Yosemite toad facts, pictures and information.
The Yosemite toad is an endangered amphibian found only in California, USA. The species lives in the Sierra Nevada mountain range, and has a number of adaptations for living at high altitudes.
Since the 1970’s the Yosemite toad population has undergone a sharp decline. The species was given endangered status by the IUCN (International Union for Conservation of Nature) in 1996.
Yosemite Toad Facts at a Glance
- Other Name(s): Yosemite park toad
- Scientific name: Anaxyrus canorus
- Type of Animal: Amphibian
- Animal Family: Bufonidae
- Where Found: California, USA
- Snout-Vent Length: 5 to 7.5 cm (1.77 to 2.95 in)
- Conservation Status: Endangered
Meet the Yosemite Toad: Introduction
The Yosemite toad is a member of the family Bufonidae. Members of this family are known as ‘true toads’. Like all true toads, the Yosemite toad has warty skin and a poison gland – known as a parotoid gland – located behind each eye.
The Yosemite toad is closely related to three other species: the black toad (Anaxyrus exsul), the western toad (Anaxyrus boreas) and the Amargosa toad (Anaxyrus nelsoni). Collectively, the four species are known as the ‘boreas group’.
The second part of the Yosemite toad’s binomial name Anaxyrus canorus means ‘tuneful’. This refers to the male Yosemite toad’s melodious call that some say resembles a bird’s call.
You can hear the toad’s call in the video below, which also features footage of the toads in the wild…
What Does The Yosemite Toad Look Like?
The Yosemite toad is a bulky, medium-sized toad with large warts, irregularly shaped parotoid glands, and dark brown eyes with horizontal pupils.
The difference not just in size, but also in color, between male and female Yosemite toads is greater than that of any other North American frog or toad.
Male Yosemite Toad
Female Yosemite Toad
Females are the larger of the two sexes. They are gray or brown with large, black blotches bordered with white.
Males are brighter – their color ranges from yellow-green to olive – and more uniform in color.
Juvenile toads have a white stripe running along the middle of their backs, but otherwise resemble small adult females. As the frogs mature the stripe fades. The female’s black spots expand, while those of the male shrink and disappear.
Yosemite toad tadpoles are black all over and measure from 10 to 37 mm (0.4 to 1.5 in). The eyes are positioned on the top of the head, and the snout is short and blunted.
Where Is The Yosemite Toad Found?
The Yosemite toad is found only in the state of California, USA. A small region of the state, spanning only around 240 km (150 mi), of the Sierra Nevada mountain range, is home to the world’s entire Yosemite toad population.
The amphibian’s range extends north from the Spanish Mountain in Fresno County to the Blue Lakes region in the Alpine County.
Zoom in to find these locations on the map below…
Yosemite Toad Habitat
Yosemite toad habitat includes wet mountain meadows and the borders of forests. This high-altitude specialist is found at elevations of between 1,400 and 3,600 m (4,800 and 11,900 ft.).
Although adult Yosemite toads spend most of their time on land they are rarely found more than 90m (300 ft.) away from a permanent body of water.
Breeding takes place in shallow snowmelt pools, at the edges of ponds and lakes, in flooded areas and in slow-moving streams.
Yosemite Toad Facts: Behavior & Hibernation
The Yosemite toad is most active during the day. This ectothermic (cold-blooded) species will often bask in the sun in order to warm up.
At night, the toad shelters in rodent burrows, in dense vegetation, under logs and rocks or in root tangles.
The Yosemite toad uses the same types of shelter for hibernation. Hibernation begins between September and October, and is possibly triggered by the first freezing night-time temperatures. The toads usually emerge from hibernation between April and May.
The species is solitary and, outside of the breeding season, non-territorial. Individuals tend to stick to the same foraging and breeding sites.
Adaptations for High-Altitude Living
The Yosemite has a long lifespan, with males living up to 12 years, and females up to 15 years. This may be to ensure the population’s survival through seasons in which adverse weather causes poor breeding conditions.
Unlike many other frogs and toads, the Yosemite toad is diurnal (active during the day). This behavior may have evolved due to the relative cold of the toad’s mountain habitat.
The dark color of the toad’s eggs and tadpoles – and of the female’s skin – may help to raise body temperature.
The Yosemite toad selects areas of shallow – and therefore warmer – water as breeding sites. The tadpoles also congregate in shallow areas.
Yosemite Toad Life Cycle
Mating takes place between May and July. Males arrive at the breeding sites several days before the females and will stay in the area for up to 2 weeks. Females will usually only remain at the breeding sites for a few days.
The males establish temporary territories in the shallow water and begin calling to attract females. The advertisement call is a high-pitched, flute-like trill.
Depending on the population density at the breeding site, the males may also actively move around searching for females instead of joining a chorus. (A ‘chorus’ is a group of singing frogs.)
When a female approaches, the male grasps her and holds on to her back while she searches for a suitable egg-laying location. The male fertilizes the dark-colored eggs as they are being laid.
The eggs are laid in single or double strings, or occasionally in clusters. One female may lay between 1,500 and 2,000 eggs. The eggs hatch in 10 to 12 days, and metamorphosis takes place in 7 to 9 weeks after hatching.
- You can find out more about the life-cycle of amphibians here: Amphibians: The Ultimate Guide
What Do Yosemite Toads Eat?
Both adult and juvenile Yosemite toads eat a wide variety of invertebrates, including: beetles, flies, mosquitoes, caterpillars, ants, spiders, centipedes, millipedes, wasps and spider mites.
During summer, insects in the order Hymenoptera (which includes ants, bees, wasps and sawflies) may make up as much as 80% of the toad’s diet.
The Yosemite toad is an ambush predator, flipping its sticky tongue out to catch its prey.
The aquatic larvae (tadpoles) feed on algae and detritus.
Yosemite Toad Predators
Yosemite toad tadpoles are vulnerable to predation by mountain yellow-legged frogs (Rana muscosa), diving beetles, robins and dragonfly naiads.
Both larvae and juvenile toads may fall prey to garter snakes. Some birds, such as common ravens, may prey on the adult toads.
The coloration of the Yosemite toad may provide some protection from predation: the males are camouflaged in the shallow, silty waters of the breeding pools, while the females blend into their environment in rocky upland areas.
The amphibian’s main means of defense is the foul-tasting toxic substance produced by the large parotoid glands positioned on either side of its neck.
Is The Yosemite Toad Endangered?
The Yosemite toad is rated ‘Endangered’ by the IUCN.
Dramatic declines in Yosemite toad numbers have been observed over several decades. The toads have disappeared from many locations in which they used to be present.
A 2004 report found that in just 10 years the entire population may have shrunk by over 50%.
Potential causes for the species’ decline include:
- Disease: The toads are vulnerable to several pathogens. These include the chytrid fungus that causes the lethal disease chytridiomycosis in amphibians.
- Habitat degradation: The presence of livestock can alter Yosemite toad habitat negatively via trampling and deterioration of water quality.
- Droughts: Droughts can cause high tadpole mortality if the breeding ponds dry out before the larvae have undergone metamorphosis.
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