Full Idea
What constitutes the essential difference between man and animal? The most simple, general, and most widely held answer to this question is consciousness. Consciousness is given only in the case of a being to whom his species ...is an object of thought.
Gist of Idea
Consciousness is said to distinguish man from animals - consciousness of his own species
Source
Ludwig Feuerbach (Introduction of 'Essence of Christianity' [1841], I)
Book Reference
Feuerbach,Ludwig: 'The Fiery Brook: Selected Writings', ed/tr. Hanfi,Zawar [Anchor 1972], p.96
A Reaction
Rather speculative. Since other species cohabit and breed only with their fellow species members, one might have thought they were aware of them.