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Canadian Herpetological Society

Société d'herpétologie du Canada

Ambystoma jeffersonianum
Jefferson Salamander / Salamandre de Jefferson

Jefferson Salamander
Photo is of a Blue-Spotted Salamander, but the two species cannot be reliably distinguished in the field.

This salamander and the Blue-Spotted Salamander are part of one of the most bizzare and complex mysteries of amphibian biology. These two species are associated with hybrids, usually female, with three sets of chromosomes (triploid) rather than the regular two (diploid). Under certain circumstances, when hybrid females breed with male Blue-Spotted or Jefferson Salamanders, sperm stimulates egg development but is not incorporated into the genetic material of the egg. In such cases, the offspring is genetically identical to the mother. Sometimes the sperm is incorporated into the egg, producing offpsring with four sets of chromosomes (tetraploids). All these diploid, triploid and tetraploid salamanders look quite similar. Biologists are still trying to understand this complicated system.

The Jefferson Salamander is dark brown to brownish gray with bluish flecks and grows to over 20 cm in total length. The Blue-spotted Salamander is bluish black with large blue flecks and grows to only about 12 cm total length. For both species the tail makes up about half of the total length.

Confusing Species
The bluish colour of these species is very diagnostic. No other salamanders in eastern Canada can be easily confused with the Jefferson complex.

The Jefferson Salamander is limited to southern Ontario, while the Blue-Spotted Salamander is more widespread, from southern Manitoba to Nova Scotia and Labrador. Outside of Canada, they are found only as far south as Virginia.

These salamanders are found in a wide variety of woodland habitats: deciduous, coniferous or mixed forests, as well as swamps. Breeding ponds can be permanent swamps or temporary ponds, marshes or even roadside ditches.

Breeding occurs in the spring. Adults make their way to breeding ponds on warm rainy nights. Females can lay up to 200 eggs either singly or in loose groups. The eggs hatch in about a month's time and the larvae transform into salamanders in late summer.

Natural History
Outside of the breeding season, adults are completely terrestrial, often living underground in burrows. Salamanders are carnivores eating a large variety of insects and other invertebrates such as spiders and worms.

Conservation Concerns
The loss of wetlands and the destruction of forests threaten many salamanders. Many salamanders are also killed on our roads every spring during their migration to the breeding ponds. It has been designated Threatened by COSEWIC.