Eastern Tiger Salamander Ambystoma tigrinum

Adult from Boone County

Identification

This is the largest terrestrial salamander in the state. It is a chunky black to dark brown salamander with an irregular pattern of yellow blotches and a lightly mottled ventral coloration. This species grows to around 7-10 in total length with some individuals reaching lengths of around a foot. Females attach their eggs to sticks and debris near the bottom of the ponds in globular clumps of up to 50 eggs.

Adult from Wayne County
Larvae from Wayne County

The Spotted Salamander (Ambystoma maculatum) is similar in appearance to this species, but generally has smaller spots that are arranged roughly in two rows dorsally, unlike the irregular dorsal blotching of Eastern Tiger Salamanders. In addition, the spots of the Spotted Salamander never extend on to their underbelly where the blotches of the Eastern Tiger Salamander usually do. The head and general body size of a typical Eastern Tiger Salamander is much larger than that of typical Spotted Salamander.

Ecology and Conservation

Eastern Tiger Salamanders are found in a variety of habitats from flooded fields to marshy woodlands, but they seem to avoid hilly terrain. In Indiana they have been found in open grasslands, low marshes, mature well-drained forests, agricultural land, and even in suburban and urban areas where they occasionally turn up in window wells. Eastern Tiger salamanders will utilize temporary pools and marshes as well as permanent ponds for breeding and are tolerant of fish. They will even utilize cattle ponds in agricultural areas. This species presumably feeds largely on terrestrial invertebrates, but has been known to take frogs, snakes, and other small vertebrates in captivity.

Breeding marsh from Wayne County
Permanent pond from Clinton County

This species is able to breed in larger permanent ponds with fish, but will also use small marshes that only retain small amounts of water during the summer. I have rarely heard of them breeding in shallow, ephemeral pools like many other ambystomatids will. After being deposited, the eggs take a little under a month to hatch and the larvae usually transform sometime during June or July, but there is evidence of neoteny (larvae become sexually mature without metamorphosing into the terrestrial form) in this species in parts of Indiana. Eastern Tiger Salamanders are among the first ambystomatids to move during the breedings season. Warm days in January and February will generally spark movements in southern Indiana, while March is the start of the breeding season further to the north. Eggs are usually laid during February or March and they take around a month to hatch (Minton 2001, 48). Adults have usually left the ponds by mid March. The larvae transform sometime during early summer or late spring. Easter Tiger Salamanders occasionally turn up throughout the summer and fall in some areas, but are most often seen reliably during the breeding season. There is often a resurgence of activity during the fall when they can sometimes be seen crossing roads during rains.

Though their occurrence in Indiana is quite patchy and seemingly unpredictable, they are abundant where they occur. They tend to be the dominant salamander species in wetland communities in which they breed and may outcompete other ambystomatids. They tolerate habitat disturbance as well as predatory fish in their ponds. I am unaware of any major threats to this species in Indiana.

Distribution

The tiger salamander species complex is one of the most widespread groups in North America; in the United States, populations reach as far west as Washington, as far south as southern Texas, as far east as the Carolinas, and north through many of the Great Lakes states. Eastern Tiger Salamanders are found throughout Indiana, but are largely absent from the unglaciated hills of south-central Indiana, the Switzerland Hills of southeastern Indiana, and the bottomland forests and swamps of southwestern Indiana.

Taxonomy

What were once recognized as subspecies of the Eastern Tiger Salamander (Ambystoma tigrinum) are now often recognized as distinct species. Under the previous taxonomic arrangement, the Eastern Tiger Salamanders found in Indiana were known as A. t. tigrinum, but they are now often referred to simply as A. tigrinum. The Eastern Tiger Salamander belongs to the family Ambystomatidae, which is represented in Indiana by eight species (plus the unisexual Ambystoma)--the most of any state!

Literature Cited

Brodman, R. 2003. Amphibians and Reptiles from Twenty-three Counties of Indiana. Proceedings of the Indiana Academy of Science 112:43-54.

Conant, R. and J. T . Collins. 1998. Reptiles and Amphibians of Eastern and Central North America. Third Edition, Expanded. Houghton Mifflin, New York, NY.

Kinney, V. C., N. J. Engbrecht, J. L. Heemeyer, and M. J. Lannoo. 2010. New County Records for Amphibians and Reptiles in Southwestern Indiana. Herpetological Review 41:387.

Minton, S. A. Jr. 2001. Amphibians and Reptiles of Indiana. Indiana Academy of Science, Indianapolis, IN.

Petranka, J. W. 1998. Salamanders of the United States and Canada. Smithsonian Institute Press, Washington D.C.

Distribution Map
Distribution map of Eastern Tiger Salamander (Ambystoma tigrinum)
Photographs