenile American Bullfrog Juvenile American Bullfrog Juvenile
Juvenile, Day 14 Juvenile, Day 29

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