Before the first strike: what social animals do in the hours ahead of a fight

On a stretch of East African savanna, an hour before two clans of chimpanzees meet at a contested boundary, the larger party goes quiet. Foraging tap-foraging slows. Individuals drift into view of one another and hold it. A few break toward the frontier to probe. The rest remain behind, closer together than usual, grooming each other with an intensity that has nothing to do with hygiene. None of the violence that the primatology literature records has begun. All of it has been prepared.

That sequence, pulled apart and re-stitched across species, is the subject of a review published this week that argues social animals run a recognisable pre-conflict playbook. The authors catalogue what they call preemptive behaviours: quieting the group, increased vigilance, raiding parties, tighter bonding through play and grooming, and shifts in who stands where in the formation. The argument is not that war is instinct in any simple sense. It is that, before the first strike, the diplomatic and tactical groundwork for a strike is already done, and it looks remarkably similar whether the animal is a chimpanzee, a banded mongoose, a paper wasp, or a human patrol.

The quiet before

The review's first move is to draw attention to silence. Across the taxa surveyed, a drop in vocalisation precedes confrontation. Chimpanzee communities fall quiet in the hours before a border patrol. Banded mongoose groups reduce sentinel calls. Even in colonies of social insects, foraging traffic reorganises into tighter lanes before raids on rival nests.

The functional reading is straightforward. Noise carries. A group that wants to manoeuvre without tipping its hand will sound less. The authors note the same dynamic in human military doctrine: pre-operation radio silence, blackout periods, dispersal of formations. They argue against treating these as a quirky analogy. Quieting is a convergent solution to the same problem, and it appears in the ethogram with the same regularity as the fight itself.

Vigilance and the raid

If the first half of the playbook is concealment, the second is reconnaissance. Vigilance rises; sentinel behaviour intensifies; parties thin out into small probing units that test the boundary. In chimpanzees, these are the border patrols that the literature has documented since the 1970s. In banded mongooses, they take the form of smaller "dispersal groups" that approach neighbouring packs. In social wasps, they are scouting flights that return with chemical cues from competitor nests.

The review treats raids as preemptive rather than offensive: their purpose, the authors argue, is to gather information about numbers, location and disposition before any wider engagement. That distinction matters. It reframes raiding from aggression to intelligence, and lines up with what field observers already describe, that the patrol is rarely the fight, but it almost always determines the shape of the fight that follows.

Bonding under threat

The least intuitive item in the catalogue is the third: increased affiliative behaviour, including play, grooming, and huddling. The review treats this as load-bearing. Affiliation reduces within-group variance. It synchronises arousal. It broadcasts, both to insiders and to rivals watching, that the group is coherent and unlikely to fragment under pressure.

In chimpanzees, grooming rates spike in the run-up to inter-community encounters; in banded mongooses, the same holds for allogrooming sessions and play-fighting. The authors are careful to distinguish this from reconciliation. Reconciliation happens after conflict. Affiliation before conflict is forward-looking. It is the social equivalent of a rally, and it plays the same structural role as a rally.

What the synthesis does, and what it does not

The value of the review is its refusal to treat the literature on war as a human monopoly. By tabulating the same five or six behaviours across primates, carnivores, insects and historical human cases, it makes a quantitative case that there is a shared pre-conflict grammar. That grammar is useful for field biologists because it tells them where to look for telltales in species not yet studied for this question. It is useful for evolutionary anthropology because it sharpens the comparative claim: humans are not exempt from the pattern, only elaborate versions of it, with the additions of language, planning and institutional command.

The limits are worth marking. The review relies on existing field studies, which are uneven across taxa and biased toward species that have been observed over long timescales. It cannot resolve a long-running debate about whether preemptive behaviour is best read as evolved adaptation, by-product of generalised stress responses, or culturally transmitted within populations that have seen enough conflict to recognise its shape. The authors gesture at all three without committing.

A second caveat: the review treats human cases at a high level of abstraction and does not adjudicate between competing accounts of why human groups go to war. Anyone looking for a glib bridge from chimpanzee patrol behaviour to contemporary geopolitics will not find one in the paper, and the authors are explicit that they are not trying to build one. What they offer instead is a vocabulary, and the case that the vocabulary travels.

The implication, soberly stated, is that the diplomatic, intelligence and morale work that precedes organised violence is not a human invention added on top of a base aggression. It is the baseline. Recognising it in other species gives biologists new ways to study conflict; recognising it in ourselves makes the work that armies and movements do before a fight less mysterious, and less easy to mistake for the cause of the fight rather than its prelude.

Desk note: Monexus framed this as a behavioural-biology story rather than a policy or geopolitics piece. The review covers human cases briefly and explicitly disclaims bridges to current events; the piece above honours that boundary.