Nature Notes
by Bob Thomas
Each February, I take a field trip to the woods near Norco, Louisiana, that are on high ground in a cypress-tupelo swamp. The site has been producing oil for years. In spite of this, it is rich in all forms of local wildlife, especially a nice variety of reptiles and amphibians.
Over the years, I’ve used this trip to introduce herpetology students to herping (collecting reptiles and amphibians). The reason I choose this place at this time of year is that venomous cottonmouths (Agkistrodon piscivorus) are common, yet sluggish, since they are cold-blooded (poikilothermic) and are just coming to the surface after spending the cold winter underground, often in crawfish burrows. Their torpid condition renders them less dangerous to novice herpers.
Our local reptiles and amphibians do not “hibernate,” they brumate. Animals that hibernate slow their metabolic activity to the point where they are in a very deep state of torpor. Our brumating herps (reptiles and amphibians) slow their metabolic activity in response to low temperatures, but they are still active, just slower. As an example, if you found a hibernating animal and placed it on a table in your kitchen, it may take hours to see the first sign of life. A brumating animal, however, would immediately start moving and within minutes be moderately active. Even the classic “hibernating” animal, the bear, brumates. They have their young while in this condition and adequately care for them.
When visiting our collecting site, we simply walk the roads and turn logs, timbers, and discarded debris looking for concealed critters. If the weather is relatively warm, animals that have spent the winter well underground in cracks, crevices and burrows will come up under logs and other structures lying on the surface. They absorb a bit of heat that passes through the structure, yet are protected from surface predators while in their vulnerable indolent disposition.
We find many frogs, including pointy-nosed narrow-mouth toads (Gastrophryne carolinensis), green tree frogs (Hyla cinerea, Louisiana’s state frog), squirrel tree frogs (Hyla squirrela), cricket frogs (Acris crepitans), bronze frogs (Rana [Lithobates] clamitans), and Gulf coast toads (Bufo [Incilius] nebulifer). All move slowly due to the low temperature, and their patterns are darkened due to the cool habitats causing the expansion of amoeboid melanophores in their skin blocking the expression of other colors.
Typically we find many anoles (Anolis carolinensis) under logs and often under bark on dead trees. They are green when active during the warmer months, but dark brown when brumating or inactive in hiding places. They also change colors by expansion and contraction of melanophores.
Periodically, we find five-lined skinks (Plestiodon [Eumeces] fasciatus), ground skinks (Scincella laterale), and the occasional broad-head skink (Plestiodon [Eumeces] laticeps).
But the main targets for herpers are the snakes. It is so cool to turn a huge timber and find neatly coiled snakes tucked away in little depressions in the soil or crevices in the timber. We commonly find eastern ribbonsnakes (Thamnophis proximus) and broad-banded water snakes (Nerodia fasciata), but occasionally we are treated to a beautiful red and black juvenile mud snake (Farancia abacura). What a treat that is.
Of course, there is la cible spéciale, the cottonmouth. Although they are sluggish, we often get the flash of the pale mouth lining (hence the name), often with a slight elevation of the fangs, that reminds us to be careful where we put our hands. These animals are cryptic, relying heavily on their camouflaged dorsal pattern. Over the years, I’ve grabbed something under a log only to realize that there was a nearby coiled venomous snake. Interestingly, these animals instinctively know they are well concealed and they tend not to strike until actually touched. Whew! I’ve been close, but, knock on wood, have not been tagged yet.
There was a day when, as a scientist, I collected every herp I found. With the continued demise of habitat and other pressures on populations, there has been a continual decline in the distribution of many animal species and numbers of individuals. On our field trips now, we find critters, photograph them, sit and enjoy watching them, then neatly replace the log (after moving the animals to the side so they don’t get crushed), and leave them in the wild.
This is a pleasurable way to spend a few hours on a sunny late winter day, welcoming my scaly and slimy little friends back to their active world.
Excited children watch a just discovered baby By simply rolling a log, one might find a pair
broad-banded water snake (Nerodia fasciata). of eastern ribbon snakes (Thamnophis
Photo by Bob Thomas. proximus) resting before beginning
their active warm season.
Photo by Bob Thomas.
One of the target animals on this trip is the What is better than finding a cricket
venomous cottonmouth (Agkistrodon frog (Acris crepitans) with a nice green
piscivorus). This specimen was hiding under stripe on its back?
a piece of metal sheeting and is still moist Photo by Bob Thomas.
after emerging from a crawfish hole where
it spent the winter.
Photo by Bob Thomas.
Well, maybe its more fun to hold South Louisiana's cypress/tupelo swamps
your first snake! are beautiful, relaxing, and just full of
Photo by Bob Thomas. interesting critters.
Photo by Bob Thomas.