Cecotrope

Cecotropes (also caecotropes, cecotrophs, caecotrophs, cecal pellets, soft feces, or night feces) are nutrient-filled packages created in the gastrointestinal (GI) tract that are expelled and eaten by many animals (such as rabbits, guinea pigs, mice, hamsters, and chinchillas) to obtain more nutrients from their food. Cecotropes are distinct from feces, which are composed primarily of indigestible components.

When food passes through the GI tract the first time, the stomach and the small intestine digest the food material, absorbing simple sugars, fats, and amino acids. As the undigested material moves into the colon, the food particles are sorted by size. The smaller particles of fiber are moved into the cecum where they are fermented by microbes. This creates nutrients which are generally not absorbed well in the colon, but are stored and expelled in cecotropes, including short-chain fatty acids, vitamin B, sodium, potassium, and amino acids. The nutrients from the ingested cecotropes are absorbed in the small intestine.

Lagomorphs (a group including rabbits, hares, and pikas) are perhaps the most well-known for producing and eating cecotropes, but other monogastric fermenters, such as rodents, also produce cecotropes. Rodents including beavers, guinea pigs, mice, hamsters, and chinchillas are known cecotrophs. Other animals also eat cecotropes, such as the common ringtail possum and the coppery ringtail possum.

The act of eating cecotropes is referred to as cecotrophy, which is distinct from coprophagy, which is the eating of feces proper. Similarly, cecotropes are not fecal material, so terms such as "soft feces" and "night feces" are technically incorrect. Though cecotropes are sometimes called "night feces," they are produced throughout the day and night.