Contents

15 September 1989
Vol 245, Issue 4923

About The Cover

The hoatzin, Opisthocomus hoazin, a neotropical leaf-eating bird, is the only bird known to have ruminant-like foregut fermentation. This unexpected digestive system in a small flying endotherm provides new insights into theoretical size limitations in vertebrate herbivores and the evolution of foregut fermentation as a digestive strategy. See page 1236. [Photograph by Stuart D. Strahl, WCI—New York Zoological Society]