Ambystoma maculatum

Spotted salamanders have smooth skin with vertical grooves on each side of the torso, a broad head, and small eyes. The upper side is black with numerous rounded yellow or orange spots. The belly is slate gray. Maximum total length is about 9.8 inches (25 cm). Large larvae have large external gills, a reticulated pattern on the upper surface, small dark spots on the lower sides, and a pale belly; they lack dark stippling on the throat. Egg masses are up to several inches in diameter, have clear to milky or green jelly, and contain usually several dozen eggs.

Spotted salamanders inhabit hardwood and mixed forests, in the vicinity of swamps and vernal pools. They are usually underground or under soil surface objects except during the breeding period. Logs, stumps, and mammal burrows provide important cover (Faccio 2003). In New York, distribution apparently is influenced by soil pH (Wyman 1988).

Eggs usually are attached to submerged stems or other objects in vernal pools and semipermanent or permanent ponds in or adjacent to forest. In many areas, the species breeds mainly in ponds inaccessible to predatory fishes; however on the Atlantic Coastal Plain of the southeastern United States, spotted salamanders breed in sloughs or backwater lowland areas along streams that frequently contain or are easily colonized by predatory fishes that opportunistically feed on amphibian larvae (Semlitsch 1988). Eggs may be laid in ponds when they are ice-covered if salamanders already are present in the pond (States et al. 1988).

Larvae may be preyed on by larval A. opacum where the two occur together. Predation on larvae by fishes may prohibit successful reproduction (Ireland 1989). In a Massachusetts pond, survival to metamorphosis was 3.1% for 10,000+ embryos in a year when pond did not dry; up to 13% survival recorded in other studies (see States et al. 1988). In West Virginia, larvae of the caddisfly Banksiola dossuaria preyed on embryos (Stout et al. 1992). In Pennsylvania, larvae of the caddisfly Ptilostomis postica sometimes preyed heavily on embryos (Rowe et al. 1994).

See Semlitsch (1988) for information on factors affecting ecological distribution in southeastern U.S.

The egg masses of spotted salamanders sometimes contain green algae that use the carbon dioxide produced by the embryos and in turn produce oxygen that the salamander embryos can use.

Rain and warming temperatures stimulate migrations to breeding ponds in winter or early spring (Grace and Church 2003). Migrations to breeding sites occur in March-April in the northern part of the range, mainly December-February in the south. In eastern Missouri, migration to ponds occurred after the first week of February on all days when mean 3-day temperature was at least 5.5 C and precipitation at least 4 mm (Sexton et al. 1990). After arriving in the breeding pools, females pick up sperm from the spermatophores that males deposit on the pool bottom. Soon thereafter females attach masses of eggs to submerged stems or other submerged objects. Individual females deposit up to 250 eggs (average <100); eggs of an individual females may be laid in one large mass or divided among several masses of about 50-90 eggs. Hundreds of females may deposit eggs in a single pool, and the egg masses of different females often exhibit an aggregated dispersion pattern. Larvae hatch in 1-2 months.In a pond in Ohio, hatching rate over 4 years was 60-72%, and the number of larvae that hatched ranged from 232,000 to 527,000 (Brodman, 1995, J. Herpetol. 29:111-113). Larvae metamorphose in 2-4 months or sometimes overwinter in the pond. In eastern Missouri, metamorphosis occurred mainly by October in some years, in spring after overwintering in other years (Phillips 1992). In Massachusetts, mean time from hatching to exit from pond was 98 days (States et al. 1988). Newly metamorphosed individuals live on land for a few years before returning to water to breed (usually in their natal pool).

In Quebec, most individuals caught in temporary ponds in spring were between 2 and 18 years old; most females were mature by the age 7 years at SVL greater than 78 mm whereas many males reached maturity between the ages of 2 and 6 years at SVL greater than 63 mm (Flageole and Leclair 1992).

Many individuals usually breed in a single pool (e.g., in eastern Massachusetts, 196 males and 132 females entered a pond with a surface area of about 30 square meters; 118 egg masses were found (States et al. 1988). Harris (Copeia 1980:719-722) found 237 egg masses in one pond.