As promised, Gus and his gator kind have a fascinating existence and history. From Diane Ackerman’s The Moon By Whale Light:
Crocodilians, birds, and dinosaurs had a common origin about 230 million years ago, in the Mesozoic Era. Today, there are 3 groups of crocodilians: crocodiles, alligators, and caimans/gharials. But it is easy to confuse the three main types of corcodilians… Here are some rules of thumb: Alligators have round snouts, wheras crocodiles have pointed, triangular snouts. Alligators’ nostrils have a space between them and look like an open V that doesn’t meet at the bottom (wheras crocodiles’ nostrils are closer together). Alligators have much less agressive personalities. If you can see both upper and bottom teeth, it’s probably a crocodile; but alligators have more teeth (eighty) than crocodiles do (seventy). Gharials are mild-mannered, fish-eating crocodilians with long, slender, graceful snouts and sometimes, a big knob right at the end. And caimans look like alligators but have short, blunt noses. Within the order of crocodilians, there are about twenty-nine different forms.”
In order to “sex” an alligator, one must check out the slit under its tail, called the cloaca, a cavity in which the sex organ lies. Males have penises and females clitorises. Gus could be Gracilia, but I won’t personally be researching such a thing.