Thursday, May 24, 2012

Graham's Crayfish Snake

This subtly beautiful snake is the Graham's Crayfish Snake (Regina grahamii). The scientific name of grahamii, is in honor of Lieutenant Colonial James Duncan Graham,United States Topographical Engineer, who collected the type specimen. They are rather drably colored in shades of tan or brown, but there is something about them that is uncommonly beautiful. I found this one at Squaw Creek NWR about a week and a half ago basking on the road near the wetland. It was the first time I've seen this species and I was exceedingly excited to see it and get the chance to photograph it. They are normally a shy, secretive snake that is rarely encountered by humans. They are not prone to bite, but if disturbed they will musk you, which is exactly what this one did, and I didn't mind in the least. It was worth every stinky minute to hold such a rare snake in my hands. After snapping several photos I released it closer to the waters edge and away from the road.

In Missouri this species is found statewide near wetlands, sloughs, oxbow lakes, marshes and ditches that hold water. Although statewide they are uncommon in Missouri. They are specialists in their diet and feed almost exclusively on crayfish (hence the name). They prefer freshly molted crayfish which are much softer and easier to eat. There are reports of this species consuming small frogs and fish, but I believe these are uncommon occurrences.

Locality map for Graham's Crayfish Snake

The above map shows the most recent reported occurrences for the Graham's Crayfish Snakes. Each of those black dots represents an area near a wetland or marsh. 

These snakes are medium sized at around 28-30 inches in length and will be a uniform brown, gray or tan color. Their belly is cream colored with a zig-zag black stripe down both sides. There may or may not be a faint dorsal stripe present. The lateral stripe stands out and will be cream or white in color.

While you may find this species hanging out with watersnakes in the genus Nerodia, they differ from them in many ways. First and foremost their temperament. Graham's tend to be docile by nature and not prone to bite, whereas watersnakes like the Northern Watersnake (Nerodia Sipedon Sipedon) would just as soon bite you as look at you. Nerodias typically get much larger and are more readily seen. Graham's tend to hide under logs, rocks or other debris at the waters edge where they attempt to avoid being seen. During the spring and fall Graham's may be seen basking on the road like this specimen, but during the summer months it is believed they become almost entirely nocturnal.

During the winter they will often hibernate in old crayfish burrows. They will also use crayfish burrows to escape the heat of summer. These snakes are tempting to try and keep as pets as they are extremely docile and pretty, but should not be removed from the wild. They are protected in most of their range, including in Missouri. In addition to being protected they are extremely difficult to keep in captivity because of their diet. They require crayfish that have recently molted and a steady supply of them. They are reported to stress easily and develop skin lesions. These snakes are best enjoyed in their natural habitat by observing and photographing them and considering yourself lucky when you come across one. 

Monday, May 21, 2012

Northern Watersnake

Northern Watersnakes (Nerodia Sipedon Sipedon) are large native watersnakes occurring throughout Missouri.These are the most common of all the species of Nerodia found in Missouri. They are found in numerous habitats, including ponds, lakes, rivers, sloughs, wetlands, marshes and drainage ditches.

This species may be active during the day or at night and are often seen basking on logs or exposed rocks within the water. They will also climb trees overhanging the water and rest. Like most watersnakes they will feed on a wide variety of aquatic prey including fish, tadpoles, crawdads, and frogs. They will also eat birds and small mammals that wonder near the water. They slither around the waters edge hunting for potential food.

(Eating huge catfish)

At the refuge they drained a bunch of the water to create mudflats for the shorebirds. When the water poured out of the drain into the spillway numerous fish were forced out as well. As the water retreated it left behind numerous dead fish. Vultures, snapping turtles, raccoons, possums and other predators took full advantage of the free food. The watersnakes were even attracted to the odors and consumed their fair share of fish, but it would appear this particular snake is sizing up a fish that is way more than he can tackle.

Their color varies specimen to specimen, and will be banded with brown, reddish or brown-black. They may darken with age and become nearly black. When wet their pattern is much more obvious and they are actually a beautifully marked snake. They typically grow to 4 1/2 feet in length, but I've seen individuals that I know are closer to the 5 foot mark. 

Mating occurs from April to June and often results in massive amounts of snakes congregating in one location. Large females emit a pheromone to attract the smaller males. Several males will approach a female and entwine their body around her. They will jerk spasmodically to stimulate her into breeding. Aggressive, stronger males will win the right to mate and many males may mate with a single female.

(Large mating ball in a drainage pipe at Squaw Creek NWR)

I have been making numerous trips to Squaw Creek NWR since May 4, 2012 when I discovered that the Northern Watersnakes were mating. There have been literally dozens of these snakes all over a spillway at the refuge. I was so excited to witness such a phenomena playing out for me to see. I was back up there this morning (May 21) and they were still there attracting mates. In about 3 to 5 months they will give live birth to as many as 30 offspring. 

(Juvenile Northern Watersnake)

These snakes are often mistaken for Cottonmouths and needlessly killed out of fear. While they are very feisty and aggressive they are harmless. Many people erroneously believe that you can ID a venomous snake based on the shape of the head. Not all venomous snakes have triangular shaped heads, and many non-venomous snakes do. It is not an accurate why to tell a venomous snake from a non-venomous. Just look at the definite diamond-shaped head on this Northern Watersnake, which is another reason it is often mistaken for the cottonmouth.

 I've had them come at me as if to chase me, and stood my ground and they slithered around me to escape. They would prefer to avoid confrontation and go out of their way to escape the presence of humans. If you decide to grab one you will most likely earn a bite for your trouble, or at the very least it will musk you. Musking is extremely nasty and smells horrible. It is a mixture of feces and a musk they produce that is guaranteed to earn the snake some distance and safety from being bothered or eaten by a predator who can smell the terrible odor. Although stinky, they are still preyed upon by raccoons, foxes, coyotes, snapping turtles, opossums and aerial predators like hawks.

A young friend of mine went to the refuge with me the other day and decided to try his hand at catching one of these ornery snakes. He chose a large female and soon discovered how fast and feisty they truly are. It struck at him numerous times and narrowly missed nipping his nose at one point. I admire his fearless nature and love of these animals though.

These snakes are often encountered by people while camping, kayaking, canoeing and fishing. Many are killed and discarded because of their aggressive nature and their similar appearance to the venomous cottonmouth. I would ask that we restrain ourselves and tolerate the presence of these snakes as being an important part of the aquatic habitats they occur in. They perform a service in the form of consuming dead, decaying or sick fish. They will only bite if handled. If you leave them alone they will surely leave you alone.