Rabbits, both wild and domestic, are herbivores whose diet centers on plant matter, though they occasionally encounter fungi in their environment. Fungi range from microscopic molds and yeasts to macroscopic mushrooms and toadstools. While a rabbit’s digestive system is highly specialized for fibrous vegetation, consuming fungi is not a routine dietary practice, and its safety depends entirely on the specific species encountered.
The Standard Herbivorous Diet
A rabbit’s gastrointestinal tract is uniquely adapted to thrive on a high-fiber, low-nutrient diet, provided primarily by hay and grasses. Unlimited access to grass hay, such as Timothy or Orchard grass, is necessary to stimulate proper gut motility and prevent gastrointestinal stasis. This fibrous material is also essential for wearing down their continuously growing teeth, preventing painful dental disease.
Beyond hay, a rabbit’s daily intake should include a variety of fresh, leafy greens, such as romaine lettuce, dandelion greens, and cilantro. These greens provide necessary vitamins and moisture, supplementing the bulk fiber from hay. Commercial pellets offer a concentrated source of nutrients but should only be fed in limited quantities so the rabbit prioritizes the long-stem fiber found in hay.
Fungi as an Opportunistic Food Source
Wild rabbits do not naturally seek out fungi as a regular food source because their digestive systems are not optimized for this type of matter. Fungi, which are neither plants nor vegetables, lack the necessary cellulose and plant fibers found in their primary diet. Consumption is typically opportunistic, occurring when preferred grasses or vegetation are scarce, such as during drought or late autumn.
A rabbit may nibble on a mushroom or ingest fungal matter accidentally while grazing or digging, rather than actively foraging for it. Even non-toxic fungi, such as common store-bought varieties, are low in the long-strand fiber necessary for gut health and contain chitin, which rabbits cannot properly digest.
Understanding the Toxicity Risk
The greatest danger concerning fungi consumption for rabbits is the high risk of toxicity, which can be fatal. Wild mushrooms pose a significant threat because distinguishing between harmless and highly poisonous species is challenging, even for experts. Many toxic mushrooms, such as those in the Amanita genus, have no immediate warning taste, meaning a rabbit may ingest a lethal dose without refusal.
Mycotoxin Poisoning
Rabbits are also susceptible to poisoning from mycotoxins, which are toxic metabolites produced by molds like Aspergillus and Fusarium that contaminate hay, grains, and pellets. These mycotoxins, such as Aflatoxin B1 or Zearalenone, can cause chronic issues like poor growth and susceptibility to infections, or acute effects including liver and kidney failure.
Signs and Treatment
Signs of acute mushroom poisoning can include lethargy, diarrhea, reduced appetite, and neurological symptoms like tremors, seizures, or uncoordinated movement. If a pet rabbit is suspected of ingesting any wild fungus, contact an exotic veterinarian immediately. Collecting a sample of the ingested fungus for identification, if possible and safe, can greatly assist the veterinarian in providing appropriate treatment.