Editing Semnopithecus (section)

===Social structure===
[[File:Juvenile Indian Grey Langur.jpg|thumb|Juvenile gray langur]]
Gray langurs exist in three types of groups:
* one-male groups, comprising one adult male, several females and offspring;
* multiple-male groups, comprising males and females of all ages;
* all-male groups.<ref name="Rajpurohit 1992"/><ref name="Newton 1994"/>
All-male groups tend to be the smallest of the groups and can consist of adults, subadults, and juveniles. Some populations have only multiple-male groups as mixed sex groups, while others have only one-male groups as mixed sexed groups.<ref name="Rajpurohit 1992"/>

Some evidence suggests multiple-male groups are temporary and exist only after a takeover, and subsequently split into one-male and all-male groups.<ref name=r7/>

Social hierarchies exist for all group types.<ref name="Srivastava 1992"/><ref name="Rajpurohit 2005"/> In all-male groups, dominance is attained through aggression and mating success.<ref name="Rajpurohit 2008"/> With sexually mature females, rank is based on physical condition and age.<ref name="Koenig 2000"/><ref name="Borries 1991"/> The younger the female, the higher the rank. Dominance rituals are most common among high-ranking langurs.<ref name="Rajpurohit 2005"/> Most changes in social rank in males take place during changes in group members. An adult male may remain in a one-male group for 45 months.<ref name="Newton 1987"/> The rate of male replacement can occur quickly or slowly depending on the group.<ref name=r8/>

Females within a group are matrilineally related. Female memberships are also stable, but less so in larger groups.<ref name="Newton 1994"/><ref name="Koenig 2000"/> Relationships between the females tend to be friendly. They will do various activities with each together, such as foraging, traveling and resting. They will also groom each other regardless of their rank. However, higher-ranking females give out and receive grooming the most.<ref name=r9/> In addition, females groom males more often than the other way around.<ref name=r10/> Male and female relationships are usually positive. Relationships between males can range from peaceful to violent. While females remain in their natal groups, males will leave when they reach adulthood.<ref name="Newton 1994"/> Relationships between groups tend to be hostile. High-ranking males from different groups will display, vocalize, and fight among themselves.