What are the black dots around an alligator’s mouth?

These conspicuous markings go by the catchy name of dermal pressure receptors (DPRs), and are miniature sense organs that the alligator uses to detect changes in water pressure caused by the movement of potential prey. DPRs are a feature of both crocodiles and alligators, but while the latter (and caimans) only have them around the mouth, crocodiles have them all over their bodies. We don’t know why, though this does make them a useful identification tool.