Killer bee is a nickname for the Africanized honey bee. These bees simply behave like normal wild bees, as opposed to domestic bees, which were bred to be gentle. About fifty years ago, African honeybees were brought to Brazil, to boost that country’s honey production. But some of these aggressive bees escaped and started moving north. Africanized bees now live in parts of Texas, Arizona, New Mexico, Nevada, and southern California.
If you dive underwater to escape a swarm, the bees will not dive after you. What these bees will do, however, is hover above the water. When you come up for air, they may attack again. How do the bees know you’re down there? As you exhale underwater, bubbles rise to the surface, and the bees recognize the chemicals in your breath. That makes sense because the bees’ natural enemies are bears and skunks. When one of these animals attacks a hive, it goes snout-first. So bees have come to respond aggressively to the breath of mammals.
If you’re pursued by bees, pull your shirt over your head for protection and run as fast as you can to shelter. Like other bees, “killer bees” can sting only once. Their venom is no more toxic than that of “ordinary” bees.