Throw another shrimp on the barbie – before it kills its friends

Hermaphroditic cleaner shrimp attack and kill each other when in groups larger than two, new research from the University of Tübingen has found.

The shrimp usually live in monogamous pairs in the wild. Living with a large group would mean sharing the available food between more shrimp.

When placed in groups of three or four in an aquarium, the shrimp attacked and killed the other shrimp during the night until only a single pair remained.