Long-toed Salamander. Ambystoma macrodactylum

Description: Adult: Total length 80-120 mm (snout-vent length about 37-58 mm). A relatively slender salamander with an oval head, blunt snout and rather large eyes with the iris tinged with bronze. Normally twelve costal grooves on each side of the body. Limbs slender, toes narrow, elongate and unwebbed. Tail long, cylindrical in section at the base, but becoming compressed distally. Background colour dark greenish-grey to black, with a narrow yellow dorsal stripe running from snout to tail tip. Large yellow patches on eyelids and white flecks on the flanks. Belly greyish.

Larvae: Total length up to 70 mm. Grey or light brown with irregular darker flecks and a silvery belly. Fewer than fourteen gill rakers on the anterior surface of the third gill arch. Balancers (lateral out-growths below each eye) present.

Variation: Postmetamorphic juveniles typically more brightly patterned than adults, often with fewer light flecks or speckles on the flanks and dorsum. Males with proportionately longer limbs and tails than females. In breeding season the cloacal region is swollen in males. Cloaca longer in males than females. Vent of males lined with papillae.

Natural history: In Alberta, active from early spring to early fall, although, in the United States, it may be active throughout the winter, especially during rainy periods. Most conspicuous in Alberta in April and May when the adults migrate to the breeding sites (typically in periods of high humidity), and in September when the juveniles leave for hibernation sites. Adults usually remain at the breeding pond for only about one month or less. Typically found under rocks, rotting logs and other debris near ponds, lakes or occasionally streams.

Population sizes can be very large, numbering in the thousands. Feeds on small invertebrates, chiefly arthropods. Rarely seen in the open, except during the breeding season. Adults on average live six to seven years, with a maximum of ten having been recorded, and are almost exclusively nocturnal. Birds and shrews are the most frequent terrestrial predators. Larvae feed primarily on zooplankton and select prey items in proportion to their own body size. Natural predators include garter snakes.

Reproduction: Mating occurs in early spring, often before breeding ponds are clear of ice. Generally prefers shallow areas of permanent ponds. Males hold females in pectoral amplexus and rub their mental (chin) glands across the female's snout. After terminating amplexus the male swims ahead of the female and deposits a spermatophore (packet of sperm) on the substrate. The female picks this up with her cloaca, and lays eggs soon after. Eggs laid singly or in clumps, on vegetation or twigs. Eggs hatch after approximately three weeks, but the time for hatching varies considerably with water temperature. In Alberta, larvae sometimes overwinter before metamorphosing. Sexual maturity is attained in the second or third year.

Distribution: In Alberta, occurs at elevations of 1,075-2,800 m in sub-alpine to alpine areas, from the Montana border north through Jasper National Park (except for the Icefields region). A recent range extension record reports this species from aspen parkland near Fairview. Most often encountered in valley bottoms with fluvial or glaciofluvial unconsolidated substrates, and high groundwater probability. Range in Alberta probably continuous to about 54°30' N. Northern populations occur as low as 549 m. Elsewhere, it occurs from southeastern Alaska to northeastern California, including Vancouver Island, east to the eastern foothills of the Rockies in Idaho, Montana and Alberta. Isolated populations exist in Santa Cruz and Monterrey counties, California.

Conservation status: Previously considered rare, this taxon has been the subject of extensive field monitoring programs. These have revealed that it is much more common than previously believed, but that its distribution is patchy. Currently not thought to be in decline.

Remarks: Five subspecies are recognized. Ambystoma macrodactylum krausei is the Alberta form, occurring from the eastern Kootenays in east central British Columbia, south through the Rockies and their foothills into western Montana and east central Idaho.

Significant references: Anderson 1961, 1967; 1968a, b; Beneski et al. 1986; Ferguson 1961, 1963; Fukumoto 1995; Graham 1997; Graham and Powell 1999; Hamilton et al. 1996; Howard and Wallace 1985; Kleinschroth, 1985; Knudsen 1960; Mittleman 1948, 1949; Nelson et al. 1995; Oseen et al. 1995a, b; Nussbaum 1985; Petranka 1998; Powell and Russell 1996a; Powell, Nelson and Russell 1993; Powell et al. 1997b, c; Russell et al. 1996; Rodgers aTnd Jellison 1942; Salt 1979; Shepard, 1977; Slater 1936; Tyler 1996; Walsh 1998.