Archive for June, 2011

A Flash of Blue

Friday, June 17th, 2011

During June and July, eggs of the Five-lined Skink (Plestiodon fasciatus) hatch, producing tiny black and white striped offspring with metallic blue tails. These small lizards are often common in yards, on logs in the forest, and on the sides of trees. When approached, they rapidly disappear into leaf litter or under a log. What we often see is just a blur of blue.

Juvenile Five-lined Skink

Juvenile Five-lined Skink

The black and white stripes fade as the skinks get older, and just after they reach sexual maturity, their tails fade to match the brown body coloration. Why are the juveniles so brightly colored in the first place, and why do they lose this coloration?

Adult female Five-lined Skink

Adult female Five-lined Skink

If you watch a young skink for a while, it will go in and out of leaf liter looking for small insects. When its body goes into the leaf litter, it will move the tail back and forth on the leaf litter. If a bird or other predator has been watching the lizard, the blue tail signals that the skink knows a predator is near and that it likely can escape if attacked. If the bird attacks anyway, it may get the tail but the lizard will escape and grow a new tail. Losing a tail doesn’t cost a young skink very much in terms of energy. So this is the answer to the first question. The bright coloration distracts a predator away form the body of the skink to the tail, which can be re-grown if lost.

As these skinks grow and lose their juvenile coloration, they tend to become cryptic. That is, they match the background colors of the forest and are much more difficult to see. They are also more experienced because they are older. Adults store fat in the tail, and that fat is used by males for reproductive related behavior, and by females, to produce eggs. As a result, losing a tail as an adult is expensive energetically and it can affect their ability to reproduce in a given year. They also can grow back their tails if they should lose them, but they might have to skip a year of reproduction. Consequently, the tail in adults is an important fat storage organ, so good reasons exist to not attract attention to it.

Small Yard Snakes

Friday, June 17th, 2011

Especially during Spring and Fall, we often see very small snakes, either on the sidewalks in morning or afternoon, or in our landscaping, often under rocks and other surface objects. We are talking about snakes about as big around as a pencil and usually less than one foot long. What the heck are they, and what are they doing in your yard?

The answer to the first question varies with where you live. In the immediate vicinity of Norman, Oklahoma and in most of the eastern half of the state, those small snakes are usually adults of several possible species. The first, and easiest to identify, is the Ring-necked Snake (Diadophis punctatus). It is dark gray or bluish on top with a narrow orange or yellow ring around its neck. If you bother it, it will coil its tail and turn it over exposing bright red to yellow underparts. The entire underside of the body is red to yellow with some black specks running down the belly. Ring-necked snakes eat small invertebrates, such as earthworms, spiders, and insect larvae, but they can take very small vertebrates.

Ring-necked Snake—note the obvious orange ring around the neck

Ring-necked Snake—note the obvious orange ring around the neck

If it is not a Ring-necked snake, the next thing to look for is some sort of pattern on the back of the body. If it has a pattern, then it most likely is a Brown or DeKay’s Snake (Storeria dekayi). Although the body color can vary from light tan to brown or even reddish, a lighter colored stripe will run down the midline of the back and the head will be darker than the rest of the body. However, look closely at the head and the tip of the tail, because the possibility exists that it may be a juvenile Pigmy Rattlesnake (Sistrurus miliarius). If the head is triangular shaped and it has a tiny rattle on the end of its tail, then is it a Pygmy Rattlesnake and you should leave it alone. Brown Snakes mostly eat earthworms.

Brown or DeKay's Snake

Brown or DeKay's Snake

This leaves two small snakes, both of which are solid gray on top, with no obvious markings. One will have a slightly flattened (but not diamond-shaped) head that is a tad darker than the body. It will also have very small, beady black eyes, and if you turn it over, it will have a pinkish belly. This is a Flat-headed Snake (Tantilla gracilis). These eat centipedes.

Black-headed Snake—look for the pink belly

Black-headed Snake—look for the pink belly

The last common small snake is the Rough Earthsnake (Virginia striatula). These can be very common, often several under a single rock. They are gray, brown, or reddish with no obvious markings and the belly is a light tan (never pink). These eat earthworms, slugs, and insect larvae.

Rough Earthsnake

Rough Earthsnake

So, the next time you see a small snake while working on your landscaping, give it a close look and then come back to this blog. You should be able to identify it and assure yourself that it is something that belongs in your yard. And remember, these are all about as big around as a pencil, or less!

Coachwhips—Fast as Lightning?

Thursday, June 16th, 2011

Most snakes are slow compared with how fast a person can walk. As a result, running from a snake means that you can easily put some distance between you and the snake if you are afraid of snakes. A few snakes, like coachwhips and racers are pretty fast, and they are very alert when they are warm. Coachwhips in particular, can be intimidating snakes, even though they are completely harmless.

Adult coachwhip—note the braid-like tail

Adult coachwhip—note the braid-like tail

Several years ago, a large coachwhip was spending the night in a hole inside of a shrub bed alongside of our house. When I would walk out on the porch, I would hear the bushes moving as the snake headed into the hole. I finally was able to sneak up on the snake and sure enough, it was a five-foot long coachwhip. The snake hung around for about a month, rustling about in the shrubs every time we walked by. As time passed, we noticed that we were not seeing very many lizards or frogs in our yard, most likely because the coachwhip was eating them. It finally wandered off, either looking for a mate or for more food.

Adult coachwhips vary considerably in color. Some are tan, some black, and some are almost neon orange, with no obvious pattern. They get their name because their tails look like braided whips used to regulate the speed of horses drawing coaches. Juvenile coachwhips have a barred pattern, but they are fast just like adults. Coachwhips have very large eyes and good vision, so they usually see you long before you see them. Often, by carefully looking across the top of grass in uncut fields, you can spot the neck and head of a coachwhip sticking up above the grass. They use their head like a periscope to look around as they move through the grass.

Juvenile coachwhip—note the large eyes

Juvenile coachwhip—note the large eyes

If you decide to chase one down (assuming that you are quick enough), keep in mind that they can and will bite. For the naïve naturalist, it can be quite a surprise to grab a large coachwhip only to have it chew up and down your arm while you are trying to get it under control. Again, they are not venomous, the bite really doesn’t hurt, and the needle-like teeth do not do much damage. Moreover, unlike dog or cat bites, it is highly unlikely that any infection will follow. If you don’t touch the coachwhip, it won’t bite, contrary to what you might think, so perhaps it is best to just observe it.

Finally, coachwhips have been the object of some fascinating wives’ (or perhaps husband’s) tales. This is one of the snakes that some people believe will bite their tail and roll down the hill like a hoop (hence, “hoop snake”). They don’t really do that, but it does make for a good tale!

“Kingsnakes”

Thursday, June 16th, 2011

Kingsnake is one of those snake words that is thrown around a lot. One of the most common things we hear about “kingsnakes is that they are cannibalistic because they eat other snakes. Technically speaking, kingsnakes are snakes in the genus Lampropeltis, and many species exist. They include Speckled Kingsnakes (L. getula), Prairie Kingsnakes (L. calligaster), California Mountain Kingsnakes (L. zonata), Arizona Mountain Kingsnakes (L. pyromelana) and even Milksnakes (L. triangulum).

Oklahoma has Speckled and Prairie Kingsnakes as well as Milksnakes, and all three occur across most of the state. Speckled Kingsnakes are black with yellow “speckles,” usually one on the back edge of each black scale. Prairie Kingsnakes have a background color of brown and have distinct blotches in the western part of Oklahoma but are often very drab with only a faint hint of blotches in eastern Oklahoma. Both of these can reach 3 feet in total length or more. Milksnakes have red, white, and black bands that do not extend across the belly. They usually do not exceed 2 feet in total length. These brief descriptions and the photographs in this blog, should make it rather easy for you to identify the three kingsnakes in the state.

An adult speckled kingsnake from eastern Oklahoma

An adult speckled kingsnake from eastern Oklahoma

An adult prairie kingsnake from central Oklahoma

An adult prairie kingsnake from central Oklahoma

A sub-adult milksnake from southeastern Oklahoma

A sub-adult milksnake from southeastern Oklahoma

So, what about cannibalism? It is the case that most kingsnakes eat other snakes as well as lizards, mice, and even frogs occasionally. However, the various species of “kingsnakes” usually do not eat their own species, so technically speaking, they are not cannibals any more than you or I are cannibals because we eat beef. All species of kingsnakes can discriminate between their own species and other snake species by use of a highly developed chemical sensing system. They touch other snakes with the tips of their forked tongue, bring chemicals into their mouths, and deposit those chemicals on the surface of a large and highly developed chemical sensing organ known as the vomeronasal or Jacobson’s organ. This organ transmits information to the snake brain (yes, snakes have a brain!), where the information is used to identify whether the other snake is a species that they want to eat or whether it is one of their own species. This same chemical sensing system is used to locate and identify mates during the breeding season.