Emohawks are a form of polymorph whose natural form is something similar to a large bird or hawk. Like all polymorphs, the Emohawk is an emotional leech - it steals emotions from other living creatures. Its name is a portmanteau of "emotion" and "hawk."
Emohawks are domesticated variants of polymorph's that are spayed at birth, raised by the Kinitawowi and trained to do their bidding. Emotions drained by the Emohawks are a highly valued trading commodity amongst the Kinitawowi.
The Emohawk seems to be able to drain specific aspects of an individual's personality as well as mere emotions, and causes its victims to undergo physical changes in addition to mental ones; it drains Arnold Rimmer of his bitterness and Cat of his cool, turning them into Ace Rimmer and Duane Dibbley.