There are a lot of carnivores in the marsh. They range from microscopic animals, to plants such as bladderwort, and on up through the various species of fishes, reptiles, birds and mammals. Unless we are accustomed to thinking of creatures in such terms, we are liable to consider as predators only the obvious ones—the bobcats, snapping turtles, wading birds and so forth. The term, however, properly refers to any plant or animal that makes its living capturing and eating critters. Although we don’t usually apply the term to plants, the pitcher plants, sundews and several of the bladderworts—along with the well known and increasingly endangered Venus’ Fly-Traps—definitely qualify as well.
Without doubt, the best-known predator of southern wetlands is the American alligator (Alligator mississippiensis). The name “alligator” is derived from the Spanish el legatro, “the lizard,” and when a ‘gator is available for comparison, all of the neighborhood lizards fade into insignificance.
‘Gators are interesting critters. They’ve been around for about 80 million years, predating all but the earliest dinosaurs, and are the closest things to true dinosaurs currently roaming the planet. Even if we accept that birds are descended from dinos, the necessary pelvic structures for walking upright didn’t occur until about 10 million years after the alligator tribe was well-established, making the descendants of the bipedal saurians dinos-come-lately indeed.
Although they look similar, the alligators split away from the other crocodilians way back when, and continued virtually unchanged while crocodiles and their closer kin continued to evolve into the many species found around the world today. Alligators, like sharks, were so well-adapted to their environment that there was no need to update the design, and todays ‘gators are virtually identical to the fossils of their ancestors in everything but size. Proto-alligators sometimes reached lengths of thirty feet, (9.1 m) whereas today a ‘gator over twelve feet (3.7 m) and about 500 lbs. (227 kg) is unusual. The modern record is supposed to be nineteen feet (5.8 m); however that specimen, captured near Jacksonville in the 1890’s, is believed by many herpetologists to have been a American crocodile that ventured farther north than usual, as are the twenty to twenty-two footers described by William Bartram. (Crocs are still found in Florida, but are confined to the mangrove swamps surrounding the southern shores of the peninsula. About 500 are believed to remain in the state.)
Like other modern reptiles, alligators are cold-blooded–they cannot sustain a constant body temperature by metabolism alone. For that reason, although they can survive long periods of cold by resorting to aestivation (similar to hibernation), they inhabit only areas in which the water temperature remains at or above 70° F. ( 21° C) for substantial periods. At lower temperatures the ‘gator’s metabolism slows, along with its activity, to the point of making it uninterested in doing business. They further control their body temperature by lying in the sun or submerging in the water. For that reason, they do not do well in extremely hot climates either. Worldwide, alligators are confined to two species, A. missippiensis in the lowland regions of the southeast United States, and a relative, A. sinensis, found in very small numbers in China’s Yangtze River.
“Oh, look—that bird is right by his head! Why doesn’t he eat it,” people often remark when first seeing a ‘gator in its natural habitat. Adult alligators only need to eat once, perhaps twice a week, and have been known to go as long as two years without food. That’s because cold-blooded critters need less to eat than those who are busily burning up their calories with temperature regulation, but it is also due to the fact that–except for hunting and making little alligators–they actually do very little. Sunning and cooling off in the water take very little energy. An alligator will eat a bird if it’s hungry and the bird cooperates, but the birds can generally tell when a ’gator is in hunting mode, and will keep their distance.
Alligators are ambush hunters, so even food-gathering is merely a matter of submerging until only their snouts and eyes are above water, then waiting for a hapless fish, turtle, raccoon, marsh rabbit or the like to wander within range. Then, with a thrust of its powerful tail, the ‘gator will lunge and grasp the prey in its equally powerful jaws. (‘Gator jaws been found able to exert pressures of up to 2,000 p.s.i.) Alternatively, depending on the location of the victim, the reptile may sweep it into the water with its tail, then dispatch it by grasping it in its jaws and rolling over and over in the water until the prey ceases struggling or is torn apart.
Legend has it that an alligator can outrun a man. Overall, that is not true. A man—and especially a frightened man—can easily hit 15 mph (24 kph) for fairly long distances. An alligator, on the other hand, is only good for about 10 mph (16 kph) in short sprints, and thus the race is usually won by whoever starts first.
That is less of an issue than most people think. Like most successful predators, alligators rarely pick on prey anywhere near their own size. There is always the danger that large prey may injure the predator, and you don’t last for 70-odd million years by making decisions that can get you hurt. In general, the average weight of a predator’s natural prey tends to be roughly one-fifth to one-quarter of the average weight of the predator. (The notable exceptions to this are the big cats, which routinely put down prey their own size or larger—but in that case we are talking about the most efficient land hunter, pound for pound, on the planet. The other exceptions are predators who hunt in packs.) Thus, it would take a pretty large ‘gator to be a consistent danger to a grown human. The problem, as with sharks, arises when the predator cannot discern the size of the prey, such as in murky water or at night. Still, one need not be too concerned about the smaller ‘gators, and then only if they happen to be hungry that day.
American alligators were hunted to a dangerously low level up until the 1960’s, when effective protection was put in place. Some authorities believe that alligator numbers were further reduced by the effects of DDT and its metabolites, but this has only been shown to have occurred in Lake Apopka, in Central Florida, a large lake with no outlets to disperse the buildup of pollutants. In an y case, alligators have rebounded remarkably throughout their entire range, and today may be legally hunted for their hides and meat, subject to strict limits and licensing. (In case you were wondering, ‘gator tastes like fishy chicken, but tougher.) Limits do not apply to farmed animals, and there has arisen a small but profitable farming industry in the southern states.
After mating in the spring, the “bull” gator goes about his business. The “she” gator builds a nest of vegetation, piling it up in a mound about three feet (.9 m) high and six to seven feet (1.8-2.1 m) in diameter. She then digs a hole in the center of the pile, and deposits between twenty and forty eggs. After covering the eggs, she remains in the area of the nest to protect it from marauding raccoons, mink or other scavengers. As the vegetation rots, it produces heat that incubates the eggs.
Nest temperature determines the sex of the young. If the nest is below 30 degrees Celsius (86 F) all are female; above 34 degrees Celsius (93 F) all are male and temperatures in between will produce both sexes. Alligators are careful–if not caring–mothers, and will stay with their brood for up to a year to protect them from the many predators that threaten the smaller residents of the wetlands. Once they are about a year old they are left to their own devices, and by the time they have reached a length of around four feet (1.2 m.) they will have no dangerous enemies apart from larger alligators and man.
Alligators are not just hangers-on around the marsh. Under certain conditions they can be the most important of all its citizens. Female ‘gators maintain “’gator holes,” water-filled depressions that are often surrounded by a ring of shrubbery growing on the debris that the animal has thrown out of the hole while keeping it free of vegetation. Over time, these holes may reach depths of several feet below the surface of the land, and in dry periods may hold the only surface water remaining over a large area.
“Gator holes” are a critical factor in the survival of fish, turtles and other aquatic creatures, providing a valuable source of water for terrestrial animals, as well. The ‘gators get a hole to stay cool in, a refuge for their young, and food for the asking. Even so, many of the creatures sheltering in the holes survive to again populate the surrounding area when the rains return. This system of concentration and re-population from alligator holes is the major mechanism by which aquatic animals survive the six months of dry weather that are the norm in Southern Florida, and it has become even more critical over the past century’s diminishing of the Everglades water supply.
Y’all be careful now, y’hear? And keep that yappy little dog on a short leash. Us Crackers call walking dogs along the edge of the lake “trolling.”
[A few words about spelling—the slang term ‘gator, when referring to a large saurian, is always spelled with an apostrophe. The non-apostrophe “Gator” refers to the sports teams and students of an inconsequential southern college located 700 miles southeast of Lexington, KY, home of the Wildcats.] :p