The tiger salamander is a species of mole salamander.  Another name for this  salamander is the eastern tiger salamander.

Description
Eastern tiger salamanders are big, with a normal length of 6–8 inches (15–20 cm). They can grow up to 14 inches (36 cm) in length. Grown-ups are usually spotted with grey, green, or black, and have large eyes. They have short mouths, big necks, strong legs, and long tails. They eat small insects and worms.  Sometimes, grown ups eat small frogs and baby mice

Adults are almost never seen in open fields and often live in holes that are usually 2 feet from the top. Tiger salamanders almost always stay on land as adults, and usually only return to the water to lay eggs. But also they live in both land and water. They also like to swim, even if they are on land. They also are good swimmers. Like all ambystomatids, they are extremely loyal to their birthplace, and will travel long distances to go back. However, a single tiger salamander has only a 50% chance of laying eggs more than once in its lifetime. Males bump a female to initiate mating, and then deposit a spermatophore on the lake bottom. The female picks up the packet and deposits the now-fertilized eggs on vegetation. Large-scale captive breeding of Tiger salamanders has not been accomplished, for unknown reasons.

The larvae are entirely aquatic, with large gills on the outside and a big tail fin that begins just behind the head.  Arms are grown within a short time of coming out of their egg. Some larvae metamorphose quickly. These are known as 'small morph adults'. Other larvae, especially in ancestral pools and warmer climates, may not metamorphose until fully adult size. These large larvae are usually known as waterdogs, and are used many times in the fishing bait and pet trade. Some populations may not metamorphose at all, and become sexually mature while in their larval form. These are the neotenes, and are particularly common where terrestrial conditions are bad.

Conservation status 
While remaining common in many places, tiger salamander numbers have gone down compared with old levels. One of the threats to them is wetland (habitat) destruction. Since they tend to breed in semipermanent wetlands, baby tiger salamanders often experience mass deaths in association with pond drying.

Related species
The California tiger salamander (Ambystoma californiense), the barred tiger salamander (Ambystoma mavortium), and the plateau tiger salamander (Ambystoma velasci), were all once subspecies of A. tigrinum, but are now separate species. Genetic studies made it right to break up the first A. tigrinum population, even though there is some hybridization between the groups.

The Axolotl is also a relative of the tiger salamander.

Sources 
 Hammerson et al. (2004). Ambystoma tigrinum. 2006. IUCN Red List of Threatened Species. IUCN 2006. www.iucnredlist.org. Retrieved on 12 May 2006. Database entry includes a range map and justification for why this species is of least concern.
 LeClere, 2006 Iowa Herpetology Species account, photo and range map of the Tiger Salamander in Iowa

Other websites
National Geographic Page
California Tiger Salamander

References

Salamanders