White-eared titi the males. There is a strong bond between the adult mating pair, they stay close and carry out activities together. Either member of the pair may follow the other and leadership changes through the day. Evidence of the strength of the pair bond is shown by grooming, huddling together with their tails twined, nuzzling, and gentle grasping. Titi monkeys are highly territorial and when confronted with another family group, both will respond with threatening behaviour, males showing increased agitation towards intruding males. When not close together, the pair show a significant amount of distress and agitation. Titi monkeys are well
White-eared titi species within the genus "Plecturocebus". Although the exact position of species within the genus "Plecturocebus" in the "P. donacophilus" group with the Rio Beni titi ("P. modestus"), Rio Mayo titi ("P. oenanthe"), Ollala brothers' titi ("P. olallae"), and white-coated titi ("P. pallescens"). The white-coated titi has sometimes been considered a subspecies of the white-eared titi, but they are treated as separate species in the latest edition of Mammal Species of the World. The white-eared titi is a medium-sized primate with grey to orange pelage. The species does not exhibit sexual dimorphism; the male's head and body length averages while females