Wildlife Watching in America's National Parks: A Seasonal Guide

10. December—American Alligators of the Everglades

163 10 { December American Alligators of the Everglades Winter in the everglades sounds like an oxymoron, but there is indeed a noticeable winter season. Instead of snow and subfreezing temperatures, relative dryness and pleasant temperatures characterize the region (versus the steamy heat of summer). Winter in the everglades is also characterized by increased biodiversity as northern migrants join the resident wildlife. Scores of wading birds and waterfowl seem to occupy every waterhole. And lurking in the water and along the shores are the ubiquitous alligators, waiting for a chance to lunge at unsuspecting prey. Far from being a quiet season, December in the everglades can be action-packed. What’s Remarkable about Alligators? Almost all aspects of the American alligator are fascinating, from their bone-crunching jaws to their hundreds of millions of years of evolution to their unique anatomical and physiological features. One particularly odd alligator characteristic that is both remarkable and cause for conservation concern is the fact that the temperature of the nest almost solely determines the sex of newborn alligators. If the nest temperature is 86 degrees or lower all of the young will be female, whereas if the nest temperature is 93 degrees or higher all of the young will be male (nests in the midrange can produce both sexes). The primary determinant of the temperature seems to be the material the nest is built of. Nests constructed of 164 | Winter leaves tend to be hotter than those constructed of moist marsh vegetation. Over their hundreds of millions of years of evolution alligators have somehow managed to find a nice balance, so there’s always enough males and females to keep the species going. But what happens under climate change? Could we end up having all male young, or will the alligators adjust by using moister and cooler material to construct their nests? Alligator Ecology The American alligator is a survivor. For about 200 million years they’ve persevered, while other reptiles, including the mighty dinosaurs, disappeared from the face of the earth. The alligator has been rightfully referred to as a living fossil, and seeing one is perhaps the closest any of us will ever get to a time machine. Of course, part of what makes alligators so fascinating is their teeth, their jaws, and the way they patiently wait for prey. A favored hunting tactic is to float like a water-soaked log with only eyes and nostrils exposed above the surface. In this position they can wait motionless for hours until prey comes close enough for an attack. Science recently discovered that alligators have a sixth sense located in nodules on the rim of The recovery of the American alligator ranks as one of the country’s greatest conservation stories. (Photos by Gary W. Vequist) 165| December–American Alligators of the Everglades their jaw that serve as water-motion detectors. If the sensory organs detect prey within striking distance the alligator lunges and snaps in an effort to catch the unsuspecting prey. This hunting method is especially useful in catching fish, which often constitute a large portion of their diet. In addition to fish, alligators will eat almost anything, including other alligators in a cannibalistic battle to the death. even turtles with their hard shells are on the menu, although it’s not uncommon to see a gator bite off more than they can crunch when they take on a particularly large turtle. Wildlife watchers can sometimes see a gator holding a large turtle in its mouth for hours—as if trying to decide what to do next. However, in most cases all one sees of an alligator predatory attack is a flurry of splashing, a few swift chomps, and then the alligator throwing its head up in the air to swallow its prey. With larger prey it may take longer as the alligator, or alligators, have to tear, crunch, and pull the prey apart using the infamous “death roll.” Much like the wolves in Yellowstone, alligators are at the top of the food chain, and their presence has a ripple effect throughout the ecosystem. For example, a significant prey item of alligators is the prehistoric-looking spotted gar (a fish). When alligators are abundant few spotted gar survive long The American alligator can grow up to 19 feet long and weigh a half a ton, making it a top predator wherever it is found. (Photo by Gary W. Vequist...