Gorillas are intelligent and physically imposing primates inhabiting the dense, rain-soaked forests of central Africa. Despite their rugged appearance, they show a clear aversion to getting wet. Both mountain gorillas, who live in cold, high-altitude forests, and western lowland gorillas, who inhabit warmer rainforests, frequently experience heavy tropical downpours. Researchers observe that these massive apes prioritize staying dry, demonstrating complex behaviors and strategies to avoid the discomfort and biological costs associated with rain. Their immediate and deliberate actions to seek shelter confirm their dislike of rain.
Seeking Shelter During Downpours
The onset of a heavy downpour triggers an immediate shift in group behavior, replacing activities like foraging or resting with a rapid search for cover. Gorillas abruptly stop and move quickly toward established sheltered spots, often including dense thickets of vegetation or rock overhangs. The group adopts a stationary, hunched posture, remaining huddled and motionless until the precipitation ceases. This inactivity makes observing their normal routines difficult during rainy periods.
This reaction demonstrates a clear preference for dryness over continuing their daily schedule. The chosen shelter, such as thick foliage, minimizes the direct impact of rain and wind, helping to prevent the saturation of their thick fur. By remaining still, the gorillas also limit their body’s exposure and reduce the risk of becoming fully soaked.
Why Getting Wet is a Problem
The physical structure of a gorilla’s dense, black coat makes rain a biological challenge. Their fur is highly effective at trapping air, which provides a layer of insulation to regulate body temperature in both cooler montane environments and warmer lowlands. When this coat becomes fully saturated with water, the insulating air pockets are displaced, causing the fur to lose its thermal resistance.
The wet fur becomes heavy, making movement cumbersome, and takes an extended period to dry, leading to prolonged discomfort and heat loss. Even in tropical climates, rapid evaporation of water from their large surface area drains the gorilla’s body heat. To compensate, their metabolism must increase to generate more warmth, an unnecessary expenditure of energy they prefer to avoid.
Active Rain Management Strategies
Gorillas employ proactive strategies to manage moisture and maintain comfort, particularly when preparing for the night. They construct a new sleeping nest every evening, modifying the placement and composition to provide protection from rain and dampness. When rain is likely, they select nest sites beneath the thickest canopy cover or in locations that offer natural windbreaks.
The process of nest construction involves layering vegetation, which creates a dry, insulated barrier between the gorilla’s body and the cold, damp forest floor. This layered structure traps body heat during the night. This is an important thermoregulation strategy, especially for high-altitude mountain gorillas where nighttime temperatures drop. The strategic placement of these nightly resting platforms is their primary proactive defense against rain.
How Rain Disrupts Daily Activities
Rain impacts gorillas beyond physical discomfort, disrupting their daily schedule and foraging efficiency. Heavy rainfall can wash away scent markers gorillas use to locate specific food patches, making the search for their diverse diet more difficult. The resulting wet vegetation is also less palatable than dry forage, reducing their motivation to eat.
The physical environment becomes a hazard during and after a downpour. Trails become muddy and slippery, which makes movement across rugged terrain—especially the steep slopes inhabited by mountain gorillas—dangerous and energy-intensive. Sheltering forces gorillas into periods of inactivity, costing valuable time that would otherwise be spent foraging, traveling, and socializing. This reduction in foraging time translates into a direct energetic cost.