[4] The species has been observed on the left bank of the Guayabero River,[5], where it was collected in 1959 by Jorge Hernández Camacho, both in La Macarena National Park, and recently it was observed by the Colombian biologist Rocío Palanco north of the Guayabero above La Cordillera de los Picachos National Park.
[6][7] This error is due to the collection of a specimen by the English ornithologist Cherrie in about 1904 from Maipures, which may have been a captive animal obtained in the village, since extensive and concerted efforts have failed to identify it for the entire area mentioned above;[original research?]
[11][12] Easley calculated a time budget based on 400 hours of observation as 62.7% rest, 16.5% moving, 16.1% feeding, 2.7% grooming, 1.6% playing and 0.3% vocalizing.
[13] Palacios & Rodríguez calculated 54.3% rest, 22.9% moving, 17.6% feeding, 4.07% grooming, 0.41% playing, and 0.42% vocalizing based on 240 hours of observation.
[11] Easley analyzed the locomotive and positional behavior of the species showing that it is a generalized quadruped using quadrupedal walking and running about 66.8% of the time.
[14] Groups of collared titis sleep on top of large branches of emergent trees, frequently a bit above the level of the main canopy.
Lepidopteran larva, spiders and orthopterans are especially eaten with relish and probably occasional small lizards, judging by the hunting preferences of a tame, free-ranging adult female, which lived at the Caparú Biological Research Station on the lower Apaporis River.
[8] Kinzey found the following range of dietary preference during his 135 hours study in Peru: 14% Clarisia racemosa (Moraceae); 13% unidentified (Guttifereae); 7% Pithecellobium sp.
(Convolvulaceae); Jessenia bataua (Arecaceae); Psychotrian axillaris (Rubiaceae); Guatteria elata (Annonaceae); Virola sp.
[16] Easley identified frequency of item choice in the diet of the same groups as above: 74.1% fruits, 15.8% insects, 8.8% leaves, 0.6% buds and flowers and 0.1% other.
The preference values of each family, according to species utilized is as follow: Myristicaceae (25.02%); Euphorbiaceae (15.28%); Moraceae (14.37%); Arecaceae (8.68%); Caesalpiniaceae (7.85%) Rubiaceae (5.10%); Chrysobalanaceae (4.41%); Annonaceae (4.19%); Cecropiaceae (4.03%); Araceae (1.95%); Elaeocarpaceae (1.78%); Dilleniaceae (1.69%), Combretaceae (1.17%), Apocynaceae (1%); Aquifoliaceae (1%), Meliaceae (0.88%); Sapotaceae (0.85%); Burseraceae (0.81%); Apocynaceae (0.67%); Monimiaceae (0.23%); Piperaceae (0.22%); Melastomaceae (0.18%); Humiriaceae (0.13%) Celastracezae (0.11%); Myrtaceae (0.09%); Lecythidaceae (0.08%); Aquifoliaceae (0.07%); Sterculiaceae (0.07%); Solanaceae (0.05%); Clusiaceae (0.02%).
During the period of receptivity (which lasts 2–3 days) the black labia and the clitoris became swollen and hard and behavior changes occurred.
During the receptive period the female became much more affectionate towards its human "parents", purred loudly, somewhat like a cat and crouched in a lordotic position when the base of the tail was stimulated.
A close analysis of the diet of the black titi here would be interesting, inasmuch as it would serve to identify the resources which allow the species to have this birth pattern.
However, we know that fleshy fruits are beginning to increase from their yearly low during this time, so the question of resource use by the species remains very interesting.
[8] There is some evidence that titis not only can determine sex from a long call but can identify duetting individuals, so it should perhaps not be surprising that a resident pair could distinguish a recording from a live monkey and move away from it.
The only exception to this was one male which attempted to establish a relationship during two years before giving up and leaving during an accidental 26-day absence of the female when she became inadvertently lost in the forest.
A margay was detected alongside a dead black titi during recent censuses on the Purité River in Colombia, although the monkey was not freshly killed.