Deer are opportunistic herbivores that frequently browse on garden plants and agricultural crops. For those growing plants with a strong scent, a natural question arises: does the unique aroma of the cannabis plant attract or repel these animals? Understanding deer olfaction and the plant’s natural defenses helps explain their observed behavior.
How Deer Process Scents
Deer possess a highly sensitive and complex olfactory system, which is paramount to their survival. Compared to humans, their larger olfactory bulbs and greater surface area of olfactory epithelium allow them to detect faint scent particles over long distances. This sophisticated sense is used for locating food sources, identifying predators, and communicating within their species.
Deer also utilize a specialized structure known as the vomeronasal organ (VNO), or Jacobson’s organ, located on the roof of their mouth. This organ analyzes non-volatile chemical signals, such as pheromones, often transferred through liquid contact like urine. When a deer curls its upper lip in the flehmen response, it is actively drawing these chemical signals into the VNO for analysis. The main olfactory system is connected to the part of the brain that controls immediate behavioral responses, while the VNO connects to the region controlling reproductive physiology.
The Unique Chemical Profile of Cannabis
The distinctive, potent odor of the cannabis plant is a product of complex biochemistry designed for defense. This aroma is primarily due to volatile organic compounds called terpenes. Terpenes are produced and stored in glandular structures on the plant’s surface called trichomes, serving as a chemical defense against various threats.
The plant uses these fragrant compounds to deter herbivores and insects from consuming its foliage. Sesquiterpenes found in cannabis, for instance, primarily deter grazing animals, including deer and rabbits. This defense is supplemented by cannabinoids, like THC and CBD, which are also stored in the trichomes. These cannabinoids act as secondary metabolites to repel pathogens and predatory animals, forming the plant’s evolutionary strategy to discourage being eaten.
Field Observations: Are Deer Attracted or Repelled?
Based on its strong chemical profile, the smell of mature cannabis generally functions as a deterrent to deer browsing. The high concentration of terpenes and cannabinoids creates an unpalatable taste and smell that deer typically avoid when other food options are available. This aversion is consistent with deer behavior around other highly aromatic plants, such as certain herbs or pine species.
However, the reality is more nuanced, as deer are opportunistic feeders whose choices are influenced by circumstance. While mature plants with fully developed, sticky, and resinous buds are often left alone, younger cannabis plants are more vulnerable. Young plants in the vegetative growth stage are softer, higher in moisture, and have not yet produced high concentrations of defensive terpenes and cannabinoids.
Anecdotal reports suggest that deer will readily consume the tender leaves and stems of young cannabis, treating them like any other appealing garden plant. When food sources are scarce, such as during winter or drought, a starving deer may ignore the deterrent odor and consume even mature foliage. While the characteristic smell is a strong biological signal of defense, it is not a guaranteed repellent against a hungry animal.