These salamanders locate prey by smell and sight. Their vision is probably best for detecting motion in low light. Sense of smell is important in orienting spotted salamanders to their burrows and to their home pond, as are visual and tactile information. It is believed that home pond odors are preferred compared with foreign pond odors.
During courtship, males nudge and rub females, probably communicating with both touch and smell. Females are attracted by the chemical scents given off by males in the water.
Communication Channels: visual ; tactile ; acoustic ; chemical
Other Communication Modes: pheromones
Perception Channels: visual ; tactile ; acoustic ; chemical
The spotted salamander is still a fairly common species, but its populations are particular vulnerable because of their dependence on vernal pools for breeding. Acidic precipitation has a negative effect upon their embryos, and habitat destruction is a problem, especially as it isolates populations from each other. The species is rated "of Least Concern" by the IUCN, and is not listed by the U.S. Endangered Species Act, in the CITES appendices, or by the State of Michigan.
The spotted salamander is still a fairly common species, and it is not considered endangered. However, the species depends on vernal pools to survive and reproduce, and this habitat is threatened by acid rain and deforestation. The species is rated "of Least Concern" by the IUCN, and is not listed by the U.S. Endangered Species Act, in the CITES appendices, or by the State of Michigan.
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
Spotted salamanders go through several stages over their lifetime. Female salamanders lay their eggs under water, and the larvae that hatch from the eggs are aquatic, with gills for taking oxygen from the water, weak legs and a broad tail for swimming. Larvae feed and grow in the water, and then metamorphose into an juvenile form with lungs and strong legs. Juveniles live on land, and after 2-3 years they mature into adults that can reproduce.
This species has relatively long incubation time in comparison to other salamanders. It takes 4-7 weeks for the eggs to hatch, depending both the temperature of the water they are in, and whether the eggs are laid in shady or sunny areas.
Spotted salamander larvae are 12-13 mm long when they hatch, with feathery gills and only their front legs present
Larvae grow quickly and transform within 2 to 4 months after hatching. Average size after metamorphosis ranges between 27 and 60 mm, depending on the conditions in the pond. The yellow and orange spots are usually acquired within a week following transformation.
Development - Life Cycle: metamorphosis
There are no known adverse effects of Ambystoma maculatum on humans.
Spotted salamanders may help control insect pest species, including mosquitoes that breed in their ponds.
Spotted salamanders can be important to the community of species that live and breed in vernal pools, affecting the abundance and diversity of other species in the pools, especially other amphibians. Gray treefrogs (Hyla chrysoscelis and Hyla versicolor) avoid breeding in ponds with spotted salamanders in them, and depending on the timing and size of the other species present, spotted salamanders may reduce the population of other Ambystoma species in their pools.
Mutualist Species:
Salamander larvae are aggressive predators. They are generalists, eating whatever small animals they can catch. When they first hatch they feed mainly on small insects, and branchiopod crustaceans like Daphnia and fairy shrimp. As they get larger they take larger prey, including isopods, amphipods, larger insects, frog tadpoles, and other salamander larvae. In times of overcrowding, usually when the vernal pools start to dry up, spotted salamander larvae may become cannibalistic and attack members of their own species.
The adult spotted salamander uses its sticky tongue to catch food. Their diet consists mainly of forest floor invertebrates, including earthworms, snails and slugs, millipedes, centipedes, spiders, and a wide variety of insects. They sometimes also eat smaller salamanders, such as the red-backed salamander, Plethodon cinereus.
Animal Foods: amphibians; insects; terrestrial non-insect arthropods; mollusks; terrestrial worms; aquatic or marine worms; aquatic crustaceans; zooplankton
Primary Diet: carnivore (Insectivore , Eats non-insect arthropods); planktivore
Spotted salamanders are found in eastern North America. Their range extends from Nova Scotia and the Gaspé Peninsula west to the northern shore of Lake Superior, and south to southern Georgia and eastern Texas. The spotted salamander is absent from most of southern New Jersey, the Prairie Peninsula in Illinois, eastern North Carolina, and the Delmarva Peninsula.
Biogeographic Regions: nearctic (Native )
Adult spotted salamanders are most abundant in deciduous bottomland forests along rivers, but can be found in upland mixed or coniferous forests if the climate is sufficiently damp and there are ponds suitable for breeding. Adults are rarely seen because they spend most of their time hiding in leaf litter, under fallen wood, or in tunnels below ground.
Like most Ambystoma salamanders, spotted salamanders lay their eggs in fresh water, but only in ponds and pools that lack fish. They often use temporary vernal pools.
Habitat Regions: temperate ; terrestrial ; freshwater
Terrestrial Biomes: forest
Aquatic Biomes: lakes and ponds; temporary pools
Most spotted salamanders (more than 90%) die before they transform and leave their pond, either because their pond dries up, or they are killed by predators or disease. If they do survive and make it out of the pond, they typically live about 20 years in the wild, though some have been reported as old as 30. Their chance of survival from one year to the next is much much higher after they transform.
Range lifespan
Status: wild: 30 (high) years.
Typical lifespan
Status: wild: 20 (high) years.
Average lifespan
Status: captivity: 25.0 years.
Adult spotted salamanders are 15-25 cm in total length, and females tend to be larger than males. Compared to other salamanders, the body is stout with a broadly rounded snout. The sides of the head are often swollen at the back of the jaw. The legs are large and strong with four to five toes.
The background color of metamorphosed spotted salamanders can be black, dark brown, or dark grey, while the bottom half and under-surface of the limbs are a pale slate gray. On either side of the mid-dorsal line of the body are large, round, yellow or orange spots. The spots may vary in number from 24 to 45, and they are arranged in two irregular rows running along the sides from the head to the tail. Unspotted individuals do occur but are rare.
Spotted salamanders have poison glands in their skin, mostly on their backs and tails. These glands release a sticky white toxic liquid when the animal is threatened.
When they hatch, the larvae of this species are 12-17 mm long. Their dorsal surface is dull olive green, and they remain a dull greenish color until they transform into the adult form. The underside of larvae is nearly white, and tail is finely stippled or mottled, with dark pigment near the tip.
Range length: 150 to 250 mm.
Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry ; poisonous
Average mass: 12.84 g.
Average basal metabolic rate: 0.005 W.
Spotted salamander defense begins immediately following laying of eggs. The eggs are laid in masses that are covered in a thick, firm, jelly, overcoat to protect against some predators (e.g. leeches and sunfish) and from dehydration, should the egg mass be temporarily exposed by sinking water levels. There is a particular species of unicellular green alga (Oophila ambystomatis) that grows on and in the jelly. The algae provides extra oxygen to the developing embryos, and may help camouflage the egg mass as well.
Despite this protection, a number of predators eat spotted salamander eggs: adult newts, wood frog tadpoles, crayfish and some species of caddisfly (especially Ptilostomis postica and Banksiola dossuaria) and midges in the genus (Parachironomus). These predators are so effective that in some years up to 90% of eggs may be killed before they hatch.
Spotted salamander larvae are also heavily preyed upon. Hatchlings are eaten by those aquatic creatures previously mentioned and also various aquatic insects, fish, wading birds, other Ambystoma species, and snakes. Hatchlings raised in laboratories often die from protozoan infections as well.
Adult spotted salamanders are preyed upon by larger animals, including skunks, raccoons, turtles, and snakes, especially garter snakes (genus Thamnophis). Like many other salamanders, adult spotted salamanders secrete a milky toxin from glands on the back and tail for defense against predation. The bright spotting on these salamanders functions as a warning to predators of their toxic defense.
Adult spotted salamanders respond to attack by arching the body and sometimes butting with the head or lashing with the tail, probably to expose the predator to as much poison as possible. They sometimes bite, and individuals of all sizes may also make sounds when attacked.
Known Predators:
Anti-predator Adaptations: aposematic
Spotted salamanders begin migration to breeding ponds at night, during the first rain following the thaw of snow. Males respond more quickly to the rain and move faster than do the females, therefore they arrive to the pool first. They also stay longer in the ponds than females do, probably to increase their chances of fertilizing more eggs each year. The number of males present in the breeding pools is greater than the number of females, so when the females arrive the males swim about vigorously, rubbing and nosing each other. Males produced blobs of sperm called spermatophores (up to 80 per male), and the females take these spermatophores into their bodies to fertilize their eggs. Each male may fertilize several females, and each female may take up spermatophores from several males.
Male spotted salamanders may compete with other males for the chance to fertilize females. They push other males away from females, produce as many spermatophores as they can, and sometimes cover other males' spermatophores with their own.
Mating System: polygynandrous (promiscuous)
It takes several years for spotted salamanders to become reproductively mature, and the time required is strongly affected by the climate where they live. In the warmer parts of their range they may be ready to breed in 2-3 years, but further north they males may take 5 or 6 years and females as many as seven years.
See the Behavior section for more details on breeding behavior.
Females lay compact egg masses that are attached to submerged objects. The egg mass is covered with thick, clear or milky-white jelly. Each female lays approximately 100-300 or more eggs per year, in several separate masses. Reported averages are about 200 eggs per female per year.
Breeding interval: Spotted salamanders breed once yearly
Breeding season: Eggs are laid in winter or early spring, starting in late December in the southern portion of the species' range, and as late as early May in Nova Scotia
Range number of offspring: 100 to 370.
Average number of offspring: 200.
Range time to hatching: 4 to 7 weeks.
Range age at sexual or reproductive maturity (female): 2 to 7 years.
Range age at sexual or reproductive maturity (male): 2 to 6 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous
Male spotted salamanders provide no parental care. Females invest nutrients in provisioning their eggs with yolk and supplying them with protective layer of jelly. They also make an effort to lay the eggs in a suitable location, usually on submerged tree branches or aquatic plants. There is no further investment after the eggs are laid.
Parental Investment: pre-fertilization (Provisioning)
