Thamnophis gigas

Taxobox
name = Giant Garter Snake
status = VU | status_system = IUCN3.1
status_ref = [IUCN2006 |assessors=Hammerson, G.A. |year=2007 |id=21706 |title=Thamnophis gigas |downloaded=2007-10-31]
regnum = Animalia
phylum = Chordata
classis = Reptilia
ordo = Squamata
subordo = Serpentes
familia = Colubridae
genus = "Thamnophis"
species = "T. gigas"
binomial = "Thamnophis gigas"
binomial_authority = Fitch, 1940The Giant Garter Snake ("Thamnoptis gigas") is the largest species of garter snake. It is largely aquatic.

Biology and ecology

The Giant Garter Snake is endemic to the Central Valley wetlands of California. The giant garter snake is active when water temperatures are at twenty degrees Celsius or more, and is dormant underground when their aquatic habitat is below this temperature. Fish and frogs form a large portion of the diet of the Giant Garter Snake.

Conservation biology

Destruction of wetland habitat has been so widespread that this species is listed as threatened by the state and federal governments. [U.S. Fish & Wildlife Service. 1999. Draft Recovery Plan for the Giant Garter Snake. Portland, Oregon.] The giant garter snake populations of the San Joaquin Valley are now tiny disconnected remnants. [U.S. Fish & Wildlife Service. 1993. Endangered and Threatened Wildlife and Plants; Determination of Threatened Status for the Giant Garter Snake. Portland, Oregon.] It has been extirpated from 98% of the former San Joaquin habitat. [ [http://www.californiaherps.com/snakes/pages/t.gigas.html Thamnophis gigas - Giant Gartersnake ] ] The giant garter snake has fared better in the Sacramento Valley because rice cultivation and the associated canals have provided habitat, [U.S. Fish & Wildlife Service. 1999. Draft Recovery Plan for the Giant Garter Snake. Portland, Oregon.] when rice land is fallowed, populations seem to then move away from adjacent ditches. [Wylie, G.D., M.L. Casazza, and L.L. Martin. 2004. Monitoring giant garter snakes in the Natomas Basin: 2003 results. Progress report for The Natomas Basin Conservancy. USGS, BRD Dixon Field Station. 75pp. [Technical Report] [http://www.werc.usgs.gov/dixon/pdfs/Official%20Report%20Natomas%202003.pdf] ]

In addition to habitat loss and fragmentation, introduced predators like the Bullfrog may also be suppressing recovery. [Wylie, G.D., M.L. Casazza, and M. Carpenter. 2003. Diet of bullfrogs in relation to predation on giant garter snakes at Colusa National Wildlife Refuge. California Fish and Game 89(3): 139-145.] Attempts are underway to restore artificial wetlands to provide quality habitat for the giant garter snake, but it is too early to know if these efforts will significantly aid the recovery of this threatened species.

References