Gorillas, like all mammals, require water to survive, yet they are rarely observed drinking from open sources like rivers or streams. Their unique physiology and herbivorous diet allow them to acquire nearly all necessary moisture internally. Direct water consumption is a rare event, an adaptation resulting from their foraging habits within dense forest habitats.
Hydration Sourced Directly from Food
The primary source of a gorilla’s hydration is the sheer volume and composition of the vegetation they consume daily. A full-grown male gorilla may eat up to 30 kilograms of plant matter daily, while females consume about 18 kilograms. This massive intake of succulent leaves, shoots, stems, and fruits doubles as their water supply due to the high moisture content.
Foliage, which forms the bulk of their diet, can have a water content ranging from 50.0% to 88.5%. Western lowland gorillas consume more fruit, which is naturally rich in liquid, providing a significant water boost. Gorillas also frequently ingest morning dew that collects on the broad leaves of the plants they eat. This combination provides sufficient fluid for their metabolic processes, reducing the need for external water sources.
The Behavior of Drinking Freestanding Water
Although rare, gorillas will actively seek out and consume freestanding water under specific circumstances. This behavior increases significantly when maximum daily temperatures are higher, suggesting a response to increased thermal stress and fluid loss. Drinking serves as a survival mechanism when the moisture content of their regular diet is temporarily insufficient.
When they do drink, gorillas employ methods to minimize contact with potentially contaminated ground water. They have been documented using a dipping-and-licking technique, where they dip their hand into the water and then lick the water from the hair on their knuckles or their cupped hand. Their natural method shows a careful approach to hydration, though tool use is documented in captive settings.
Environmental Factors and Species Variation
The hydration habits of gorillas are not uniform across the species, varying notably between high-altitude Mountain Gorillas and lowland subspecies. Mountain Gorillas inhabit colder, cloudier montane forests, where their diet is dominated by consistently water-rich foliage and stems. This dense, wet environment and folivorous diet contribute to their extremely low rate of drinking.
In contrast, Western Lowland Gorillas live in warmer, more humid environments, and their diet contains a higher proportion of fruit. Observations have shown that even within the Mountain Gorilla population, groups living in areas with less water-dense food sources, such as Bwindi, drink water more frequently than those in Virunga. These differences highlight how local vegetation composition and habitat temperature directly influence the need for external water consumption.