Ambystoma californiense

Geographic Range

Once considered to be subspecies of Ambystoma tigrinum , Ambystoma californiense is now considered to be their own distinct species. Ambystoma californiense are endemic to San Joaquin-Sacramento river valleys. California tiger salamanders live in woodlands and sage scrub communities of low altitude areas between the valleys and foothills of Tulare and Butte counties of Central California.

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Although California tiger salamanders are mostly limited to lower elevations (427 m), there have been documentations of sightings in elevations of 3,600 m. They require wet environments for reproduction. This includes but is not limited to vernal, ephemeral, rain-filled pools and sagponds. Although permanent aquatic habitats can support California tiger salamanders, they are rarely found in areas that can be inhabited by potential fish predators. Adults spend most of their time in underground burrows when they are not actively trying to breed. Because California tiger salamanders require wet areas for breeding, these burrows are typically found within 1 mile of their breeding grounds.

• Habitat Regions
• temperate temperate
• terrestrial terrestrial

• Terrestrial Biomes
• savanna or grassland savanna or grassland

• Aquatic Biomes
• temporary pools

Physical Description

Compared with most salamanders, California tiger salamanders are considered relatively large and broad with relatively curved snouts. Full grown males are on average about 30 mm longer than full grown females, where full grown males are on average 200 mm long and can grow up to 207 mm. Females grow up to 170 mm. However, both males and females have similar snout to vent lengths of 90 mm. California tiger salamanders have black colored eyes that project out of the head. The skin on their backs are black with usual spots of yellow, pale yellow, and white. On the underside, they are usually white, pale yellow, or yellow. Males can be differentiated by females by the swollen cloacas during breeding, their typical larger body sizes, and longer tails.

Although there is no data on the masses and resting metabolic rates (RMR) of adult California tiger salamanders, related species are on average 126 grams as adults and have RMRs of 0.002 Watts.

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• male larger

Development

Salamanders have two distinct life stages. The first life stage is when they are aquatic larvae, where the live in the same pools where they hatched. Following metamorphosis, salamanders become adapted to living in terrestrial environments and only go back to their former aquatic habitats to breed.

Ambystoma salamanders follow genetic sexual determination with sex chromosomes, where females are the heterogametic sex. Ambystoma californiense eggs hatch typically within ten to fourteen days after being laid. Upon hatching, larvae can be 11.5 mm to 14.2 mm in length. Typically, amphibians must attain a certain body size in order to metamorphose. California tiger salamanders achieve this size between 60 to 94 days from when they hatch in their breeding pools. Generally, the larger the breeding pools and the longer the duration before they dry out, the larger the larvae become. With larger larvae, salamanders metamorphose into larger juveniles. The entire process from start to finish for metamorphosis takes up to 10 weeks and the success is highly dependent on whether or not the breeding pool retains sufficient water. At the end of metamorphosis, the snout to vent length ranges from 41 to 78 mm.

• Development - Life Cycle
• metamorphosis metamorphosis

Reproduction

California tiger salamanders are usually 6 years old when they first migrate to breeding ponds, where less than half breed more than once. However, males are able to breed from the age of 2 and females at 2-3. California tiger salamanders migrate to their breeding ponds during the winter rainy months from November to May. Males often depart for the breeding ponds during the month of December where females would begin their migration in January. Earliest migrations have been observed to occur in October with the first rainfalls, but the majority move in December or later.

California tiger salamander migration for breeding is highly dependent upon rainfall volume and occurrence. In years where rainfall occurs late, females do not migrate to ponds and in years where there is sparse rains or droughts, males do not migrate to breeding ponds as well. In dryer breeding seasons, females are less likely to migrate to breeding ponds. In light of this, breeding can either occur in very short periods, winters of sparse rains, or over longer periods, where the breeding season has adequate amounts of rainfall.

California tiger salamanders typically breed in ponds that are uninhabited by fish predators. California tiger salamanders historically relied primarily on vernal pools for breeding but due to the destruction of their natural habitats, they have invaded pools constructed for cattle.

• Mating System
• polygynandrous (promiscuous) polygynandrous (promiscuous)

There is no current information on the reproductive behavior of Ambystoma californiense . However, it’s sister species, Ambystoma triginum reproductive behavior is highly characterized. Ambystoma triginum males have a preference for females who are larger because they often produce larger clutches. Female sexual selection are currently under investigation. Initiating copulation is an aggressive process in Ambystoma tigrinum , which is initiated with the male shoving the female.

Ambystoma tigrinum male-male interference strategies are dependent on the sizes of the males competing. Males that were larger than the ones that were copulating would often shove the smaller female, disrupting the copulating process. After interference, the interrupting male would then proceed to copulate with the female. Males that are smaller than the males that were actively copulating would exhibit female-like behavior. The female-mimic would align itself next to the copulating couple and proceed to deposit its spermatophore on the female eggs.

• Key Reproductive Features
• semelparous semelparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • external external
• oviparous oviparous

Besides the yolk that is provided in the egg, it is not known if there is any parental investment in Ambystoma californiense .

Lifespan/Longevity

California tiger salamanders reach sexual maturity rather early but do not begin to breed until they are about 5-6 years old. It has been reported that California tiger salamanders live past 10 years of age. However, less than 50% of those that live past 10 years old migrate back to their breading ponds.

There have not been extensive studies on the survivorship of Ambystoma californiense . In some small studies, A. californiense had survivorship rates of 4% that lived to maturity. In more extensive studies, a related species, Ambystoma talpoideum had survivorship rates of up to 20% of metamorphs from a single cohort that lived to maturity. In another related species, Ambystoma opacum , had survivorship rates ranging from 6% to 21% for metamorphs that lived to maturity.

In any ambystomatids , many mark-recapture studies have shown estimations of 60% survivorship among mature adult populations.

Behavior

Adult California tiger salamanders are typically found in rodent burrows in depths between 0.2 m and 1.36 m underground. They usually occupy burrows constructed by Spermophilus beecheyi and Thomomys bottae . It is speculated that Ambystoma californiense may share a commensal relationship with Spermophilus beecheyi , since Ambystoma californiense are often found in Spermophilus beecheyi occupied burrows. It is important for Ambystoma californiense to occupy the same burrows as Spermophilus beecheyi because Ambystoma californiense do not make their own burrows and without Spermophilus beecheyi , the burrows often collapse without their maintenance. Adult California tiger salamanders live underground during dry summers and estivation. When required, they leave to travel on the surface only during the night. Once breeding season begins, they migrate to their breeding pools and return to their mammal burrows once finished. Adults are able to move of up to speeds of 50.8 m/hour where juveniles can move of up to speeds of 30.9 m/hour.

• Key Behaviors
• fossorial fossorial
• motile motile
• migratory migratory
• aestivation

Home Range

In some studies, groups traveled up to 580 m from their breeding ponds to their burrows. However, 95% travel no more than 173 m from their burrows to the breeding pools. It is important to note that migration distances between burrows and breeding pools are related to how much precipitation there is during the migratory period. With more precipitation, California tiger salamanders can travel longer distances relative to when there is a less rain.

Communication and Perception

Communication through sound is not particularly important in intraspecific communication in salamanders. Salamanders are known to bark, hiss, and click but most of these sounds are to illicit anti-predator behavior. These noises are non-communicative and do not illicit consistent responses from other salamanders.

Because most salamanders live underground, it is suspected that coloration does not convey any intraspecies information. Tail wagging and body postures have been reported to denote aggressive behaviors in some species of salamanders.

The primary mode of communication between salamanders is through chemical signals. These chemicals can be excreted through pores of the skin or through fecal matter and sometimes even through glandular secretions. Chemical cues aid salamanders to identify sex and species. During the breeding season, males are able to produce pheromones from their swollen cloacas.

• Communication Channels
• visual visual
• acoustic acoustic
• chemical chemical

• Other Communication Modes
• pheromones pheromones

Food Habits

California tiger salamanders larvae feed on algae, crustaceans, and the larvae of some insects. When larger, California tiger salamanders transitions to eating larger prey, including tadpoles, aquatic insects, and aquatic invertebrates. In some conditions, Ambystoma larvae have exhibited cannibalistic tendencies induced by particular circumstances.

California tiger salamander adults appear to prey on arthropods while underground in burrows. After aestivation, adults prey on terrestrial invertebrates and following breeding, may emerge from their burrows during the night to prey on terrestrial invertebrates on the ground surface.

• Primary Diet
• carnivore carnivore
  • insectivore insectivore

• Animal Foods
• insects
• terrestrial non-insect arthropods

• Plant Foods
• algae

• Other Foods
• detritus detritus

Predation

Aside from living in burrows, the anti-predator adaptations of Ambystoma californiense are currently unknown.

Ecosystem Roles

California tiger salamanders rely heavily on Spermophilus beecheyi , a pest, for survival. These have ecological implications since conservation of California tiger salamanders would mean taking necessary precautions in controlling Spermophilus beecheyi without negatively impacting California tiger salamanders numbers.

California tiger salamanders prey on many arthropod species and help balance the invertebrate populations. Additionally, small birds, mammals, and turtles eat California tiger salamanders.

Economic Importance for Humans: Positive

Tiger salamanders ( Ambystoma tigrinum ), a related species, have been sold to fish markets as fish bait.

• Positive Impacts
• body parts are source of valuable material

Economic Importance for Humans: Negative

California tiger salamanders endangered status has lead to some developmental constraints in agricultural and commercial development. Its commensal relationship with Spermophilus beecheyi makes it particularly troublesome in trying to re-establish population levels because Spermophilus beecheyi is considered a pest species.

Conservation Status

Ambystoma californiense is listed as an endangered species under the California Endangered Species Act. Its habitat has been under severe destruction to human activity, specifically, in the urbanization and the resurrection of agricultural land. As a result, the burrows where adult California tiger salamanders live have been directly affected due to urbanization, killing salamanders, or at least trapping them underground.

Additional Links

AmphibiaWeb

Encyclopedia of Life

Contributors

Kevin Mesina (author), The College of New Jersey, Matthew Wund (editor), The College of New Jersey, Tanya Dewey (editor), University of Michigan-Ann Arbor.

References

Barry, S., B. Shaffer. 1994. The Status of the California Tiger Salamander (Ambystoma californiense) at Lagunita: A 50-Year Update. The Journal of Herpetology , 28/2: 159-164.

Holland, D., M. Hayes, E. McMillan. 1990. Late Summer Movement and Mass Mortality in the California Tiger Salamander (Ambystoma californiense). The Southwestern Naturalist , 35/2: 217-220.

Howard, R., R. Moorman, H. Whiteman. 1997. Differential effects of mate competition and mate choice on eastern tiger salamanders. Animal Behavior , 53: 1345-1356.

Joao, P. 2015. "AnAge: The Animal Age and Longevity Database" (On-line). Accessed November 13, 2015 at http://genomics.senescence.info/species/entry.php?species=Ambystoma_tigrinum .

Johnson, J., R. Thomson, S. Micheletti, B. Shaffer. 2011. The origin of tiger salamander (Ambystoma tigrinum) populations in California, Oregon, and Nevada: introductions or relicts?. Conservation of Genetics , 12: 355-370.

Lannoo, M. 2005. Amphibian Declines The Conservation Status of United States Species . Berkeley, California: The Regents of University of California. Accessed November 13, 2015 at http://amphibiaweb.org/cgi/amphib_query?where-genus=Ambystoma&where-species=californiense&account=lannoo .

Loredo, I., D. Van Vuren, M. Morrison. 1996. Habitat Use and Migration Behavior of the California Tiger Salamander. Journal of Herpetology , 30/2: 282-285.

Nafis, G. 2015. "A Guide to the Amphibians and Reptiles of California" (On-line). Accessed November 13, 2015 at http://www.californiaherps.com/salamanders/pages/a.californiense.html .

Salmon, T., W. Gorenzel. 2014. "University of California Agricultural and Natural Resources Statewide Integrated Pest Management Program" (On-line). Accessed November 13, 2015 at http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7438.html .

Trenham, P., B. Shaffer, W. Koenig, M. Stromberg. 2000. Life History and Demographic Variation in the California Tiger Salamander (Ambystoma californiense). Copeia , 2: 365-377.

Wells, K. 2007. The Ecology and Behavior of Amphibians . The University of Chicago Press, Chicago: The University Chicago Press.

Williams, R., A. DeWoody. 2009. Reproductive Success and Sexual Selection in Wild Eastern Tiger Salamanders (Ambyostoma t. tigrinum). Evolutionary Biology , 36: 201-213.