California giant salamander
The California giant salamander is a species of salamander in the family Ambystomatidae. D.ensatus is endemic to California, in the western United States. Terrestrial adults spend most of their time on land in close proximity to fresh water. In contrast, during breeding, in larval development, and neoteny they spend their time inside shallow fresh water. The species once additionally included individuals now belonging to the species D.aterrimus and D.tenebrosus, under the common name Pacific giant salamander, which now refers to the whole genus.
Taxonomy
The Pacific giant salamander was thought to consist of three geographic populations: an Idaho group, a group in northern California, and a group in Oregon and Washington. In 1989 genetic studies showed that the D.ensatus populations consisted of three species: the Idaho giant salamander in Idaho, and two highly divergent species with a narrow hybrid zone in California, the coastal giant salamander and the California giant salamander . A fourth species of Dicamptodon, Cope's giant salamander '', lives on the Olympic Peninsula, Washington.Distribution and habitat
Geographic range
The California giant salamander is endemic to Northern California and lives up to primarily in damp, coastal forests including coast Douglas fir and California coast redwood in both montane and valley-foothill riparian habitats. They tend to be common where they occur. The adult terrestrial form is found under surface litter and in tunnels, while the adult aquatic and larval forms are found mainly in cool, rocky streams and occasionally in lakes and ponds.It is found in two isolated regions. The first range includes Sonoma, Napa, and Marin Counties, southwestern Lake County, western Glenn County, and southern Mendocino County. The other documented region is south of the San Francisco Bay from central San Mateo County to southern Santa Cruz County plus western Santa Clara County. The California giant salamander does not occur in the East Bay, forming a gap between these two populations. There is an unconfirmed sight record from Big Sur in Monterey County, approximately 75 miles to the south of the documented population in the Santa Cruz area.
Habitat preference
The natural habitats of D.ensatus are damp temperate forests and clear, cold freshwater streams, ponds, and lakes.Commonly found near hiding spaces like large rocks or wood, within close proximity to leafed debris, small shallow forms of water, and moist soil near banks.
Studies have found the California giant salamander to be a good indicator species for the health of headwater streams.
Adult salamanders were found near deteriorating waterway infrastructure, however more research is needed to be determine if this is a preferred habitat.
Description
The adult California giant salamander can reach in total length.Like most salamanders, the California giant salamander has four toes on the front feet and five toes on the back feet. The California giant salamander's tail is approximately 40% of the total length of the salamander and is laterally compressed. The head, back, and sides of the salamander have a marbled or reticulate pattern of dark blotches on a light brown or brassy-colored background. They have a broad head with a shovel-like snout and a fold of skin across the throat called the gular fold. The eyes are medium in size and have a brass-flecked iris and a large black pupil. This species is one of the few salamanders capable of vocalizing.
Behavior and ecology
Activity
The California giant salamander is predominantly nocturnal.Diurnal activity can occur after the first rains following dry spells, in maintained rain, and during mating season when within of a water source.
Diet
Terrestrial adults search for prey such as snails, slugs, insects, other invertebrates, small mice, shrews, possibly reptiles, and other amphibians under surface objects and in tunnels. Aquatic adults and larvae eat aquatic invertebrates, fish, snakes, and other amphibians.Predators
The California giant salamander is preyed upon by the American water shrew and the Sierra garter snake.Reproduction and development
Breeding
The California giant salamander breeds from March to May, with egg-laying peaking in May.Some occurrences of breeding in autumn have been reported. Both seasons have extremely maintained wet conditions, which are important for sexually mature adults. Terrestrial adults will migrate out from under rocks and logs to find puddles and streams to find mates.
Reproduction
Reproduction of California giant salamanders are observed to be in aquatic environments like small puddles and fresh water streams. Mothers will guard their egg clutch for months until they hatch, to protect from predation.Egg deposition
Fresh California giant salamander eggs are white and are smaller than.Eggs are concealed several feet below the surface in cold, slowly flowing water often beneath rocks and coarse woody debris in stream bottoms.