Reptiles

Amphibians

Plain-bellied Watersnake (Nerodia erythrogaster ssp.)

Description

The general coloration of the Plain-bellied Watersnake can be brown, green, or gray. In Arkansas, the belly color is a plain yellow or cream. Like other nonvenomous watersnakes, it has several dark, vertical lines that outline the upper lip scales. The scales are strongly keeled and the anal plate is divided.

Two subspecies, the Yellow-bellied Watersnake (N. e. flavigaster) and Blotched Watersnake (N. e. transversa), occur in the state. Adults of the Yellow-bellied subspecies usually have a plain-colored back, whereas adults of the Blotched subspecies usually retain more of a juvenile patterning into adulthood. Patterned adults have a series of faint, light colored crossbars bordered in black that run along the backbone. The intergrade zone between these two subspecies in Arkansas is not clearly established.

Juveniles of this species closely resemble that of the Midland Watersnake. A subtle difference can be seen in the patterning near the neck. In juveniles of the Plain-bellied Watersnake, the neck blotches are broken to create a checkered pattern. In the Midland Watersnake, the neck blotches form complete bands. Identification can be confirmed by examining the belly, which is plain in the Plain-bellied Watersnake.

All of the species of watersnakes that occur in Arkansas look similar and it does take some practice to tell them apart (even from the venomous Cottonmouth!). Refer to each species account to learn the subtle differences.


Habitats

This species can be found living concurrently with other species of watersnakes in and around lakes, ponds, streams, rivers, and drainage ditches. It seems to be more at home in still waters. Due to its behavior, it prefers trees along the edges of waters.


Habits and Life History

This species can be observed during daylight hours basking along the banks of water. It is known to bask in branches and vines overhanging the water. (Cottonmouth are not known to exhibit this same tree-basking behavior.) It will quickly drop into the water if threatened; sometimes finding itself in a fisherman's boat! Although this species may occasionally forage during the day, it is usually more active at night. The seasonal activity of this species correlates with the temperature of water and, to a lesser extent, ambient temperature. When the water and ambient temperatures reach their highs in late summer, this is also when you can expect the most activity from watersnakes. It is not uncommon to find this species crossing roads after rainfall.

This species breeds in early spring. In late summer or early fall, females will give birth to live young.


Prey and Hunting Techniques

This species preys primarily upon frogs. Small fish make up most of the remaining portion of the diet.

This species relies upon its stealth and ability to remain submerged for long periods of time to catch its prey. It will actively search through underwater rock crevices and vegetation for its prey, lunging after what it can grasp. A successful bite usually hooks the fin of a fish or foot of a frog. Larger prey is dragged out of the water and eaten on the bank. If, after the prey has stopped struggling, the snake decides to seek out the head--it goes down easier!--a carefully timed flop or jump can leave the snake without a meal. This species has been observed hanging from a tree with its head in the water and catching fish that would swim by.


Temperament and Defense

When first approached, this species will try to flee with great haste. It may dive under the water, hide under a rock, or dart into a hole near the water's edge. It will go to great lengths to avoid conflict with humans.

If it is unable to escape, it will defend itself by flattening its head, hissing, biting, releasing a foul-smelling musk. I find the musk of watersnakes more "foul" than most other snakes. Due to its aggressive defensive behavior, it is commonly mistaken for the venomous Cottonmouth.


Conservation

Many people mistake this species for a Cottonmouth and kill it on sight. This is especially true at rural farm ponds and fish farms where people "protect" their fish stock. Despite persecution, populations of this species appear secure.


State Distribution and Abundance

This species is found statewide, except for a small area in extreme Northcentral Arkansas. Further survey work will likely turn up specimens in this area as well. The Blotched subspecies (N. e. transversa) is thought to occur only in the extreme northwestern portion of the state. This species is abundant in its range. In some areas, it may be the most commonly encountered watersnake species, but is usually second only to the Midland Watersnake.

Gallery

Blotched Water Snake (Nerodia erythrogaster transversa) Plain-bellied Watersnake Plain-bellied Watersnake Plain-bellied Watersnake (Juvenile) Plain-bellied Watersnake (Juvenile) Plain-bellied Watersnake (Juvenile) Plain-bellied Watersnake (Juvenile) Snake - Arkansas (3) Snake - Arkansas (2) Plain-bellied Watersnake (Juvenile) Nerodia erythrogaster (Plain-bellied Watersnake) - juvenile Plain-bellied Watersnake Plain-bellied Watersnake Nerodia erythrogaster flavigaster. Nerodia erythrogaster flavigaster head. Plain-bellied Watersnake Yellowbelly Water Snake (Nerodia erythrogaster flavigaster) Plain-bellied Watersnake Plain-bellied Watersnake Plain-bellied Watersnake Plain-bellied Watersnake 2009 AHS Fall Field Trip 2009 AHS Fall Field Trip 2009 AHS Fall Field Trip Juvenile Plainbelly Watersnake Western Cottonmouth (left), Midland Water Snake (top), and Plainbelly Watersnake (right) Western Cottonmouth (left) and Plainbelly Watersnake (right) 2009 AHS Spring Field Trip 2009 AHS Spring Field Trip 2008 AHS Spring Field Trip - Young Yellowbelly Water Snake 2008 AHS Spring Field Trip - Young Yellowbelly Water Snake Yellowbelly Water Snake Yellowbelly Water Snake Yellowbelly Water Snake Yellowbelly Water Snake Yellowbelly Water Snake Yellowbelly Water Snake Yellowbelly Water Snake Yellowbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake AHS 2006 Spring Field Trip / Plainbelly Water Snake AHS 2006 Spring Field Trip / Plainbelly Water Snake AHS 2006 Spring Field Trip / Plainbelly Water Snake AHS 2006 Spring Field Trip / Plainbelly Water Snake Young Plainbelly Water Snake Young Plainbelly Water Snake Lisman_051005_10011 Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Plainbelly Water Snake Young Plainbelly Water Snake Young Plainbelly Water Snake

Plain-bellied Watersnake x Northern Diamond-backed Watersnake

Belly of a Hybrid Nerodia Hybrid Nerodia Head of a Hybrid Nerodia Hybrid Nerodia Hybrid Nerodia

Contributors

  • Tyler Olcott (Original Contributor)
  • kaptainkory March 22, 2006, at 02:25 PM

Bibliography

  • Behler, J. L., and F. W. King. 1979 (1987). The Audubon Society Field Guide to North American Reptiles and Amphibians. 3rd ed. Alfred A. Knopf, New York. 743 pp.
  • Conant, R., and J. T. Collins. 1998. A Field Guide to Reptiles and Amphibians of Eastern and Central North America. 3rd ed., Expanded. Houghton Mifflin Co., Boston. 616 pp.
  • Irwin, K. J. 2004. Arkansas Snake Guide. Arkansas Game and Fish Commission Pocket Guide. 50 pp.
  • Trauth, S. E., H. W. Robison, and M. V. Plummer. 2004. Amphibians and Reptiles of Arkansas. University of Arkansas Press, Fayetteville. 421 pp.

Discussion

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Page last modified on January 21, 2012, at 08:58 PM