Description: Yosemite toads are medium-sized 2 to 3.3 inches (SVL) stocky toads, with females averaging larger than males. They generally lack cranial crests, but males will rarely have weakly developed ones. Their eyes have a dark brown iris with gold iridophores. In comparison with the closely related Western toad (A. boreas), the parotoid glands are large, narrowly spaced, and irregularly shaped (oval or flattened), less than one gland width apart. Like the parotoids, the eyes are spaced narrowly apart, usually less than the width of the upper eyelid. The warts are large, smooth, and the dorsal skin between warts is smooth as compared to the Western toad. It is the most sexually dichromatic species of anuran in North America, with males and females displaying strikingly divergent patterns and coloration at maturity. Females are dorsally covered in black blotches that have white or cream borders, with a tan, copper, or ruddy background; males are more uniformly colored, ranging from yellow-green, to olive drab, to greenish brown, sometimes with scattered black flecks near warts. Juveniles resemble adult females, except with a thin mid-dorsal stripe, which gradually fades during development (faster in males than females). A prominent mid-dorsal stripe is lacking in this species, unlike the Western toad. As juvenile males mature, their black blotches shrink and ultimately disappear, whereas they expand and reticulate in developing females.

Habitat: Yosemite toads occur from the upper montane into the subalpine zone, just below timberline. Their preferred habitat is wet, montane meadows and lakeshores, among lodgepole pines. During breeding season they may be found in pools, small, slow-moving streams, or boggy meadows.

Range: The Yosemite toad inhabits a 130 mile long segment of the central Sierra Nevada of California, from Alpine County to Fresno County, at elevations of 6,400 to 11,300 feet. MIGRATION: Yosemite toads do not really migrate, as their hibernation sites are within 100 meters from breeding ponds.

Found in these States: CA

Diet: Like other toads, Yosemite toads are ambush predators. They lunge at prey and open their mandibles, causing their sticky tongue to unfold, flip downward, and pull the animal into their mouths. Adult stomach contents have included: tenebrionid beetles, ladybird beetles, weevils, craneflies, mosquitos, caterpillars, carpenter ants, dragonfly naiads, centipedes, julid millipedes, and spiders. Juvenile stomach contents have included: ants, spiders, and wasps. Metamorph stomach contents have included: owl flies, flies, springtails, spider mites, and spiders. There appears to be an ontogenetic shift from eating mostly spider mites (metamorphs), to eating a mix of spider mites, spiders, and tiny wasps (2 months post-metamorphosis), to eating mostly larger hymenopterans, mostly ants (juveniles), to eating 80% hymenopterans, consisting of bees and wasp (adults). Tadpoles are grazers on detritus and algae, however it remains unclear whether they ingest those items, bacteria, rotifers, or something else. Tadpoles are also known to opportunistically scavenge conspecific tadpoles, Sierra chorus frog tadpoles, Belding's ground squirrels, and predaceous diving beetle larvae, as well as graze on lodgepole pine pollen grains.

Reproduction: Yosemite toads are explosive breeders (breeds within a short time period), migrating to breeding pools and flooded areas in late spring while snowbanks still veil the frozen meadows. They have been termed the "toad that stays on its toes" or "tiptoeing toad" due to their habit of crossing snowdrifts without touching their abdomen to the cold snow. Breeding time varies greatly with elevation and yearly snowpack (April to July), and depends on timing of snowmelt. Males arrive to breeding ponds synchronously when the meadow is ca. 50% covered in snow. Depending on the population density they will either join a breeding chorus by making an advertisement call to females, or will actively search for them. Their vocalization is a high-pitched, sonorous trill lasting an average of 2.6 seconds and repeated frequently. Males intermittently call from pool margins, under logs, or inside willows to attract females. When females arrive, they are immediately grasped in amplexus by one or multiple males as the males fight for a limited number of mating opportunities. Breeding sex ratios can be very skewed toward males since females breed less frequently than males, although both sexes typically do not breed in consecutive years. While in amplexus, females will lay one clutch of 1,000 to 2,000 eggs. Eggs hatch after 1 to 2 weeks, and the length of time depends heavily on ambient temperature and fluctuations in temperature. Females generally breed once and leave after 2-3 days, while males remain for 1 to 2 weeks.

Status: Yosemite toads are reported to have declined substantially in distribution and abundance across their restricted range. Although threats to persistence of the species are less understood than in other California amphibians such as the Sierra Nevada yellow-legged frog, the two most significant appear to be drought (increasing with climate change) and disease (primarily chytridiomycosis).

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