Spix’s Red-handed Howler

• Common Name: Spix’s Howler
• Taxonomy Classification Year: 1823
• Monkey Size: 40.0 to 91.5 cm (15.75 to 36.02 in)
• Skin Color(s): Yellowish-brown to reddish-brown
• Habitat: Forest, rainforest
• Diet: Herbivorous
• Native Countries: Brazil

Spix’s red-handed howler^[1] (Alouatta discolor) is a species of howler monkey endemic to the southeastern Amazon in Brazil.

• As the name suggests, Spix’s red-handed howler monkeys have hands (and feet) that lack the same inky black, reddish, or yellowish-brown fur that covers the rest of their bodies.
• They have a thick, prehensile tail, a patch of bare skin on the tip, coarse, shaggy hair, and a deep jaw surrounding an enlarged larynx and hyoid bone.
• All species of Alouatta have a schizodactylous or zygodactylous grip, which means that their first two digits are opposite the other three.

• The primary food sources of this species are ripe and unripe fruits. Of all the species in this genus, Spix’s red-handed howler is the most dependent on this food source.
• They typically travel in groups of 4 to 11 individuals and have relatively small home ranges of 5 to 45 ha.
• Spix’s Red-headed Howler is currently on the International Union for Conservation of Nature’s Endangered Species List based on a population decline of more than 30% over the last 3 generations, mainly due to habitat loss.
• The enlarged larynx and hyoid bone are highly specialized, helping them produce their infamous growls, howls, barks, and roars.
• Alouatta species are also the only New World Monkey genus to have full trichromatic vision, allowing them to perceive the world across the spectrum of visible light.