Bats have a few collective nouns associated with them. The main collective nouns for Bats are a colony, a cloud or cauldron. Other collective nouns for Bats include a hanger. The etymology of the collective nouns for Bats is related to their behavior. A colony of Bats refers to the large groups of Bats that roost together in caves or other dark places. A cloud of Bats is a reference to the large numbers of Bats that can be seen flying together in the sky. A cauldron of Bats is a reference to the swirling motion of Bats flying in a circle.