A Guide to the Amphibians
and Reptiles of California

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Frog and Toad Behavior and Life History - Reproductive Behavior

Frog and Toad Behavior and
Life History -
Main Page

Reproductive Behavior

Male frogs and toads typically call until a female comes into their territory and then they quickly jump onto the back of the female and hold on. The male stays on the female until she lays her eggs and he fertilizes them. This behavior is called Amplexus. Males are smaller than females and have thicker and stronger front legs to help them hold on to her back, and they even develop special grasping pads on one or more fingers of each hand to help their grasp. These are called Nuptial Pads. Males can get so excited that they will sometimes grab onto other males, other species of frogs, and even other animals, such as fish. Sometimes several males compete for the same female, forming a ball of males with a female in the middle. This can be dangerous to the female if she cannot get to the surface to breathe.

A nuptial pad on front foot of an adult male Boreal Toad.

Great Plains Toads

Gulf Coast Toads

Columbia Spotted Frogs

Sierra Yellow-legged Frogs

Couch's Spadefoot

American Toads

This video shows a male and a female Western Spadefoot in amplexus underwater in a breeding area of a rocky creek bed in San Joaquin County. You can also see some eggs by the pair and floating nearby. (The first shot is of the female after the male left her.)

California Toads in amplexus

California Toads in amplexus, with female laying eggs.

Two male California Toads attempt to steal the female from a pair in amplexus.

Yosemite Toads in amplexus with the female depositing her eggs

A congregation of breeding adult California Toads © Joyce Gross

This video shows a Northern Red-legged Frog breeding habitat with eggs.

Red-spotted Toads

Cascades Frogs

Male California Toads searching for females will sometimes go after anything that moves. These California Toads appear to be attempting amplexus with a catfish. © Andy Hatch

California Treefrogs in amplexus

Adult Baja California Treefrogs in amplexus © Mike Pecora

Pacific Treefrogs in amplexus
© Spencer Riffle

Northern Red-legged Frogs in amplexus © Spencer Riffle

Foothill Yellow-legged Frogs amplexus
© Janjaap Dekker

Foothill Yellow-legged Frogs in amplexus next to an egg mass in a creek.
© egret.org / Audubon Canyon Ranch

Scaphiopus couchii Couch's Spadefoot Amplexus

Couch's Spadefoots in amplexus

Couch's Spadefoots in amplexus and a solo male

Colorado Desert Toads in amplexus
© 2005 Jason Penny

Black Toads in amplexus

Arroyo Toads in amplexus
© James R. Buskirk

Southern Orange-eyed Treefrogs in amplexus in Australia

Arroyo Toads in amplexus. © Brett Badeaux.

This gravid adult female Arroyo Toad is in a stream in San Diego County where she is waiting to find a male so she can lay her eggs and have him fertilize them. © Emily Mastrelli

Arizona Treefrogs in Amplexus

Sierran Treefrogs in amplexus
© Bill Stagnaro

These videos showbreeding behavior at the shallow outlet of a pond in Contra Costa County where at least 8 solo males and 10 pairs in amplexus were observed in the area.

This video shows some of the sounds and activities of Black Toads on the breeding grounds.

In this video, a group of male Black Toads thrash around in the water trying to wrestle away a female away from another male.

A short video of non-stop ultimate toad-fighting action with a gang of Black Toads trying to steal away females from other males, chasing them around the pond.

Adult male tailed frog* showing his tail-like copulatory organ. This organ, an extension of the cloaca, is used to transfer sperm into the female's cloaca during amplexus. She then holds the fertilized eggs for 9 or 10 months when she swims under a large stone on the bottom of a fast-moving creek and attaches the eggs to the bottom of the stone. This internal fertilization strategy lets tailed frogs breed in fast-moving water without the eggs washing away, which would happen if they were laid and fertilized on the surface of the water.
* Ascaphus montanus

This adult Sierran Treefrog was found at an old Native American bedrock mortar site. These small treefrogs will breed in almost any pool of water if nothing larger is available, including mortar holes filled with rainwater, roadside rain puddles, and even in bowls of water left outside for dogs to drink from.
(Also seen in the water with it is a Horsehair Worm, and some Springtails.)
© Mark Gary

Adult Sierran Treefrog and eggs in a large Native American bedrock mortar hole in Contra Costa County.
© Mark Gary

Adult Arroyo Toads in amplexus, partially
buried in sand, San Diego County
© Andrew Borcher

Breeding Season Appearance

Breeding males develop a dark throat patch, which you can see on this Western Spadefoot. © Andrew Borcher

Adult male Sierran Treefrog
with a dark throat patch.

Calling adult male Baja California Treefrog. The throat patch enlarges and fills with air as a male makes his breeding calls.

Interspecific Amplexus

Sometimes male frogs and toads enter into amplexus with a female or even a male of a different species. This is called Interspecific Amplexus. When an invasive species is involved, such as the American Bullfrog below, it's one more example of how invasives are a threat to the native species.

Houston Toad in amplexus with a different species - a Gulf Coast Toad.

Adult Foothill Yellow-legged Frog in amplexus with an American Bullfrog in Nevada County © Tom Van Wagner

A California Toad attempts amplexus with a Western Spadefoot in San Diego County. © Andrew Borcher

Male California Toads in an Alameda County breeding pond, apparently attempting amplexus with a catfish.
© Andy Hatch

Adult male Arroyo Toad in amplexus with a California Toad in San Diego County
© Andrew Borcher

These California Red-legged Frogs are in amplexus with California Toads that share their ponds and breed at about the same time.

Adult Sierran Treefrog in amplexus with a California Newt in Contra Costa County. © Mark Gary

This picture shows the unusual venter to venter amplexus of a male Common Toad - Bufo bufo and a male Common Frog - Rana temporaria observed in Germany © Guntram Deichsel

Necrogamy

Sometimes male frogs and toads amplex a dead female. This is called Necrogamy.

A live adult male California Toad in amplexus with a dead female California Toad (necrogamy). The third pictures shows a male's typical amplexus hold around the females chest, holding her under the arms. © Jeff Ahrens

These misguided California Toads are attempting to breed with a dead toad. It's possible they found a dead female, but its also possible they suffocated or drowned her in their agressive competition to amplex her. © Mark Gary

Eggs of Frogs and Toads

Most North American frogs and toads lay eggs in water. After the eggs develop they hatch and become tadpoles.
Sometimes you can tell what sort of frog or toad laid the eggs by the appearance of the eggs, but typically you can only identify the family of frog or toad found in a particular area: Ranid frogs lay eggs in large rounded masses, Treefrogs and Chorus Frogs lay eggs in small round sacs, Toads lay eggs in long strings, etc. These are not the eggs of all frog families, only those for which I have pictures.

Toad Eggs

Western Toads lay their eggs in long strings.

Red-spotted Toads lay their eggs singly or in a small cluster.
Other North American toads lay their eggs in strings.

Black Toads lay their eggs in strings.

Eastern American Toad egg strings

Yosemite Toads lay their eggs in strings. The strings often get lumped together giving the appearance of one large mass of eggs. © Julie Nelson

Ranid Frog Eggs

American Bullfrogs lay their eggs in large floating masses in the summer.

Lowland Leopard Frog eggs

Leopard frogs lay eggs in large rounded masses. These were all laid by Northern Leopard Frogs.

Northern Red-legged Frog egg masses.

California Red-legged Frog egg masses.

Foothill Yellow-legged Frogs lay eggs in small masses.

Cascades Frog Eggs

Oregon Spotted Frog egg mass.

Columbia Spotted Frog egg masses.

Sierra Nevada Yellow-legged Frog egg masses

Chiricahua Leopard Frog egg mass

Treefrog and Chorus Frog Eggs

The three species of "Pacific Treefrogs" lay their eggs in rounded masses, that sometimes clump together.

Canyon Treefrog eggs

Arizona Treefrog eggs

Spadefoot Eggs

Couch's Spadefoot eggs

Great Basin Spadefoot eggs,
temporarily removed from water.

Egg masses of two frog species laid next to each other in the same pool:
Top - Baja California Treefrog eggs
Bottom - Western Spadefoot eggs
Riverside County © Nathan Kudla

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