Preference for meat is not innate in dogs

Indian free-ranging dogs live in a carbohydraterich environment as scavengers in and around human settlements. They rarely hunt and consequently do not encounter rich sources of protein. Instead, they have adapted to a diet of primarily carbohydrates. As descendents of the exclusively carnivorous wolves, they are subjected to the evolutionary load of a physiological demand for proteins. To meet their protein needs, they resort to a Rule of Thumb-if it smells like meat, eat it. Pups face high competition from group and non-group members and are in a phase of rapid growth with high protein demands. Following the Rule of Thumb, they can acquire more protein at the cost of increased competition and reduced supplementary non-protein nutrition. However, if the mother supplements their diet with protein-rich regurgitates and/or milk, then the pups can benefit by being generalists. Using a choice test in the field, we show that, while adults have a clear preference for meat, pups have no such preference, and they even eagerly eat degraded protein. Thus, the Rule of Thumb used by adult dogs for efficient scavenging is not innate and needs to be learned. The Rule of Thumb might be acquired by cultural transmission, through exposure to meat in the mother's regurgitate, or while accompanying her on foraging trips.