• Image about Louis Guillette
Carmen Mok

Sure, they’re among the world’s most feared predators, but to scientists, the mystique that surrounds alligators has to do with more than just their above-par hunting skills.

Perched in an airboat with the motor droning in the background, Louis Guillette, Ph.D., skims across a Florida marsh on a dark, moonless night. Guillette, chair of Marine Genomics at the Hollings Marine Laboratory in South Carolina and a former professor of zoology at the University of Florida, and his two colleagues are seeking alligators. Baby or adult (they can grow as long as 14 feet), it really doesn’t matter to the men — as long as they find a few. “There’s a bit of adventure and charisma in studying them,” explains Guillette, likening the reptiles to the great white shark in terms of the mystique they have in compelling our attention.

On the occasion of finding an alligator (spotted by shining an enormously bright flashlight into the darkness), Guillette and his colleagues will slip a noose around its neck, tape its jaw shut and wrestle it into the airboat.

They will then measure the animal and give it a checkup, “similar to the one you get at a doctor’s office,” Guillette says. Among other things, the exam includes taking samples of both blood and urine, the latter of which requires the use of a dog catheter. But why, you might be wondering, would anyone be concerned about the health of such a vicious animal — arguably one of the world’s most notorious eating machines (who could ever forget Michael Vartan battling the mother of all gators in the campy film Rogue)? In Guillette’s case, he and his crew are out to check on the health of the animals because Guillette considers the alligator to be a sentinel species. Like canaries in coal mines, alligators can exhibit warning signs of environmental contamination that can threaten human health, and these exams monitor that. But in addition to their being a gauge for the status quo of our environment, the lure of studying these top predators also lies in scientists’ desires to better understand the animals’ fearsome hunting skills, to shed light on evolution and, in some cases, even to fight disease.

The American alligator is one of nearly two dozen species of crocodilians — the scientific name for the animals of this group. Beyond North America, other varieties make their homes in Asia, Africa and South America. Regardless of size, location or type, one thing about them remains the same: their ability to kill.

Understanding the intricacies of this skill is what interests Daphne Soares, Ph.D., assistant professor of biology at the University of Maryland. What do alligators have that allows them to be the “top dog” in their environment? The answer, she says, lies in their nervous system.

“Alligators have evolved to be excellent predators,” Soares says. “They have keen eyesight and hearing, and, on top of everything else, they have this very sensitive tactile organ that can detect ripples in the water,” referring to the bumps on the alligator’s long, menacing jaw. This ability to detect ripples is one of the many facets that makes the alligator so deadly — it instantly alerts the animal that potential prey has entered the water.

While studying this aptitude to detect prey has helped shed light on how these beasts are (and remain) at the top of the food chain in their environment, recent research into the alligator’s respiratory system now reveals a better grasp of its evolutionary path. C.G. Farmer, Ph.D., an evolutionary biologist and assistant professor of biology at the University of Utah, reported this year that alligators breathe like birds. While humans have what can be called a tidal pattern of breathing (air comes in and out), alligators and birds have a unidirectional airflow: Air comes into the lungs, makes a circuit and goes back out. Previously, scientists had thought that unidirectional airflow was unique to birds. Yet, according to Farmer, it makes perfect sense that alligators have the same unidirectional breathing pattern. While alligators dwell in swamps rather than soar through the sky, they are, in fact, related to birds. Both birds and alligators trace their lineage back to a common ancestor — the archosaur — from the Triassic period, about 250 million years ago.

Theories of animal evolution aside, in addition to its prowess in the water, the alligator’s immune system is another contributing factor to its ability to remain king of the swamp — especially considering that very little seems to affect the beast. And this is what first attracted Mark Merchant, Ph.D., an associate professor of biochemistry at McNeese State University in Louisiana, to study the animal. Merchant, who grew up around alligators in southwestern Louisiana and southeast Texas, often noticed that despite serious wounds — even missing limbs — the alligators were able to survive, if not thrive, in an environment swarming with nasty microbes.