Yes, cockroaches eat poop, and they don’t just do it out of desperation. Feces consumption, known as coprophagy, is a core survival behavior for cockroaches, especially in the early stages of life. Newborn cockroaches are actually hardwired to seek out feces almost immediately after hatching, and doing so shapes their gut health, social bonds, and development in ways that go far beyond simple nutrition.
Why Cockroaches Eat Feces on Purpose
Cockroaches are extreme omnivores. They’ll eat almost anything organic, from crumbs and grease to glue, paper, and yes, fecal matter from other animals and from their own species. But eating the feces of other cockroaches isn’t just opportunistic scavenging. It serves at least three distinct biological purposes: nutrition, gut microbe transfer, and social bonding.
Cockroach fecal pellets are concentrated nutrient packages. They contain leftover proteins, fats, and carbohydrates that still have nutritional value after passing through the digestive system. For tiny, newly hatched nymphs that can barely move around, the fecal pellets scattered around a cockroach shelter are essentially a ready-made food source containing everything they need to grow.
How Baby Cockroaches Use Feces to Survive
Newborn German cockroaches, the species most commonly found in homes, have low mobility and tend to stay put near where they hatched. While all life stages of cockroaches will eat feces, the behavior is most intense in the youngest nymphs. These tiny insects rely heavily on the fecal pellets left behind by older cockroaches in the group.
Beyond calories, those pellets deliver something critical: gut bacteria. Cockroach feces contain living bacterial cells, bacterial spores, and cysts from other microorganisms. When a newborn nymph eats these pellets, it seeds its own digestive tract with the microbial community it needs to properly break down food. Without this transfer, nymphs develop more slowly. Aggregating with a group of other cockroaches and eating their feces accelerates both physical development and reproductive maturation.
This is similar in concept to how some mammals acquire gut bacteria from their mothers, but cockroaches do it through feces rather than through milk or birth canal exposure.
Feces as a Social Glue
Cockroach feces contain chemical signals, specifically pheromones, that attract other cockroaches to group sheltering sites. Research from NC State University found that this attraction is innate. Newborn nymphs with no prior experience are drawn to the smell of cockroach feces from any group of the same species.
What happens next is more interesting. Once a nymph eats feces from its own colony, it develops a learned preference for the specific chemical signature of that group’s droppings. Nymphs that had eaten from their home colony’s feces preferred the smell of that colony over foreign groups. Nymphs that hadn’t eaten any feces yet showed no such preference, responding equally to fecal odors from all groups. In other words, eating poop is how baby cockroaches learn who their family is. It transforms a generic instinct into a specific social bond.
Cockroaches Also Recycle Their Own Waste Internally
Cockroaches have an unusual relationship with nitrogen, a building block of proteins. Most animals excrete nitrogen-containing waste and it’s gone for good. Cockroaches instead store their nitrogenous waste as uric acid in specialized cells within their fat tissue. They then partner with an internal bacterial symbiont called Blattabacterium, which lives inside dedicated cells in the cockroach’s body. This bacterium breaks down the stored uric acid and converts it back into amino acids the cockroach can use to build proteins.
This internal recycling system is one reason cockroaches can thrive on extremely low-quality diets. Combined with coprophagy, it means cockroaches extract value from waste at two levels: internally by recycling their own metabolic byproducts, and externally by consuming feces that still contain usable nutrients and microbes.
What This Means for Pest Control
The fact that cockroaches reliably eat each other’s feces has a direct practical application: it makes gel bait insecticides far more effective than they would otherwise be. When a foraging cockroach eats poisoned bait and returns to the group shelter, it defecates insecticide-laced feces. Other cockroaches, particularly the young nymphs that rarely leave the shelter, then eat those contaminated droppings and die too. This is called secondary kill.
Research published in the Journal of Economic Entomology found that slow-acting insecticides are especially effective through this route. A slow-acting poison gives the foraging cockroach enough time to return home and deposit contaminated feces before it dies. The insecticide remains stable as it passes through the digestive tract, so the fecal pellets retain a lethal dose. First-instar nymphs, the youngest and most shelter-bound, appear to be a particularly important link in this chain of transmission.
Cockroaches also engage in cannibalism and necrophagy (eating dead cockroaches), which provides additional pathways for poison to spread through a colony. But coprophagy is the most consistent mechanism because fecal pellets accumulate in shelters where the most vulnerable, hard-to-reach members of the population are concentrated.
Do They Eat Other Animals’ Feces Too?
Cockroaches are not picky about whose feces they consume. While the social and microbiome benefits are specific to eating feces from their own species, cockroaches will readily eat pet waste, bird droppings, rodent pellets, and human fecal matter when accessible. This is part of their broader dietary strategy of consuming virtually any organic material. In sewers, for instance, cockroaches have abundant access to human waste, and in homes, pet litter boxes and uncleaned animal areas can attract them. Any fecal matter represents a nutrient source to a cockroach, making sanitation one of the most effective deterrents against infestations.