Guatemalan Black Howler - Sympatry

Sympatry

The Guatemalan black howler is sympatric with the mantled howler along the edges of its range in Mexico and Guatemala near the Yucatan Peninsula. One theory for how this sympatry occurred and why the Guatemalan black howler has such a restricted range is the ancestors of the Guatemalan black howler and the Central American squirrel monkey migrated to Central America from South America during the late Miocene or Pliocene. However, passage through the Isthmus of Panama then closed for a period due to rising sea levels, and later opened up to another wave of migration about two million years ago. These later migrants, ancestors to modern populations of white-headed capuchins, mantled howlers and Geoffroy's spider monkeys, out-competed the earlier migrants, leading to the restricted range of the Guatemalan black howler (and the Central American squirrel monkey).