There is wide group of wild mammals as part of the great biological diversity of the ecosystems of the forests in the South of Mexico. Those which are more outstanding are three species of primates. Two of these three species are: the howling monkey (Aloutta palliate mexicana) - brown howling monkey-(Alouatta pigra) - black howling monkey. The specie A. palliata is present in most parts in the South of Mexico, mainly in the region of Los Tuxtlas (to the South of Veracruz). However, the black howling monkey is only found in the State of Tabasco (Northern part of Chiapas) and in the Peninsula of Yucatan. Another specie is the spider monkey which includes the sub specie A. geoffroyi vellerus whose original distribution comprehends from the South of Tamaulipas to Chiapas. In addition, the A. geoffroyi yucatanesis is restricted only to the Peninsula of Yucatan. The Mexican primates haven been directly affected by the disappearance or modification of their habitat. These species are in danger of extinction, which is why the illegal capture or sale of these animals is prohibited.