Size and Life Span
All adult salamanders found in Canada have 4 legs; 3 species in the southeastern US have front legs only. Hence, salamanders differ from the limbless, tropical caecilians of the amphibian order Gymnophiona. Salamanders have tails, and teeth in both jaws; thus, they differ from the third group of amphibians, the FROGS, which lack tails (as adults) and lower teeth.
Salamanders can sense vibrations but are unable to hear. They are generally voiceless, although some utter faint squeaks. Salamanders have 2 nostrils connected to the mouth, eyes often with movable lids, a mouth with fine teeth, a tongue often protrusible, a skeleton largely bony, a 3-chambered heart with 2 auricles and one ventricle, and body temperature dependent on environment. They breathe by gills, lungs, mouth lining, and skin, sometimes in combination, sometimes separately. Members of the stream, spring, and damp woodland dwelling family (Plethodontidae) lack lungs and breathe through the skin and mouth.
All Canadian species lay eggs, the number laid and incubation period varying with each species. The mudpuppy, which spends its entire life in water, lays its eggs under stones where they are guarded by the female. Adult and larvae red-spotted newts (Notophthalmus viridescens) live in water, but in most parts of their range after the young grow legs they loose their gills, leave the water and spend a year or more on land. At this stage, they are referred to as "efts" At maturity, they return to ponds to breed. In the lungless salamanders, some lay their eggs under stones in water (two lined) or in moist places along brooks (dusky and spring); others lay in sphagnum above woodland pools (four toed), or in damp, rotted logs (redback, wandering and Ensatina). Mole salamanders (family Ambystomatidae) deposit eggs in ponds in a jellylike mass attached to vegetation. Some species go to ponds, ditches and lakes in early spring to lay eggs, while stream and woodland species may not deposit until summer. Water-hatching young breathe through gills and may retain these for several years before transforming into land dwelling adults. In a few species under certain environmental conditions (eg, tiger salamander (Ambystoma tigrinum) and red spotted newt), the larval gills are retained after maturity and these adults remain in the water.
A complication in species recognition where ranges overlap occurs with Ambystoma species: laterale will hybridize with both jeffersonianum and texanum, and the laterale X texanum hybrid in turn interbreeds with tigrinum where it occurs on US islands in Lake Erie, just south of Canada. All crosses produce triploids (ie, containing an extra set of chromosomes), which are most often female and mate with males of either parent species but usually produce solely triploid females like themselves. Some crosses produce diploid (ie, normal number of chromosomes or even tetraploids or pentaploids). The mixing is further complicated by the hybrids having mitochondrial (ie, outside the cell nucleus) contribution from yet another salamander, A. barbouri, which does not occur in Canada and represents a postglacial hybridization before the line spread north.
Salamanders are collected each year by scientific institutions for research and by individuals for terrarium pets. Mudpuppies are taken for use in university and high school biology courses; their capture is regulated provincially. Several species of salamanders are considered at risk because of low numbers and restricted habitats or range, and are protected by law.
Author S.W. GORHAM Rev: FRANCIS R. COOK
F.R. Cook, Introduction to Canadian Amphibians and Reptiles (1984); J.W. Petranka, Salamanders of the United States and Canada (1998); A.V. Robertson, C. Ramsden, J. Niedzwiecki, J. Fu and J.P. Bogart, "An Unexpected Recent Ancestor of Unisexual Ambystoma," Molecular Ecology 15:3351 3351 (2006)
Links to Other Sites
Endangered Species in Endangered Spaces
An informative website about rare and endangered plants and animals in the Thompson-Okanagan region of British Columbia. Click on the menu at the left side of the page for information about specific species. From the Royal British Columbia Musuem.
Canada's Biodiversity: Focus on Amphibians
A very extensive resource about Canadian species of frogs, salamanders, and newts. Provides illustrated notes about their life-histories, habitats and more. From Canada's Digital Collections.
Canadian Biodiversity Website
A great information source for all budding biologists. Learn about biodiversity theory, natural history, and conservation issues. From McGill’s Redpath Museum.
Why survey Herptiles?
This Parks Canada website is devoted to the study of amphibian and reptilian species native to Canada.
Amphibian Specialist Group
The Amphibian Specialist Group focuses on conservation of amphibians and their habitats around the world. Hop over to the link for “Froglog,” a bi-monthly newsletter which offers current information about the decline of amphibian species. Part of the International Union for Conservation of Nature and Natural Resources.
The AmphibiaWeb website provides access to information on amphibian biology and conservation. From the University of California.
Amphibian Species of the World
A detailed, highly technical information source about amphibian species of the world. From the American Museum of Natural History.
Shawnadithit grew anxious waiting for her uncle, Longnon, to return to camp at the junction of Badger Brook and the Exploits River, deep in the wilds of Newfoundland...