A hoatzin. Photo by Carine06.

I was off the grid last week, so I missed Sarah Hird’s latest post at the group blog Nothing in Biology Makes Sense!, discussing a cool new study of the microbes in the guts of hoatzins, a species of wonderfully weird birds.

The hoatzin has an enlarged crop for the purpose of fermentation (see figure below). A “crop” is an anatomical structure in throat of some animals (including most birds) that primarily stores food. In the hoatzin, however, it does much, much more. Foregut fermentation is a digestive strategy where microbes living in or before the stomach break down vegetation for their host. Microbes are required by foregut fermenters because only the microbes are capable of breaking down the cell wall of plants, a barrier that confines most of the nutrients found in plant cells. The hoatzin is the only bird to use foregut fermentation and is the smallest known foregut fermenter.

To learn what the new study reveals about the diversity of microbes in hoatzin foreguts, go read the whole thing, including the evolving plans for follow-up experiments in the comments. ◼