Male and female alligators look similar and it can be difficult to determine the gender of one in the wild. If you are breeding alligators, telling the males and females apart is much easier when they are babies, since you can simply lift them up and turn them over to see the genitalia. Other methods of determining gender include looking for nearby baby alligators and nests. Females take care of the babies and they are never far from their young.
Measure the length of a full-grown alligator. Males can grow up to 15 feet, while females only grow to 10 feet. Look at the size of the snout and body. Females are narrower than males in both snout and body, but this is not a reliable indicator of gender.
Look at the location of the fully grown alligator. Female alligators build nests and lay on them. If you see young alligators around an adult alligator, it is most likely a female, since the males do not raise young.
Pick up a baby alligator less than a foot long and turn it upside down, making sure to hold the head away from your fingers. Gently angle the tail toward its belly and lightly press your fingers on either side of the "vent," the slit between the lower legs. A penis will emerge if it is a male and nothing will emerge in females, except perhaps a dot that is the clitoris.
Roll a larger alligator over onto its back and have one or two people hold it down. Place a few drops of oil onto a pair of small, blunt forceps. Gently insert the forceps into the vent and spread them a bit to see if a penis emerges. A clitoris will pop out in a female, but is much smaller than the male alligator's penis.