Rio Mayo titi in deforestation is leading to the decrease in available living space for this titi monkey, forcing it to live in sympatry with another species of "Callicebus". Yet in some areas, such drastic deforestation has resulted in extremely high population density. The Rio Mayo titi is better adapted to moderately populated areas, thus overpopulation negatively impacts the species. The forests the Rio Mayo titi lives in are being destroyed for agricultural purposes, leaving little forest for the monkeys. They were only seen a few times and featured in museums until 2003 when more research was done on them. In order for
Collared titi least two species in this complex. But whether the Lucifer titi, "Cheracebus lucifer", or the Colombian black-handed titi, "Cheracebus medemi", are good species from this complex is in doubt. They are probably subspecies of "Cheracebus torquatus". Nevertheless, in this treatment "C. torquatus" is used in the sense of Hershkovitz (1990) until the systematics of this species complex becomes clearer. Five adults weighed an average of 1462 g (range 1410–1722 g) with a head-body length of around 290–390 mm and a tail length of about 350–400 mm. The face has very little hair, being limited to sparse short white hairs over