Bats are unique mammals known for their ability to fly. Like many animal species, they often gather in groups, and these gatherings have specific collective nouns that describe their social structures.
The Many Names for Bat Groups
The most recognized term for a group of bats is a “colony.” This refers to a large number of bats living together in a shared roost, like a cave or building. A colony can range from a few dozen to millions of individuals, depending on the species and available habitat.
When bats take to the sky in large numbers, particularly during their evening emergence from a roost, the collective noun “cloud” is often used. This term describes the dense, swirling mass of bats flying together. A “swarm” refers to a large, moving group, especially when they appear to move as a single entity in flight.
“Cauldron” describes a large or concentrated group, often seen circling an area like a lake. “Flock” is also used for bats flying together, particularly when hunting for food. The term “camp” has been used for bats roosting in large groups.
Why Bats Form Groups
Bats form groups for various biological and behavioral reasons, offering advantages for survival and reproduction. Roosting together provides sheltered environments for resting, mating, and rearing young, protecting them from harsh weather and predators. Many bat species are social, with group living influenced by roost availability.
Maternity colonies are temporary associations of reproductive female bats that gather to give birth and nurse their pups. These colonies offer thermal benefits, as huddling helps females maintain body temperature, reducing energy costs during gestation and lactation. This shared warmth is beneficial for developing pups, as they require extra heat. Communal roosting also provides safety in numbers for vulnerable young.
Group living also offers advantages for foraging and predator avoidance. While large groups might attract predators, the sheer number of individuals offers a diluted risk, making it harder for a single bat to be targeted. Foraging together, especially for species feeding on insect swarms, increases hunting efficiency through information transfer. Bats can eavesdrop on echolocation calls, helping them locate prey more effectively, especially when food sources are unpredictable. Additionally, bat colonies consume vast quantities of insects, benefiting ecosystems and agriculture.