Why do gorillas eat their poop

Overview

Coprophagy, the consumption of feces, is observed in various animal species including gorillas, though it's often misunderstood as abnormal behavior. In gorillas, this practice has been documented since at least the 1970s in both wild and captive populations, with scientific studies increasing in the 1990s as researchers sought to understand its nutritional significance. Gorillas are primarily herbivorous, consuming up to 40 pounds of vegetation daily, including leaves, stems, and bark that are difficult to digest. Their natural diet in Central African forests consists of over 200 plant species, but captive gorillas often have less varied diets, which may contribute to increased coprophagy. Historical observations show that while wild mountain gorillas occasionally practice coprophagy, it's more prevalent in zoo environments where dietary options are limited. The behavior occurs across all gorilla subspecies, including Western lowland gorillas and Eastern mountain gorillas, suggesting it's an adaptive trait rather than pathology.

How It Works

Gorillas practice coprophagy through a specific process that maximizes nutritional benefits. When gorillas initially digest their high-fiber plant diet, only about 60-70% of nutrients are extracted during the first pass through their digestive system. By consuming their own or others' feces (particularly fresh feces), they reintroduce partially digested material containing undigested plant fibers, vitamins, and gut bacteria back into their system. The gorilla's digestive tract then has a second opportunity to break down cellulose and hemicellulose through microbial fermentation in their enlarged cecum and colon. This process allows them to extract additional B vitamins (especially B12 and folate) that are produced by gut bacteria during fermentation. The behavior typically involves consuming feces within minutes of defecation when nutrient content is highest, and gorillas may preferentially consume feces from individuals with healthier gut microbiota. Young gorillas learn this behavior through observation and may consume maternal feces to inoculate their own digestive systems with essential microorganisms.

Why It Matters

Understanding gorilla coprophagy has significant implications for conservation and captive management. For zoo professionals, recognizing this as natural behavior rather than pathology helps improve gorilla welfare through better dietary planning that reduces excessive coprophagy while maintaining nutritional balance. In conservation biology, studying coprophagy provides insights into gorilla digestive adaptations that enable survival on low-quality vegetation, which is crucial as habitat loss forces gorillas into marginal areas with poorer food resources. The behavior also highlights the importance of gut microbiota in primate health, with applications for understanding human digestive disorders and the role of probiotics. Additionally, public education about coprophagy helps combat misconceptions about gorilla behavior, promoting more accurate understanding of these endangered primates and supporting conservation efforts for the approximately 1,000 mountain gorillas and 100,000 western lowland gorillas remaining in the wild.