How and Why Horses Open Crescentia alata Fruits

Abstract

Costa Rican range horses break the hard, ripe fruits of Crescentia alata with their incisors and swallow the small seeds imbedded in the sugar-rich fruit pulp. The seeds survive the trip through the horse and germinate in large numbers where horses have defecated. The ripe fruits required about 200 kg pressure to break, and fruits that were too hard for the horses to break required 272 to 553 kg to break. Unbreakable fruits had thicker hulls, and their presence provides an example of how a fruit trait may serve to spread seeds among more than one kind of large dispersal agent.