Maturation and development of social behaviour during early ontogeny in free-ranging dog puppies in West Bengal, India

Six bitches and their offspring were observed in the natural environment to study the early ontogeny of certain processes like eye opening, nipple preference, play, sexual activities and locomotion. Thirteen puppies out of 35 survived at the age of 3 months indicating 63% mortality. Eye slits were observed on day 12 (median) of life, and the eyes completely opened on 17 day (median) of life. The rearmost (fourth) nipple pair presumably containing more milk was suckled preferably by the puppies showing no sex bias. Social communication among the littermates was developed through playful interactions. Play behaviour developed in three subsequent stages—social play, agonistic play, and pseudo-sexual activity; at 3, 5 and 6 weeks, respectively. Playful interactions increased with the age of the puppies to establish a stable social hierarchy, and suddenly decreased between 8 and 10 weeks of life. Aggressive play tended to be initiated by males and specific individuals within a litter, suggesting individual variation in aggressiveness. Development of pseudo-sexual behaviour especially in male puppies by week 6 was an interesting feature of this study. The puppies were mobile at the age of week 3 when the eyes completely opened, and they were highly mobile when the suckling bouts disappeared and they traveled independently for food collection (10–11 weeks of life).