A group of penguins is called a colony or a rookery. These terms are used to describe a large gathering of penguins, especially when they are nesting or breeding. In the water, a group of penguins is often referred to as a raft.
Penguins are social birds and often live in large groups to protect themselves from predators and to keep warm in cold climates. The size of the group can vary depending on the species and the environment. For example, Emperor Penguins form massive colonies during the breeding season, which can consist of thousands of individuals.
Understanding these terms helps in appreciating the social behavior and survival strategies of penguins in their natural habitats.