Gorillas and grief: what the science says about primate mourning

In 2008, a three-year-old female gorilla named Ntare died at the Dian Fossey Gorilla Fund’s Karisoke Research Centre in Rwanda, and in the days that followed, members of her gorilla family — including adult males — were observed remaining close to her body, touching and interacting with her remains in ways that researchers carefully documented without using the word “grief” in their initial published accounts, because the science of non-human primate emotional states is governed by the same rigour that governs every other aspect of primate research, and claiming that a gorilla “grieves” requires evidence that goes beyond the behaviour of remaining near a dead group member. This evidence is now substantial enough to inform serious scientific debate, and it connects directly to what visitors observe on Bwindi gorilla treks — the social bonds that are visible during the encounter have depth that extends beyond what one hour can show. See Uganda safari packages.

In 2008, a three-year-old female gorilla named Ntare died at the Dian Fossey Gorilla Fund’s Karisoke Research Centre in Rwanda. For the next several days, members of her gorilla family — including adult males — were observed remaining close to her body, touching her, grooming her, and in some cases appearing reluctant to move away even as the group shifted location. Similar accounts have emerged from gorilla research stations across Central Africa over the decades, and comparable behaviours have been documented in chimpanzees, elephants, and other highly social mammals. The question that these observations raise — do gorillas grieve? — opens one of the more philosophically interesting areas of primate science.

What researchers have observed

The behaviours observed in gorillas and other great apes following the death of a group member include: remaining near the body for extended periods; touching, grooming, or carrying the body; apparent attempts to rouse the deceased individual; reduced activity and social engagement in surviving group members; and in some cases, mothers carrying dead infants for days or even weeks before finally abandoning them.

These behaviours are well-documented across multiple primate species. Chimpanzee mothers carrying dead infants have been observed at sites including Bossou in Guinea and Kibale Forest in Uganda — including in the habituated chimpanzee communities that researchers at the Kibale Chimpanzee Project have studied for decades. Elephant family groups have been repeatedly observed investigating and appearing to mourn the remains of deceased elephants, including those with which they had no direct relationship. Orca pods have been documented carrying dead calves for days.

The question is what these behaviours mean, and whether they constitute something analogous to human grief.

The challenge of interpretation

Attributing emotional states to non-human animals is methodologically challenging. Science properly requires evidence that can be observed, measured, and replicated — and the internal emotional experience of an animal, if it exists, is not directly accessible to any observer. What can be observed is behaviour, and the behaviours associated with primate responses to death are behaviourally consistent with what we would call grief in humans: prolonged proximity to the deceased, reduced social engagement, disrupted feeding, apparent distress.

Researchers who study this area have proposed a framework called “awareness of death” — the question of whether animals have a concept of death as a permanent state rather than simply responding to the absence or changed condition of a familiar individual. Gorillas and chimpanzees show evidence of some understanding: they do not treat a dead group member identically to an absent one, and the behaviours observed suggest recognition that something has changed irreversibly. Whether this constitutes awareness in the full philosophical sense — a conscious understanding of mortality — remains contested.

The study of animal cognition has shifted significantly over the past three decades. Where earlier generations of researchers were trained to avoid anthropomorphism rigorously — attributing human emotional concepts to animals was considered scientifically suspect — contemporary animal cognition research takes a more nuanced position. The question is not whether animals have human emotions, but whether they have functional analogues: emotional systems that evolved for similar adaptive reasons and that produce similar behavioural outputs. The evidence that great apes have functional analogues to human social emotions, including something analogous to grief, is now considered quite strong by most researchers in the field.

Physiological correlates

The behavioural evidence for primate grief is supported by physiological data. Cortisol — the primary stress hormone in mammals, including humans — is elevated in great apes following the death of close social partners, as measured through non-invasive analysis of faecal samples. Elevated cortisol is associated with psychological stress in humans and other mammals, and its elevation following social loss suggests that the experience of losing a group member involves genuine physiological stress responses consistent with what we would call emotional distress.

Oxytocin — a hormone associated with social bonding, attachment, and positive social interaction in mammals — is implicated in the stress response to social loss. In humans, grief involves the disruption of oxytocin-mediated bonding systems that evolved to maintain close social relationships. Evidence that the same systems operate in great apes suggests that the physiological infrastructure for grief-like responses is shared.

Gorillas and attachment

The strength of gorilla social bonds — particularly between mothers and offspring, between silverbacks and females, and between long-term group members — creates the conditions in which grief-like responses would be adaptive. In a species that lives in stable social groups for decades, whose members cooperate, support each other, and maintain long-term relationships, the loss of a significant individual represents a genuine disruption to the social fabric. Responses that help the surviving individual process that disruption — the behavioural equivalent of human mourning — would be advantageous.

Mountain gorilla research has documented individual gorillas whose behaviour changed measurably following the death of close social partners — reduced social activity, altered movement patterns, changes in feeding behaviour. These changes resolved over time, as they do in human grief, and survivors eventually resumed normal behavioural patterns. The trajectory — acute disruption followed by gradual recovery — mirrors the grief process in humans in ways that are hard to dismiss as coincidence.

Why this matters for conservation

The evidence for gorilla grief has practical conservation implications. If gorillas experience something analogous to grief, then the loss of group members — through poaching, disease, or human-wildlife conflict — has psychological consequences for survivors beyond the demographic effect. A group that loses its silverback does not simply lose a reproductive member; it loses the central relationship around which the group’s social structure is organised. The disruption this causes can lead to group dissolution, increased vulnerability to predation and disease, and reduced reproductive success in the years following the loss.

This understanding reinforces the case for treating individual gorillas as irreplaceable social beings rather than interchangeable population units. Conservation interventions — whether responding to snaring incidents, managing human-wildlife conflict, or making decisions about veterinary intervention — benefit from recognising the social and psychological consequences of individual deaths within gorilla groups. The gorillas’ capacity for grief is one more dimension of their complexity that makes their conservation both more urgent and more meaningful.