Barred tiger salamander

The barred tiger salamander or western tiger salamander (Ambystoma mavortium) is a species of mole salamander found from southwestern Canada in British Columbia, Alberta, Saskatchewan, and Manitoba, south through the western United States to Texas and northern Mexico.[1][2]

Barred tiger salamander
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Amphibia
Order: Urodela
Family: Ambystomatidae
Genus: Ambystoma
Species:
A. mavortium
Binomial name
Ambystoma mavortium
Baird, 1850

Description
Development

The barred tiger salamander typically grows from 15 to 22 cm (5.9 to 8.7 in) but it can grow to 30.5 cm (12.0 in) long at the most and is one of the largest species of salamander in North America. It has a broad head and a sturdy body. The color is variable across its range. The dorsal surface is grey, dark brown or black with bars and spots of muddy yellow giving it a tiger-like coloring. The ventral surface varies from light to dark. Larvae have alternating dark and light blotches on the centre of the dorsal surface and pale stripes running along the sides.[1]

Behavior

Primarily nocturnal, barred tiger salamanders are opportunistic feeders, and will often eat anything they can catch, including various insects, slugs, and earthworms. They are primarily terrestrial as adults, but their juvenile, larval stage is entirely aquatic, having external gills. Breeding takes place during most months of the year. The eggs are laid in water and the developing larvae are exclusively aquatic.

Cannibalism

There are two main feeding morphologies for Barred tiger salamanders known as typical and cannibalistic. The cannibalistic form is characterized by large vomerine teeth as well as slim bodies and wider heads. The development of the teeth allows for the cannibalistic organisms to better hold onto their prey, and the wider heads accommodate for the larger organisms that they prey on.[3]

Another finding was that if the cannibalistic Tiger salamanders live in areas with a fathead minnow population. With their wider heads the salamanders are able to accommodate the large-sized minnows, and the salamanders feed on them. Since the two organisms have similar diets, so eating their competitor has the added benefit of reducing demand on the salamanders' other food sources eaten by both species.[3]

Studies found that cannibalistic Tiger salamanders tend to go through metamorphosis earlier than the typical morphology. Most often, cannibalistic forms are found in drier areas and in shallow waters where competition is much higher, making earlier metamorphosis even more advantageous.[3]

Subspecies

The five recognized subspecies of Ambystoma mavortium are:

  • Gray barred tiger salamander, A. m. diaboli (Dunn, 1940)
  • Barred tiger salamander, A. m. mavortium (Baird, 1850)
  • Blotched tiger salamander, A. m. melanostictum (Baird, 1860)
  • Arizona tiger salamander, A. m. nebulosum (Hallowell, 1853)
  • Sonoran tiger salamander, A. m. stebbinsi (Lowe, 1954)
a.m. diaboli, salamander in residence at Living Prairie Museum, Winnipeg

Distribution and habitat

The barred tiger salamander is found in western Canada and the western half of the United States, but infrequently in California and Nevada. In Canada it is known from British Columbia, Alberta, Saskatchewan and Manitoba. Its range in the United States extends to the southernmost tip of Texas, but no further east than the Dakotas and Oklahoma.[1][2] It has been introduced into southern Arizona because its larvae are used as fish bait.[1]

It is a mainly terrestrial species and is found in lowland deciduous forests, coniferous forests and woodlands. It also inhabits open fields and rough ground, upland meadows, grasslands, semi-deserts and deserts and is occasionally found in streams.[1]

Status

The barred tiger salamander is believed to have suffered some declines in population over several decades. These are likely to have been caused by deforestation and habitat loss. The introduction of non-native predatory fish may be an important cause of declines but this has not been investigated fully.

The Sonoran tiger salamander was classified as an endangered species in 1997, due to the recent increase in human activities causing degradation and fragmentation to their habitat. The species is also threatened by various disease outbreaks carried by species not native to Arizona. The introduction of other species beginning to appear in their habitat can also be predators, such as the crayfish.[1]

In captivity

Tiger salamanders are frequently kept in captivity; they mostly hide and ambush their prey. It is illegal to sell adults in most parts of the United States. Their large size allows for ease of feeding, and their hardy nature makes them excellent captives. Their larval stage is often sold as fishing bait, marketed as "mud puppies" or "water dogs".[4]

Symbol

The tiger salamander is the state amphibian of Kansas. The second grade class of 1993 of O‑K Elementary in Wichita, Kansas, petitioned the governor; students Timothy Boyd and Kristofer Voorhees presented the initial idea for a state amphibian to their teacher.[5] It is also the state amphibian of Colorado after being recognized by the Colorado legislature on March 16, 2012.[6]

References

  1. Petirs, Brian (2002-01-08). "Ambystoma mavortium". AmphibiaWeb. Retrieved 2013-12-05.
  2. Johnson, Jarrett R.; Thomson, Robert C.; Micheletti, Steven J.; Shaffer, H. Bradley (2011). "The origin of Tiger salamander (Ambystoma tigrinum) populations in California, Oregon, and Nevada: Introductions or relicts?". Conservation Genetics. Netherlands: Springer. 12 (2): 355–370. doi:10.1007/s10592-010-0144-2.
  3. McLean, Kyle I.; Stockwell, Craig A.; Mushet, David M. (2016). "Cannibalistic-morph tiger salamanders in unexpected ecological contexts". The American Midland Naturalist. 175: 64–72. doi:10.1674/amid-175-01-64-72.1 – via researchgate.net.
  4. Amorozov. Barred tiger salamander in captivity (photo). Retrieved 1 October 2016.{{cite AV media}}: CS1 maint: url-status (link)
  5. "Barred Tiger salamander". Kansaspedia. Kansas Historical Society. July 2011.
  6. "State amphibian". Colorado State Archives. Retrieved 2019-12-04.

Unused sources
  • Eden, Christopher J.; et al. (2007). "Accuracy assessment of skeletochronology in the Arizona tiger salamander (Ambystoma tigrinum nebulosum)". Copeia. Lawrence, KS: The American Society of Ichthyologists and Herpetologists. 2007 (2): 471–477. doi:10.1643/0045-8511(2007)7[471:AAOSIT]2.0.CO;2.
  • Collins, James P. (1981). "Distribution, habitats, and life history variation in the Tiger salamander, Ambystoma tigrinum, in east-central and southeast Arizona". Copeia. Lawrence, KS: American Society of Ichthyologists and Herpetologists. 1981 (3): 666–675. doi:10.2307/1444572.
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