If a female sifaka inherits a different form of the gene on each of its X chromosomes — as in humans, only females have two X chromosomes — its eyes are endowed with all three cones, in a phenomenon called «polymorphic trichromacy.» (nautil.us)
There are nine recognized species of sifakas in Madagascar, and all have similar social structure with only two reproducing adults and between two and four members. (sciencedaily.com)
The golden crowned sifaka, Propithecus tattersalli, is a lemur living in small social units in the north of Madagascar. (sciencedaily.com)