There are many species varying in size from 1/4 to 1 inch, with combinations of black, brown-orange, and yellow stripes and sections, robust bodies, and covered in hairs over most of the body. The hind legs are enlarged to form pollen baskets, and bumble bees often fly around with balls of yellowish pollen on their rear legs.

Bumble bees are social insects with colonies that include workers, queens, and males. Queen bumble bees overwinter in protected places, such as beneath logs, and begin to build nests in spring when weather is favorable. They may appear earlier than other insects because bumble bees can warm their bodies in cold weather, but they won't appear before flowering plants are available. Nests are built in cavities under or close to the ground, especially in old mouse burrows. Bumble bees will use structural cavities with entrances close to the ground. The nest is constructed with wax exuded from their bodies. Queens provide the developing eggs with a mixture of pollen and nectar, called "bee bread" As the young adult females emerge, they take over the work of foraging and caring for the nest and larvae. The queen then resorts to laying eggs.

Bumble bees cause minimal damage to structures. Their nests are constructed of waxy secretions from the body of the bee, similar to honeybee honeycombs. Problems arise when nesting material is left behind to be infested by wax moths or stored product beetles. These insects may then be- come a nuisance. The risk presented by bumble bees is stings from bees at the colony site or possibly from stepping on bees foraging in lawns. Bumble bees guard their colony aggressively, and each can sting many times. When encountered while foraging alone, bumble bees are gentle and unlikely to sting unless handled or stepped on.