Hork-Bajir

The Hork-Bajir are a sapient species known to be one of those to be capable of infection from the Yeerks. Despite their appearance, they are herbivorous, and eat the bark off trees. They are a peaceful species, and until infested by the Yeerks, did not understand the concept of fighting. They were created by the Arn, another species, to look after the trees on their homeworld, because the atmosphere on the planet was unstable, and if it was even slightly changed, the Arn could die out.