Pictured
above: Adult and juvenile Water Snakes (top left and right). Water
Snake belly pattern (bottom right).
Description: Northern
Water Snakes are medium sized snakes, with adults reaching lengths of 24 to 41
inches (5 to 12 inches in juveniles). They have tan or gray dorsal
surfaces (ie, backs) that are crossed by
reddish-brown, dark gray or black
bands. The lower jaw is usually off-white with darker bands running
vertically,
while their ventral surface (ie belly) is often covered with irregularly placed red blotches
(pictured above). Generally, these patterns are more distinct in juvenile
specimens and tend to fade with age. Furthermore, the reddish bands that
are present in these snakes will often not be obvious in adults (making them
appear to be a drab olive or gray color) unless they are wet. The Northern Water Snake is a member of the family
Colubridae and the sub-family Natricinae, which also includes garter snakes, brown snakes and red-bellied
snakes.
Habitat/Ecology: Water
Snakes are very common near fresh water-bodies (ponds, lakes, rivers, etc.) with rocky
shores and fallen logs that they can hide in and bask on. They are also
common near impoundments and diked rivers or streams. Although they
require much shore debris (ie, fallen trees with tangled root masses, large
piles of rock), they seem to be found infrequently near water-ways in
forests (such as ephemeral wetlands). I have also received reports of
water snakes utilizing musk rat and beaver mounds as basking sites.
As their name suggests, these snakes are very agile swimmers and without
hesitation will drop into the water from a basking spot to avoid danger (I have
even found
them resting completely submerged among the rip-rap that collects along the
Mississippi River, with only their nostrils above the water). Once in the water,
they will either quickly swim
to an adjacent shore to find safety or dive below the surface, only to
reappear again far down stream.
Vogt
(1981) reports that mating occurs in May, immediately following emergence from
hibernation. Like several snake species in the sub-family Natricinae,
water snakes give birth to live young (25 on average) in August/September.
They have been reported to hibernate in muskrat mounds and rocky hills adjacent
to water. I would suspect that they also hibernate in deep burrows or
crevices (that go below the frost line) located along the shores of streams,
rivers, etc., although no reports of this exist in Wisconsin.
These
snakes hunt fish, some invertebrates and amphibians. Water Snakes are said to be preyed upon by
wading birds, such as herons, raccoons and
occasionally large fish.
Remarks: Northern
Water Snakes are common along the Mississippi River and its backwaters (and
throughout the state near water ways). Unfortunately, they are often
believed to be venomous Water Moccasins (which do not exist in Wisconsin outside
of zoological gardens) and dangerous. I have frequently been told stories
by misinformed individuals who swear that they were aggressively chased by a
water moccasin while swimming "up north" during a vacation. Nothing could
be further from the truth for Water Snakes are non-venomous and completely
harmless. Yet, this mistaken identity can result in many water snakes
being wrongfully killed by swimmers, boaters and fisherman. Furthermore,
they are killed by fisherman who believe that they reduce game-fish populations (which is
not true). In fact, it has been suggested that Water Snakes may be
beneficial to fish populations by consuming the sick, dying, or deformed
individuals.
These can be aggressive snakes
if cornered, and
will not hesitate to bite when threatened. However, if left alone, they
pose no threat to humans whatsoever. Furthermore, they will readily dump their
cloacal fluid (or defecate) on the person who has captured them. This is
incredibly unpleasant, and I can safely say (from personal experience) that very few
snakes in Wisconsin have a more
offensive smelling "musk" than the northern water snake.
Water Snakes have
been seen in the La Crosse River Marsh (Myrick Park Marsh), but not as commonly
as Garter Snakes. I have found dead individuals in several areas on the
south side of La Crosse. Most likely, this was the result of
humans. I have also found them in nearby Houston County (Minnesota).
