Articles | Volume 1, issue 1
https://doi.org/10.5194/pb-1-23-2014
https://doi.org/10.5194/pb-1-23-2014
Short communication
 | 
28 Oct 2014
Short communication |  | 28 Oct 2014

Do wild titi monkeys show empathy?

A. Clyvia, M. C. Kaizer, R. V. Santos, R. J. Young, and C. Cäsar

Abstract. We observed a putative case of empathy among wild black-fronted titi monkeys (Callicebus nigrifrons) from two different groups (D and R). In over 10 years of behavioural observations of five habituated groups of this species, only low levels of inter-group tolerance have been observed. However, on one day, we encountered the adult male from group D limping (poor hind limb motor coordination) as he travelled alone along the ground. Interestingly, we observed that members of group R did not express any agonistic behaviour towards this neighbouring male and apparently allowed this disabled individual to follow them in the forest for over 5 h. They stayed low in the forest (< 2 m above the ground) and < 10 m horizontally from the individual, and remained in visual contact with him. At the end of the day, this male from group D slept in the sleeping site of group R and was groomed by the adult female of group R. Such tolerance between members of different groups has never been previously observed in this species. Furthermore, group R exposed themselves to increased predation risk by staying close to the ground for protracted periods. The behaviour of group R could be interpreted by as a putative case of empathic responding in this species.

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Short summary
We report the first case of putative empathic response in titi monkeys (Callibebus). Pair bonds between males and females are typically strong, with substantial time spent grooming and tail twining. In an intriguing and unexpected observation we recorded an injured adult out-group male travelling with a neighbouring group. The group appeared to adapt travel patterns to allow him to accompany them, provided pro-social behaviour such as grooming and tolerated his presence at their sleeping site