By Anna Heiney
NASA’s Kennedy Space Center, Fla.
Ancient creatures are prowling the complex network of waterways at NASA’s Kennedy Space Center.
Sometimes they’re barely visible, their positions given away only by the telltale pattern of their eyes and noses breaking the surface of a pond or canal. They’ll also lounge on riverbanks, basking in the sun, wearing a wide, toothy, menacing “grin.”
The American alligator (Alligator mississippiensis) is a longtime resident at the coastal spaceport, which shares boundaries with the Merritt Island National Wildlife Refuge on Florida’s east coast. Generation after generation of the enormous reptiles has called the area home.
This is a unique population that spends a large amount of time in an estuarine environment.
“These alligators don’t leave this area. This is a great habitat for them,” said Russell Lowers, a wildlife biologist with InoMedic Health Applications at Kennedy.
“Hardly anyone has fished out here for 50 years, so they have some of the best food resources available. They also need freshwater sources, because unlike a saltwater crocodile, which has a salt-secreting gland, an alligator must have access to fresh water to survive.”
Although they typically choose to stay in or near the water, alligators still are a common sight to employees and visitors. They’re often spotted crossing roads, sunning themselves on runways, venturing into parking lots or wandering a little too close to buildings. For example, a large alligator briefly stopped afternoon traffic in 2011 as it crossed a busy intersection in the Launch Complex 39 area.
Despite their frequent appearances, the beasts are surprisingly mysterious. Lowers and several colleagues around the world have been working since 2006 to learn more about their reproductive and feeding habits, how changes in the climate and environment affect them, and how they impact the other animals in their ecosystem.
Through hormone analysis, they’ve learned that the estuarine alligators living at the refuge nest once about every three years, while the inland or freshwater populations typically nest every other year. These animals typically build nests in the same general area where they’ve nested in the past, producing, on average, about three dozen eggs per clutch.
The babies’ genders depend on the temperature of the eggs during a critical time in their incubation period. Temperatures below 31.5 degrees Celsius, or nearly 89 degrees Fahrenheit, produce more females as the temperature drops; temperatures above that point result in more males. As average temperatures rise, alligator populations may become increasingly male.
Once the young hatch out, their mother will supervise and care for them for a year or two to help protect against larger, cannibalistic males.
The American alligator sits at the top of its food chain — an “apex predator.” That’s part of the appeal in studying them, Lowers explained.
“They’ll eat anything in the environment. Small mammals, fish, turtles — you name it, they eat it,” he said. They’re like a little chemistry set.”
In fact, Lowers said, that is what they currently are studying. About once a week, he and his colleagues will make the rounds, visiting different watering holes around the space center to capture alligators larger than five or six feet in order to obtain blood, urine and tissue samples. Once they locate an animal, Lowers pulls it onto the bank using an animal snare, secures its mouth with tape, and quickly works to gather the necessary samples. This whole process is done while the animal lays calmly on the bank with a towel covering its eyes.
“You’ll see people catching alligators on TV, but this is nothing like that,” Lowers said. “You catch a gator, you pull him on the bank, and he sits there while you take a blood sample, urine sample and tissue sample. In 15 minutes, he’s done. There’s no wrangling and jumping around.”
The shorter the process, the easier it is on everyone involved — the alligator most of all. On hot, sunny days especially, it’s important to let the animal get back to the water where it can cool off.
Lowers believes if the process looks easy, he’s done his job right.
“It’s like taking someone to the doctor’s office,” he explained. “You want to take them in, get their blood drawn, let them pee in a cup, step on the scale, and let them walk out the door.”
Blood samples will reveal long-term environmental contaminants, while pesticides and herbicides are found in urine. Radioactive isotope analysis on the tissues will help determine specifically what the animals are eating.
One of the biggest mysteries remaining among Kennedy’s alligators is seemingly one of the simplest: How many alligators live here? That answer is determined more by statistics than by catching, tagging or biological specimen-sampling.
“It’s the number-one question people ask,” Lowers said. “But nobody really knows.”
The refuge encompasses 140,000 acres, which are evenly divided between land and water, according to Lowers. Since many areas are inaccessible to humans but could potentially contain large numbers of alligators, there is no surefire way to estimate the population.
This mystery may puzzle the biologists and ecologists studying the animals but for the alligators, it’s just one of the many benefits of living here. Since they generally stay away from humans, those remote areas offer a lot of space for the animals to be themselves — wild and undisturbed.
Lowers, a scientist in the KSC Ecological Program, works among a group of colleagues at organizations and universities within the U.S. and around the world who are focused on learning more about alligators and crocodiles with the goal of understanding the way ecosystem health reflects human health.
“This is a cooperative project,” Lowers said. “We have probably a multimillion-dollar study being done with a very limited budget; people around the world are matching their time and instruments.”
In addition to KSC, crocodilian samples for the study are being collected in South Carolina, Belize, and South Africa. Samples are processed by a variety of laboratories including the Medical University of South Carolina, Centers for Disease Control, National Institute of Standards and Technology, and the Center for Marine Environmental Studies laboratory in Japan, and the University of Florida in Gainesville. Researchers at the different laboratories are focusing on topics related to their expertise, including the effect of emerging contaminants such as flame retardants and plasticisers on the endocrine and reproductive system, response of the thyroid gland to organ-metals and more. Much of this information is directly related to human health and wellbeing.
As launch vehicles, components, facilities and chemicals change, the alligator is like the canary in the coal mine — a sentinel species giving us indications of environmental changes at the spaceport as they happen.
“If the alligators are healthy, the other animals should be healthy,” Lowers said. “And that means it’s a safe place for animals to live, and for people to work.”