the yellow-bellied watersnake (Nerodia erythrogaster), southern or broad-banded watersnake (Nerodia fasciata), diamondback watersnake (Nerodia rhombifer), and the uncommon Mississippi green watersnake (Nerodia cyclopion). Some less common species that are occasionally encountered are the western mud snake (Farancia abacura), prairie kingsnake (Lampropeltis calligaster), speckled kingsnake (Lampropeltis holbrooki), Louisiana milk snake (Lampropeltis triangulum), and Slowinski's cornsnake (Pantherophis slowinskii). The rare and endangered Louisiana pine snake (Pituophis ruthveni) is known form historical records in the Big Thicket but might be extirpated from the area now. The Louisiana pine snake is closely associated with the Baird's pocket gopher (Geomys breviceps), both for prey and its burrows for shelter, and both species occupy longleaf pine uplands, savanna, and sandyland, habitat which is dependent on periodic cycles of wildfires to maintain an open understory. There are five species of venomous snakes in the area. Two rattlesnakes, the pygmy rattlesnake (Sistrurus miliarius) and the canebrake or timber rattlesnake (Crotalus horridus) are both uncommon to rare. Timber rattlesnakes are a threatened species in Texas, as they are in most states where they occur and are protected by state laws. The Texas coral snake (Micrurus tener) is not uncommon however, they are secretive, often fossorial, and seldom seen. Two of the most common snakes, venomous or non-venomous, are the copperhead (Agkistrodon contortrix) and cottonmouth (Agkistrodon piscivorus). Venomous snakes deserve caution and respect, but are safely observed when distances of 15–20 feet are maintained. Amphibians: There are 31 species of amphibians found in the Big Thicket area, including 11 species of salamanders and 20 species of frogs and toads. Some of the more commonly encountered salamanders in the region include the smallmouth salamander (Ambystoma texanum), dwarf salamander (Eurycea quadridigitata), and central newt (Notophthalmus viridescens). The three-toed amphiuma (Amphiuma tridactylum) is one of the larger salamanders in the world and can grow over . Three salamanders, including the three-toed amphiuma (Amphiuma tridactylum), Gulf Coast water dog (Necturus beyeri), and lesser siren (Siren intermedia), retain their gills from the larva stage and live their entire lives in the muddy waters of east Texas and consequently, although not rare, are seldom seen except by an occasional fisherman or those who specifically go look for them. Likewise, mole salamanders (members of the genus Ambystoma), including the spotted salamander (Ambystoma maculatum), marbled salamander (Ambystoma opacum), mole salamander (Ambystoma talpoideum), and tiger salamander (Ambystoma tigrinum) spend much of their lives underground and are infrequently seen except