The list features nine primate species from Asia, six from Madagascar, five from Africa and five from the Neotropics. In terms of individual countries, Madagascar tops the list with six of the 25 most endangered species.
Vietnam has five, Indonesia three, Brazil two, and China, Colombia, Côte d'Ivoire, the Democratic Republic of Congo, Ecuador, Equatorial Guinea, Ghana, Kenya, Peru, Sri Lanka, Tanzania and Venezuela each have one.
The San Martin titi monkey from Peru (Callicebus oenanthe) exists now in extremely fragmented, small groups. Its estimated decline is 80 percent over the last 25 years.