| Scientific name | Leontocebus nigrifrons* |
| Head-body length | 20-23 cm |
| Tail length | 30-35 cm |
| Body mass | 300-400 g |
| Distribution | western Amazonia (south of Rio Amazonas between Rio Ucayali and Rio Yavarí) |
| Habitat | lowland tropical rainforest of terra firme type |
| Diet | fruits, exudates, nectar, arthropods, small vertebrates |
| Social organization | groups of 3-9 individuals (1-3 adult males, 1-2 adult females) |
| Mating system | polyandry (a single reproductive female mates with two or more adult males of her group) and monogamy |
| Reproduction and infant care gestation | 145-155 days; generally dizygotic twins; adult and subadult group members carry the infants and share food with them |
| Social behavior | allogrooming and resting in body contact are the most frequent affiliative behaviors; aggression is rare |
| Communication | scent marking with anogenital, suprapubic and rareley sternal glands; conspicuous “loud calls“, predator-specific alarm calls |
| Home-range size | 25-45 ha |
| Interspecific relations | stable associations with Saguinus mystax |
| Predators | confirmed at EBQB: eagles, snakes; suspected: tayra, cats, capuchin monkeys |
