Giant bumblebees generally behave like their much smaller relatives, building underground nests and burrows. Workers collect nectar and pollen and build or repair the burrow while the queen creates a brood chamber where she lays her eggs. The queen lays her eggs over the entire summer months. In late summer and early autumn, the eggs hatch, forming new drones and queens. Both drones and queens leave the nest to mate with other bumblebees.

A giant bumblebee is about 8 feet long with a black body striped with yellow bands. Giant bumblebees are generally passive creatures. If threatened however, or if their nest is disturbed, they respond by stinging their opponents.