Snakes in the Salt Marsh
(are not cottonmouths)
By Frederick Boyce
I missed a good opportunity to educate the other day and hopefully can make
up for it a little by addressing the issue in this months article. I was out in the
Snake Pavilion of the NC Aquarium at Pine Knoll Shores, talking to visitors and
answering questions, a favorite activity that I wish I had time to do a lot more, and
a gentleman asked me if cottonmouths (aka water moccasins), our only aquatic
venomous snakes, were ever found in brackish water. I answered that these tough
and resilient snakes can be tolerant of brackish water and certainly have no problem
with entering or traversing salt marshes or estuaries in search of food, but do
not normally live there or seek out such habitats. He said that he had seen some
snakes swimming in brackish water and mentioned that they appeared darker than
the cottonmouth we have on display. At the time, I thought little of his remark
as cottonmouths often do darken with age, although in our area they tend to be
greenish or greenish-yellow with chestnut brown-and-black bands.
There was, as usual, a large crush of folks looking at the snakes, many of whom
had questions of their own, so I became distracted and didn’t have time to consider
his interesting question further until much later, when I thought about it and
realized that I had completely overlooked one other very interesting possibility.
North'Carolina has two reptiles and one amphibian that ^ve endemic, meaning that
they are found in no other state and, indeed, nowhere else in the world.
The amphibian is an attractive, foot-long aquatic salamander with bushy red
gills called the Neuse River waterdog that is only found in the Neuse River and its
tributaries.
The two reptiles are both snakes—one is the Outer Banks kingsnake, a subspecies
of the familiar black-and-white eastern kingsnake in which the normally solid
black areas between the white bands are broken up by white speckling. As its name
suggests, the Outer Banks kingsnake occurs only on the Outer Banks between Cape
Hatteras and Cape Lookout. These unique snakes are highly prized by fanciers
and are strictly protected in NC as a “species of special concern,” so collecting or
molesting them in the wild is prohibited.
Also protected is our other endemic snake, the Carolina watersnake, Nerodia
sipedon williamengelsi, a subspecies of the common and more widespread northern
watersnake, Nerodia sipedon, which is found across much of the eastern and mid-
United States. The Carolina watersnake is also known as the Carolina salt-marsh
snake, as it does indeed prefer to live in brackish water environments and can be
found in salt marshes and estuaries along the Outer Banks as well as the mainland
shores of the Pamlico and Core sounds from Dare County to Cape Lookout. I
have heard unconfirmed reports of their being seen on Bogue Banks, but have
encountered none here myself, as we are just a little bit south of their established
range. I have found them swimming in the intracoastal waterway in the Adams
Creek area near the Neuse River, and have also found them killed on Merrimon
Road, between the salt marshes near the intersection of Laurel Road and Merrimon
Road. They are certainly found Down East along both sides of Core Sound.
Carolina salt-marsh snakes live on a diet of mostly small fish, such as
mummichogs or sheepshead minnows, and eels. They will also catch frogs on rainy
nights—especially leopard frogs, one of the few amphibians that can tolerate low
levels of salinity for brief periods. In color, the Carolina salt-marsh snake is overall
a very dark snake, having a dark gray background with heavy black bands. They are
much darker than typical northern watersnakes, which are shades of brown and tan,
and can often appear to be entirely black, especially when wet. Their undersides are
shiny black and marked profusely with tiny white half-moon shapes.
I nov\r feel certain that the gentleman I spoke with at the aquarium had actually
been seeing dark Carolina watersnakes and not cottonmouths, and I wish I could
go back now and talk to him again. I would like to know where he had seen them as
TheStioreline I May 2018
their distribution in. the brackish waters of eastern North Carolina is still a point of
great interest to herpetophiles.
Thanks to Dr. Rusty Gaul, who has spent a significant amount of time and effort
studying these interesting watersnakes, for his assistance with this article.
Frederick Boyce is the staff herpetologist at the NC Aquarium at Pine Knoll Shores.
A Carolina watersnake—Photo by Nathan Shepard, wildlife biologist with the NC
Natural Heritage Foundation
for the f
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