One poorly understood element of cat hunting behavior is the presentation of prey to human guardians. Ethologist Paul Leyhausen proposed that cats adopt humans into their social group, and share excess kill with others in the group according to the local pecking order, in which humans are placed at or near the top. Anthropologist and zoologist Desmond Morris, in his 1986 book Catwatching, suggests that when cats bring home mice or birds, they are attempting to teach their human to hunt, or trying to help their human as if feeding "an elderly cat, or an inept kitten". Morris's theory is inconsistent with the fact that male cats also bring home prey, despite males having no involvement with raising kittens.