Story and Photos by Gabe Giffin
In a longleaf pine forest in north Louisiana, there’s a moment of suspense for biologist Beau Gregory each time he lifts the lid on a snake trap. For most, the suspense would be the fact that you are about to open a snake trap. For Gregory, he knows snakes will be there, he just hopes the right one.
Over the last few years, Gregory along with a few other biologist have checked snake traps on a weekly basis hoping to find one snake in particular, the Louisiana pine snake (Pituophis ruthveni). The suspense primarily comes from the rarity of finding a pine snake in his traps. As the lid lifts up and we peer in, our suspense is met with the feisty coachwhip snake that now must be wrangled and released, and the dissatisfaction of a trap without a pine snake.
Louisiana pine snakes spend a majority of their lives underground, primarily due to the species they prey on the most, a Baird’s pocket gopher. The pocket gopher spends almost all of its life underground digging and maintaining its underground burrows. The pickle-sized rodent plugs its burrow holes making it difficult for predators to enter.
On the sandy bottoms of a longleaf pine forest, it’s easy to see the mounded path of a gopher burrow. The disrupted soil forms a small mound about 2 inches high and 5 inches across. The mound continually meanders through vegetation, crossing dirt trails and sandy roads. Follow the path of these windy trails and they lead to a plugged hole, unless the pointed snout and muscular body of a Louisiana pine snake has just entered.
The pine snake’s head is perfect for penetrating into the gopher mound. The narrow snout allows the snake’s nose to become a tool to gouge into the burrow. Once in the burrow, the snake will move past the gopher before expanding its body and trapping the gopher against the walls of its burrow. Although the pine snake is a constrictor, it’s believed they use this method in burrows as opposed to the lasso method of many constrictor species. Afterward, it is thought that the snake will remain in the burrow until it is hungry again. This characteristic makes it hard to determine how many pine snakes are out there.
The rarity of finding this snake has always been there, after all, it wasn’t until 1920 that they were first discovered. In the late ‘40s, a survey was conducted at now Fort Polk and Red Dirt Wildlife Management Area and only two were found. By 2000, it was estimated that fewer than 180 Louisiana pine snakes had ever been found in the wild. Around this time the U.S. Fish and Wildlife Service (USFWS) began preliminary discussions on possibly listing the snake on its Federal List of Threatened and Endangered Species, citing it one of the rarest snakes in North America. This did not place the snake on the list, but raised concerns that this could become possible.
Once funding was made available the first research on the pine snake was accomplished. Craig Rudolph of the Southeastern Forest Research Station established a trapping study by scattering dozens of 4-by-4 foot box traps about the area. All four sides of each trap had a cone-shaped funnel that led into the box, with 50 feet of hardware cloth drift line leading out in four directions. The intent was to intercept a snake and direct it toward the funnel as it follows the fence line.
Subsequent studies using radio-telemetry showed that the pine snakes spend up to 90 percent of their lives in pocket gopher burrows within a few inches of the soil surface. They are active from April to November, and eat primarily pocket gophers supplemented with the occasional hispid cotton rat or other small rodent. While the snake is quite large, the females lay only three to six eggs. The eggs themselves are large, roughly the shape and about the size of a small hotdog.
These studies were a good start to help solidify a few speculations on the snake, but there was still more that needed to be learned. The population was still unknown, and less than 75 snakes were tagged with passive integrated transponder (PIT) tags for density studies. Furthermore, learning that pocket gophers were their main choice of prey, it was important to look at the habitat type of the gopher and the snake.
As one takes the drive up I-49 and eventually on main roads like Highway 167, it’s hard not to notice the large stands of pines in Kisatchie National Forest. Continue north and the occasional clear cut or thinned forest speckles the landscape. Between looking at the forest and the road, you’re bound to see a few log trucks. The timber industry is what this area knows and if the sights don’t show it, roll the window down and smell the sweet sap of pines mixed with the morning dew, this industry is all around you.
Historically, longleaf forest once covered vast amounts of acreage throughout western and north central Louisiana. Land use changes, urbanization, demand for forest products and changes in forestry operations have prompted both public and private landowners to convert longleaf forests to faster growing species such as loblolly pine. Loblolly pine is generally planted as pure stands in rows similar to agricultural row crops. The trees are quick to “shade out” the forest floor which produces undesirable habitat conditions for the pocket gopher.
Typically, longleaf pine forests have lower stocking rates than plantation forests allowing more sunlight to reach the forest floor which permits nutrient poor soils to dry quickly creating xeric conditions. This lower stocking creates “patchy” conditions with natural openings throughout the stand. These small openings, coupled with the dry conditions, make the soils penetrable which is perfect for the pocket gopher and the pine snake. However, a longleaf pine forest normally remains in a “grass stage” for the first two to seven years. Additionally, it normally requires prescribed burning in order to move it out of the grass stage and into a more mature growth rate. This can cause concern for residents living near forest stands that require burning.
Back in north Louisiana, Gregory checks trap number 17 of 20 only to be met with a rat snake. Each day a trap is open for business is considered a “trap day,” with 20 traps set, each day signifies 20 trap days. Currently Gregory is finding one pine snake about every 400 trap days. “I’d like to think there are more pine snakes out here,” says Gregory, “but we need more traps or a more efficient detection method.”
When a pine snake is trapped it is checked for a PIT tag, if the snake has not received one yet, it becomes another snake added to the grand total of pine snakes caught and tagged. The tag will help determine if the snake is a recapture as well as give biologists an idea of how many snakes are living in the study area. Along with tags, the department is attempting to photograph each snake. Unlike some species, pine snakes vary in coloration on their heads and Gregory has yet to see two patterns that resemble one another identically.
Traps aren’t the only measures the department and its research partners are taking though. Recently a few automated PIT tag readers were placed in a suitable habitat for the snakes. The hope was that tagged pine snakes would slither by the transmitter pinging its receiver. “I was a bit apprehensive about the potential for success because it was such a long shot, but so far we’ve already had a couple of snakes register,” said Gregory. This sends valuable information about the snakes movements and survival, while also saving time and money.
FINDING THE BALANCE
As mentioned before, the Louisiana pine snake is a candidate for placement on the Federal List of Threatened and Endangered Species and this status is due to be reassessed in the near future the Louisiana Department of Wildlife and Fisheries (LDWF) Natural Heritage Program addresses species that are either listed or approaching becoming listed under the USFWS Endangered Species List. Currently different groups are coming together to work on stabilizing the species and its habitat. A cooperative agreement between multiple federal agencies, LDWF, and Texas Parks and Wildlife Department has already been signed. The agreement establishes a network of people interested in securing the future for this rare animal.
A pilot reintroduction project has also begun with several zoos captive breeding pine snakes. When the eggs hatch, half of the snakes are released into the wild within days of birth, while the others are fed and kept until the following spring for release, a process called head-starting. The expectation is that the snake will still be young enough to adapt to its natural habitat while having the advantage of a larger size and therefore fewer predators.
Timber companies and private landowners are playing their part too. Some have forgone planting loblolly and instead planting lonleaf pines. While the return on investment is longer, the habitat it provides is worth it for the species and eventually for their pocketbooks. While there is still much to be learned about the Louisiana pine snake, the hope is that groups working together can help establish a habitat and management practice to restore this species to a manageable population. “The department and its partners are working hard now to address the needs of this snake through both habitat management and research,” said Gregory, “It would be a wonderful success story to be able to accomplish this before federal listing is required.”