In the swampy bayous of southeastern Texas live some of the most ancient predators on the planet. Stealthy nocturnal hunters lie beneath the surface of the black water, their presence betrayed only by a crimson orange eye shine reflected from our headlamps. These animals have been here long before us, and they will likely be here long after we’re gone. It’s their territory and we must do well to respect it. We are here to study these animals, to better understand their ecology, and moreover to understand the effects of human activity on these apex predators. But in order to do that we must first catch them, an endeavor which is no task for the lighthearted.
This year I returned to graduate school at Texas Tech University to begin my master’s degree in biology. I have been taking classes, teaching, and readjusting to life in a college town. However, just because you’re in academia doesn’t mean you can’t still have fun in the field! I joined the Densmore Lab in the Biology Department, where my lab mates and I study the ecology of reptiles. Much of our work focuses on the genetics, distribution patterns, and ecological toxicology of alligators and crocodiles. My colleagues’ work is truly fascinating, and it’s an honor working with such talented scientists!
At the end of the spring semester my lab mate, Todd Bollinger organized an expedition to southeastern Texas to capture and take small tissue samples of American alligators to study the concentrations of heavy metals that accumulate in their bodies through the environment, as well as to examine their population genetic structure. This research project complies with all necessary permits and IACUC standards, and we received permission from the park administrators and the local game warden.
On the morning of our departure, we packed up the truck and drove the 8 hours to Houston where we unloaded our bags at the little apartment we’d be staying in, and then drove another half hour to our field site where we would be out all night working. Upon arriving at the site at sunset, we prepped our gear and began walking along the trail surrounding the tranquil lakes. Spanish moss hung lazily from the treetops and lightning bugs flickered intermittently through the heavy air. The wildlife here was exceptional – armadillos and raccoons scurried through the brush, white-tailed deer barked in alarm as they bounded through the forest, and a menagerie of herons, egrets, ibis, and spoonbills regularly flew overhead. But of course the real highlight was seeing my first wild alligators!
I’ve had a fascination with crocodiles and alligators as long as I can remember, due in no small part to watching Steve Irwin on television when I was a child. Having never visited the Gulf Coast before, I had never had the chance to see these amazing animals in the wild. Alligators are found only in the subtropical regions of the southeastern USA from roughly North Carolina down to southern Texas (with a few fringe populations occurring in southern Virginia and northern Mexico). They are specifically adapted for the lakes, rivers, swamps, and bayous of this area, often serving as the main apex predators of these aquatic ecosystems.
The first animal we caught was an adult female, about 6 feet long and just over 100 pounds. As my colleagues pulled her up on land I stood mesmerized for a moment admiring the sheer ferocity of this perfectly evolved predator– her violent thrashing, her impressively athletic death roll, and the guttural hissing sound she made to express her deep agitation with us. After about a minute she calmed down enough for someone to swiftly jump her and secure the head. I quickly followed suit behind, securing the hindlegs and tail. We taped her jaws shut, covered her eyes to calm her, and used rope to tie her legs in a way that made it safer for both her and us while we measured her and took blood and tissue samples.
I was amazed at how strong she was, as even while two people restrained her, she would occasionally erupt in a bout of violent thrashing and we’d have to literally wrestle her down to prevent her from throwing us off her back. And this wasn’t even a large individual! We all worked quickly and efficiently to minimize the amount of time spent with the animal, as alligators cannot withstand prolonged periods of stress due to the lactic acid that can build up in their muscles.
After we finished collecting data and obtaining tissue samples, we carefully removed the ropes and tape and released her facing the water, where she slowly but surely lumbered into the abyss, disappearing from view.
We worked four nights, capturing as many alligators as we could. Most nights we noosed animals from the shoreline, mimicking hatchling calls to entice the curious, larger adults to come closer to us. However, one night the game warden gave us a ride in his fan boat so we could capture animals out on the open water.
I had never ridden a fan boat, and it is literally just what it sounds like: a gigantic fan attached to the back of a boat. This allowed us to cruise through the shallow inlets and bayous with ease, giving us access to many areas we would not otherwise be able to reach on foot. On this night we also managed to catch a few juveniles, which of course are much easier to handle than the adults!
One night we managed to capture one of the largest males in the area, which turned out to be quite the endeavor. As we tried to entice him to come closer to shore to make the catch, he charged through the water in a show of territoriality. After we got the ropes around him, it took all five of us to haul him out of the water, and it was exhausting work to restrain him.
Even with the jaws secured shut an irate alligator can be potentially dangerous, easily snapping bone with a single swipe of its tail. It initially took four of us using all our body weight to pin the animal down until he tired out and we could safely take some measurements. He measured just over 11 feet, and was too heavy to weigh, though we estimated him to be between 300-400 lbs! He was truly an impressive beast– a primal relic from the age of giant reptiles.
Despite spending only a small amount of time working with these animals, I learned so much about them. They surpassed my expectations for their might and agility, and having the chance to get up close and personal with them gave me a whole new appreciation and respect for these perfect predators.
The scientific research conducted in our lab on this population of alligators will provide us with a better understanding of how they fare both inside and outside of the protected area, and will give an indication on the levels of environmental pollutants in their bodies, and in the ecosystem as a whole. Overall our trip was quite successful, and future expeditions will continue to obtain critical data on these amazing creatures.