The house mouse (Mus musculus) is an opportunistic omnivore constantly seeking food and shelter, making it a common pest. When this behavior intersects with the cultivation or storage of Cannabis sativa L., the plant becomes a potential food source. Mice consume cannabis in various forms, driven by nutritional needs and the mechanical necessity of gnawing. This consumption introduces potent cannabinoids into the rodent’s system, triggering a distinct physiological response. Understanding the feeding behavior and the biological consequences of cannabinoid exposure is important for growers and consumers.
Do Mice Consume Cannabis Plant Material?
Mice and rats consume various parts of the cannabis plant, especially when preferred food sources are scarce. The attraction is strongest to cannabis seeds, which are rich in fats, proteins, and essential nutrients, offering a high-calorie reward. Rodents readily feast on freshly germinated seeds and young seedlings, often destroying new growth before it can establish itself.
Beyond the seeds, mice also consume leaf matter and dried flower material, though these are secondary choices. They inflict damage by chewing through stems and stalks, not always for consumption, but to wear down their continuously growing incisor teeth. This gnawing behavior can severely weaken or kill a mature plant by disrupting its vascular system.
The presence of mice is often indicated by chewed stems, scattered droppings, and damage to buds that have been shredded. This destructive behavior, which includes contamination of the product with urine and feces, poses a significant threat to both the yield and safety of a cannabis crop.
Biological Effects of Cannabinoids on Rodents
When a mouse consumes cannabis, active compounds like Delta-9-tetrahydrocannabinol (THC) interact with its native endocannabinoid system (ECS). Rodents possess a high concentration of cannabinoid receptor type 1 (CB1) receptors in the brain, similar to humans. This interaction results in a collection of four symptoms, referred to as the “tetrad effect.”
The tetrad effect is triggered by CB1 receptor activation and is a standard measure in laboratory studies to confirm cannabinoid agonist activity. It comprises four distinct physiological changes:
- Hypolocomotion (reduced movement)
- Hypothermia (a drop in body temperature)
- Catalepsy (a state of immobility)
- Analgesia (reduced sensitivity to pain)
The experience for the mouse is profound impairment and lethargy, effectively immobilizing the animal.
The raw cannabis plant contains cannabinoid acids, such as THCA, which are non-intoxicating. Psychoactive effects are primarily experienced after the material has been decarboxylated, typically through heating, which converts THCA to active THC. While acute cannabinoid ingestion is not considered acutely lethal for mice, it severely impairs their function, leaving them vulnerable to predators due to reduced body temperature and mobility.
Protecting Cannabis from Rodent Infestation
Preventing rodent access relies heavily on physical exclusion and sanitation. Growers and consumers should prioritize sealing all structural entry points, as mice can squeeze through openings as small as a quarter of an inch. Using materials like steel wool, hardware cloth, or cement to plug gaps is an effective first step.
The environment must be made unappealing by eliminating alternative food sources and nesting materials. This includes storing soil, seeds, or fertilizers in airtight containers and removing all debris, clutter, and standing water. Removing condensation or spills reduces the habitability of the space, as rodents require water for survival.
For both cultivation and storage, physical barriers are the most reliable defense. Mature plants can be protected by surrounding the base with fine-mesh hardware cloth. Harvested products should be stored in thick-walled glass jars or metal containers with secure, airtight lids.