A case study of infanticide after resident male replacement in Semnopithecus entellus around Jodhpur (India)

Abstract

During study period in October–November, 2009, an abrupt resident male replacement in a unimale bisexual troop of Hanuman langur (Semnopithecus entellus) at Arna (B-29), Jodhpur (India) has been documented. Having about 24 members including an adult male, 11 adult females and others (juveniles and infants of both the sexes) the resident male was there for about last two years. There were some 17–19 males in all-male band (AMB) nearby, used to approach the Arna troop occasionally. But the resident male of this troop was capable and potential enough to chase the males far away as and when they appeared in his troop’s territory. On October 4, 2009, two invading males approached the troop. However, the resident male tried his best to chase these invaders but was not successful and in one and half hours of violent fight, the bisexual troop’s resident male was cornered by outsider males. For whole day all invading males remained with the troop. The ousted resident male was not seen again after October 6. On October 7, 2009, one of those three invaders was observed as new resident male of Arna bisexual troop. Two cases of infant attacks were observed after male replacement in a free-living uni-male bisexual troop (B-29). The youngest infant, about three weeks of age was fatally wounded by an attack from the new resident male on October 9, 2009. The black coat infant, who was severely injured, died next day. A white coat infant, about six months old was also injured but survived. The new resident male became aggressive many times after these attacks and was seen running behind the female carrying the white coat infant. He looked normal troop leader on and from November 2009.