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arroyo toad
The arroyo toad (''Anaxyrus californicus'') (syn. ''Bufo californicus''), is a stocky, blunt-nosed, warty-skinned species of toad, long. It has horizontal pupils, and is greenish, grey or salmon on the dorsum with a light-colored stripe across the head and eyelids. It has light sacral and mid-dorsal patches, large, oval and widely-separated parotoid glands, and weak or absent cranial crests.
The juvenile of this species are ashy-white, olive or salmon on the dorsal side, with or without black spotting. It has red-tipped tubercles on its back.
==Habitat==
''Anaxyrus californicus'' prefers sandy or cobbly washes with swift currents and associated upland and riparian habitats, in Southern California and Baja California. An arroyo is also called a wash; it is a dry creek or stream bed. It fills and flows after sufficient rain, but only temporarily during specific seasons. The arroyo toad inhabits these areas alongside rivers with shallow pebble-like rocks near sandy terrains. Adults take refuge into the sandy soil for protection and shelter. Most importantly the sandy soil enables the female adults to safely lay their eggs. Areas with very little to no vegetation are the primary target. The arroyo toad is a terrestrial and freshwater species. They are prominently nocturnal with a breeding season that revolves around the months of late winter and early spring after seasonal rains. This time is the best for males to forage for breeding supplies. Their eggs are laid at the calling sites of males which take place near shallow gravelly areas near sandy terraces as mentioned earlier. The male may stay latched onto the female for days until she disperses the eggs so he can fertilize them. Outside the breeding season the arroyo emphasizes its terrestrial characteristics, traveling over a kilometer from their normal stream sites. During the dry season the arroyo toad goes into a state of hibernation called aestivation to prevent dehydration. This dormant state normally takes place within the soil or clay-like sand and is from August to January. Due to deforestation they live in small isolated populations. These populations change due to climatic conditions, fires and human cause. When its suitable habitat is disturbed it is hard to estimate an accurate population size. The isolated populations of northern and southern Baja has risen excitement as to whether there would be any genetic diversity among the different populations. Different clades have been supported for the species inhabiting Southern Baja. At least three sub species of the Arroyo Toad inhabit Southern Baja, California.
The arroyo toad is evaluated as Endangered on the IUCN Red List of Threatened Species because of habitat destruction.
抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』
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