|
Spotted
Salamander
Ambystoma
maculatum
Pine
County, MN
Pine
County, MN
Pine
County., MN
Pine
Co., MN
Status
The spotted salamander was first documented in Minnesota
in May 2001. (C. Hall personal communication). We have
yet to determine their range and abundance in Minnesota. Spotted
salamanders will have no official status in Minnesota until
we know more information. If you find a salamander fitting
the spotted salamander description below, please contact us
or the DNR!
Description
This is a rather large salamander reaching lengths of 6 to
7 3/4 inches long (Conant and Collins, 1991). Adults have
a black, bluish black, or gray ground color with two rows
of round yellow or orange spots running lengthwise down the
back. The rows of spots may be irregular or straight. The
spots run from the eyes to the tail tip and are usually well
rounded and do not run together to form large blotches or
lines. Some individuals have two bright orange spots on the
head that stand out against the bright yellow spots on the
body and tail. The belly and lower sides are slate gray and
lighter than the dorsal ground color.
Often
there are silver fleckings present on the sides. In adults,
the bottom lip and throat are light gray. They have 11 to
13 costal grooves and there are four toes on the front feet
and five toes on the back feet. Larvae are olive green above,
lighter colored below, and have no strong markings except
near the tail tip. They also have bushy gills. Newly tranformed
spotted salamanders have light bellies and smaller dorsal
spots (Petranka 1998).
Spotted
salamanders look very similar to tiger salamanders. They may
be distinguished from one another by the following: spotted
salamanders have 1) rounded bright yellow spots arranged in
two irregular rows down back and tail and (in some) a pair
of orange spots on the head, 2) light gray sides and belly
with silver flecks, 3) in adults, lower lip and throat are
light gray. Tiger salamanders have 1) large yellow or olive
blotches that are scattered or often connect forming a network
and no orange spots at all, 2) belly is olive or blackish
and yellow from sides extends onto belly, but no silver flecks,
3) in adults, lower lip is usually bright yellow and throat
is yellowish olive.
Subspecies
There are no recognized subspecies of the spotted salamander,
Ambystoma maculatum.
Range
Known only from Pine County in Minnesota at this time. Spotted
salamanders have a large national range in states east of
Minnesota.
Habitat
Spotted salamanders require woodlands with ponds for breeding.
Petranka (1998) states that mature deciduous forest is the
main habitat type for the spotted salamander, but Minton (1972)
also makes note of mixed hardwood habitats. Vernal pools are
very important for breeding. Fish free ponds are best, but
Figiel and Semlitsch (1990) found that larvae may change habitat
usage to survive in ponds containing fish.
Habits
Spotted salamanders are obviously one of the most secretive
salamanders in our state, which is why they have gone undetected
for so long. Nearly all of their time is spent underground
in burrows of other animals. Occasionally, they are found
above ground on damp or humid nights. The only time they are
found above ground in numbers are during heavy spring and
fall rains while they migrate to and from overwintering sites.
It is not known how visible these migrations are in Minnesota.
Spotted
salamanders breed early in the spring, but slightly later
than some of our first spring amphibian breeders. The adults
migrate to the breeding ponds during periods of heavy snowmelt,
warm spring rains, or humid nights if there is no rain. The
migration appears to be synchronized. Males court the females
by nudging and rubbing them with their snouts. The male drops
a spermatophore, which the female walks over and picks up
with her cloacal lips. Males may drop nearly 100 spermatophores
in a season. The breeding period lasts from a couple nights
to over a week. The time varies by location. The females then
lay from 1 to 200 eggs in a globular mass. The mass is attached
to twigs or other underwater structures; very rarely they
are laid on the bottom. The mass is covered with a jelly-like
coating which may be clear or white. This prevents some predators
from eating the eggs (Petranka 1998), but it is probably not
the full function of the coating. The eggs hatch in only a
few weeks. The larvae actively feed and grow for 2 to 4 months.
The larval stage varies based on geographic location and water
temperature. Some larvae are known to overwinter and transform
the following spring (Phillips 1992).
Spotted
salamanders spend a few years as terrestrial juveniles before
becoming sexually mature. The terrestrial juvenile period
may last from two to five years or longer. Transformed juveniles
and adults spend nearly all of their time underground. They
may be found under rocks, logs, or other debris especially
during wet, damp, or humid conditions.
Food
Spotted salamanders eat invertebrates such as earthworms and
insects or anything else they can catch and swallow. Adults
secrete a milky toxin from glands on the back and tail for
defense against predation.
|
