At other times he classified them as many-legged, four-legged, two-legged or legless (Vin.II,110).
He said: ‘I know of no other class of things as diverse as the creatures of the animal world.’ (S.III,151; Sn.600).
Because animals have a limited capacity of comprehension and, thus, little chance to develop spiritually, and because the animal kingdom is dominated by the principle of ‘eat or be eaten,’ the Buddha considered it to be a distinct disadvantage to be reborn as an animal rather than as a human.
Nonetheless, he acknowledges that sometimes animals set an example that humans could do well to copy. Once when some monks were quarrelling with each other the Buddha said to them: ‘If animals can be courteous, deferential and polite towards each other, so should you be.’ (Vin.II,162).
The Buddhacarita says: ‘Empathy with all creatures is the true religion.’ (sarveṣu bhūteṣu dayā hi dharmaḥ). The earliest legislation to protect animals from cruelty and to provide reserves for wild animals was drawn up by the Buddhist monarch Aśoka in the 2nd century BCE. See Hunting.