California Toad
(Old Name: Western Toad)
Anaxyrus boreas halophilus
Size
Adults grow to 2 – 5 inches from snout to vent
Appearance
A large and robust toad with dry, warty skin.
No cranial crests are present.
Parotoid Glands are oval and well-developed.
Pupils are horizontal.
Color and Pattern
The ground color is Greenish, tan, reddish brown, dusky gray, or yellow.
Rusty-colored warts are set on dark blotches.
There is much dark blotching above and below, becoming all dark at times.
The throat is pale on both males and females.
A light stripe is usually present on the middle of the back.
Male/Female Differences
Males are usually less blotched than females and have smoother skin.
Females are larger than males and more stout.
During the breeding season, males have dark nuptial pads on the thumbs and the inner two digits of the hands.
Males are usually less blotched than females and have smoother skin.
Females are larger than males and more stout.
During the breeding season, males have dark nuptial pads on the thumbs and the inner two digits of the hands.
Young
Young have no dorsal stripe immediately after transformation.
The bottoms of their feet is bright orange or yellow.
Larvae (Tadpoles)
Tadpoles are dark brown with eyes inset from the edges of the head.
The tip of the tail is rounded.
They grow to about 2.25 inches (5.6 cm) in length before undergoing metamorphosis.
Life History and Behavior
Activity
Active in daytime and at night. Often diurnal after winter emergence, becoming nocturnal in the summer after breeding.
Movement
Slow moving, often with a walking or crawling motion along with short hops.
Defense
This toad uses poison secretions from parotoid glands and warts to deter predators. Some predators are immune to the poison, and will consume toads. Still other predators such as ravens have learned to avoid the poisons by eating only their viscera through the stomach.
Territoriality
Male Western Toads are not territorial except when breeding. Amplexing males will kick away other males, and males may briefly fight other males at breeding sites.
Longevity
Western Toads in Colorado have been reported living at least 9 years. I have received a report of a toad raised from a tadpole that is 21 years old and still alive (9/14).
Voice
Male California Toads do not have a pronounced vocal sac, but they do make a call during breeding aggregations. Their call has been described as a high-pitched plinking sound, like the peeping of a chick, repeated several times. Since it is not made to attract distant females, the call is not very loud when compared to the call of the sympatric Pacific Treefrog (or similar treefrog species.) The sound of a group of males calling has been compared to the sound of a distant flock of geese.
Calls are produced at night and during the day during the short breeding season. Males make their call primarily when they are in close contact with other males. Rather than being advertisement calls made to attract females, these calls are generally considered encounter or aggressive calls, or release calls, which serve to maintain territory and spacing between males. The calls may also serve other purposes – a lone male toad has been observed calling. It could also be possible that female toads are attracted to the sounds of male encounter calls, and can judge a male’s condition by his call, similar to the function of an advertisement call.
Unreceptive females may also produce a release call when grasped on the back by a male. Males and females sometimes make a release call when grabbed across the back by a human hand.
Diet and Feeding
Diet consists of a wide variety of invertebrates.
Prey is located by vision, then the toad lunges with a large sticky tongue to catch the prey and bring it into the mouth to eat.
Tadpoles consume algae and detritus, including the scavenged carrion of fish and other tadpoles (including Caifornia Toad tadpoles – Herpetological Review 38(2), 2007 178-9)
Breeding
Reproduction is aquatic.
Fertilization is external, with the male grasping the back of the female and releasing sperm as the female lays her eggs.
The reproductive cycle is similar to that of most North American Frogs and Toads. Mature adults (4 – 6 years old) come into breeding condition and migrate to ponds or ditches. Males and females pair up in axillary amplexus in the water where the female lays her eggs as the male fertilizes them externally. The adults leave the water and the eggs hatch into tadpoles which feed in the water and eventually grow four legs, lose their tails and emerge onto land where they disperse into the surrounding territory.
Breeding can occur any time from January to early July, depending on the elevation, winter snow levels, or rainfall amounts, taking place shortly after toads emerge from their hibernation sites and migrate to the breeding wetlands. Scent cues are used to find the way to the breeding site. In some areas, breeding occurs after snowmelt when breeding ponds refill with water. Amplexus and egg-laying takes place in still or barely moving waters of seasonal pools, ponds, streams, and small lakes.
Eggs
Eggs are laid in long strings with double rows, averaging 5,200 eggs in a clutch.
Fresh eggs contain some of the toad’s toxin to protect them from predation, but this poison decreases over time.
Eggs hatch in 3 to 10 days, often longer in the colder waters of higher elevations.
Tadpoles and Young
Tadpoles are dark brown and grow to about 2.25 inches (5.6 cm) in length before undergoing metamorphosis.
Large schools of tadpoles often feed together in shallow water.
Tadpoles enter metamorphosis in 30 – 45 days, usually in summer or early fall, depending on water temperature – colder water delays metamorphosis.
In years of extreme winter weather, especially at higher elevations, metamorphosis might be only a few weeks before snow begins to accumulate again.
When in the process of metamorphosis, many tadpoles are often seen in aggregations at the edge of a pond in various stages of metamorphosis.
After most tadpoles undergo metamorphosis, large numbers of newly-transformed toads are often seen hopping around the edges of the water.
They may stay and spend the winter at the border of their natal wetland, or they may disperse to nearby sites away from the pond.
Habitat
Inhabits a variety of habitats, including marshes, springs, creeks, small lakes, meadows, woodlands, forests, and desert riparian areas.
In the spring and early summer, toads are often found at the edge of water, sometimes basking on rocks and logs. At other times of the year they are also found farther from the water where they spend much of their time in moist terrestrial habitats.
Toads use rodent holes, rock chambers, and root system hollow as refuges from heat and cold.
Comparison with Boreal Toads
A. b. halophilus has fewer dark blotches on the belly than A. b. boreas.
The head of A. b. halophilus is also wider with larger eyes with less distance between the upper eyelids, and
the feet are also smaller than A. b. boreas. (Stebbins)
Comparison with Sympatric Arroyo Toads
Adults
Arroyo toads typically have a light stripe or V across the head and eyelids which is lacking on California Toads.
Mature California Toads typically have a pale dorsolateral stripe (a pale light stripe down the middle of the back) which is lacking on Arroyo Toads.
Juveniles
Juvenile Arroyo Toads show the pale V between the eyes, pale spots on the sacral humps, yellow tubercles, and are unmarked ventrally.
Juvenile Calfornia Toads have no pale V or pale sacral hump spots, rust-colored turbercles, a pale dorsolateral stripe, and are marked with dark spots ventrally.
Juvenile Arroyo toads are typically found fully exposed in direct sunlight on the sandy banks of the natal creek.
Juvenile California toads are typically found dug into wet sand at the edge of the creek, or in shade under vegetation.
Tadpoles
Mature California Toad tadpoles appear dark with light mottling while mature Arroyo Toad tadpoles appear light with dark mottling.
Arroyo Toad tadpoles tend to remain motionless more than California Toad tadpoles. About a quarter of a small group of Calfornia Toad tadpoles will be active at any moment, while only a few individuals in a small group of Arroyo Toad tadpoles will be moving at any moment.
Metamorphosing Arroyo Toad tadpoles show the pale V between the eyes, pale spots on the sacral humps, and yellowtubercles.
Metamorphosing California Toads are darker with no pale V or sacral hump coloring, and rust-colored tubercles.
