Do cows recognize people
by their faces?
P. Rybarczyk1, Y. Koba2,
J. Rushen1, H. Tanida2 and A.M. de Passille1
1Agriculture and Agri-Food
Canada, Lennoxville, Canada, 2Hiroshima University, Higashi-Hiroshima,
Japan
We used operant conditioning to examine whether cows recognize people by their faces. We trained 7 lactating cows with 2 people: a familar rewarder and an unfamiliar non-rewarder, who wore the same colour coveralls, but differed in height by at least 10cms. The two people stood within an operant chamber so they could be seen, smelt and touched by the cows. The cows received 75g of concentrate when they pushed a lever in front of the rewarder and nothing when they pushed a lever in front of the non-rewarder. The success criterion was at least 8 correct choices out of 10 in two consecutive sessions (p < 0.002). When both the rewarder and non-rewarder were standing at normal height and in full view of the cow, 5 out of 7 cows succeeded within 3 to14 sessions. When the people were seated behind a curtain so that only the head was visible, none of the cows succeeded. When both people were present fully visible except for their heads, which were completely covered by identical face masks, all cows succeeded. We then changed the relative height of the people. All cows succeeded when the faces of both people were covered but both people were standing at their normal height, and 5 out of 5 cows succeeded when the two people stood so they were of equal height but with their faces visible. However, no cows succeeded when the people were both of equal height and had their faces covered. Cows use multiple cues to discriminate between people, and can use either the faces or a difference in height. Cows cannot use the face alone if the rest of the body is not visible. Operant conditioning is an effective way of examining cows abilities to recognize people.