DEPTH PERCEPTION IN SHEEP: EFFECTS OF INTERRUPTING THE MOTHER-NEONATE BOND.

Twin lambs were divided into two groups: an unmothered group consisting of one of each pair of twins separated from its mother at birth, and a mothered group consisting of the other member of each pair reared by its mother. Lambs in both groups were placed individually on a "visual cliff" once every hour. In all instances lambs in the mothered group exhibited "cliff avoidance" behavior before those in the unmothered group. In another experiment, mothered lambs were fitted with translucent goggles for half the time required by unmothered lambs, matched on the basis of sex and birth weight, to acquire depth perception. Again, in all instances the mothered, goggled lambs avoided the cliff before the unmothered lambs.