They are the first offshoot in the Callitrichidae tree, and therefore are the sister group of a clade formed by the lion tamarins, Goeldi's monkeys and marmosets.

[3] Hershkovitz (1977) recognised ten species in the genus Saguinus, further divided into 33 morphotypes based on facial pelage.

[5] A taxonomic review (Rylands et al., 2016) showed the tamarins are a sister group to all other callitrichids, branching off 15–13 million years ago.

The review noted that the smaller-bodied nigricollis group began diverging 11–8 million years ago, leading the authors to move them to a separate genus, Leontocebus (saddle-back tamarins).

[9] Following the taxonomic review of tamarins by Rylands et al. (2016) and Garbino & Martins-Junior (2018), there are 22 species in the genus Saguinus with 19 subspecies.

Tamarins are omnivores, eating fruits and other plant parts as well as spiders, insects, small vertebrates and bird eggs.

[6] Saddle-back tamarins have longer and narrower hands than Sanguinus species, possibly adaption to differing foraging behavior, as saddle-back tamarins are more likely to search for insects that are hidden in knotholes, crevices, bromeliad tanks and leaf litter, while Sanguinus species are more likely to forage for insects that are exposed on surfaces such as leaves or branches.

Due to their small size compared to other primates, they are an easy target for predatory birds, snakes, and mammals.