When an Africanized honeybee hive is disturbed, the entire colony of bees may swarm out to attack the intruder, and they may pursue up to 500 yards away from the hive before returning. This behavior is in direct contrast to the behavior of European honeybees, which typically send out less than 10 percent of the hive and quickly break off pursuit once the threat leaves the area.
While media reports often make it seem like killer bee attacks are unprovoked, the vast majority of them occur due to a perceived threat to the hive or the colony's territory. Africanized bees are much more defensive than other types of bees, reacting aggressively to even the most minor provocation. The sheer number of bees involved in the attack presents the greatest danger, as repeated stings can inject enough venom to seriously injure or kill people and other animals. Killer bee attacks kill an average of one or two people each year.
While Africanized bees have been able to supplant their European cousins in the southwestern United States, some beekeepers have discovered colonies of killer bees that lack their usual aggressive nature. Careful management and breeding may reduce the threat from these aggressive bees, making them a more useful species to humans.