Science1 publisherNot yet confirmed elsewhere2 min readPublished
Across 100 primate species, lethal violence evolved separately from routine fighting
University of Lincoln researchers comparing 100 primate species found that lethal violence evolved largely apart from everyday aggression. A species' rate of routine fighting is therefore a poor guide to how often it kills rivals or infants.
The Scientist · Science desk
What happened
- The Lincoln team compared five forms of aggression, from ordinary conflicts to lethal attacks, using a large dataset spanning the primate species.
- The different lethal behaviours, such as killing adult rivals and infanticide, were moderately associated with one another across species.
- The study, by Bonaventura Majolo, Samantha Wakes and Marcello Ruta, appears in the journal Evolution Letters.
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Why it matters
- constraint If the decoupling holds, ranking species by general aggressiveness says little about the behaviour with the highest stakes: killing rivals and infants.
- decision Researchers who use rates of routine fighting as a proxy for lethal risk in a primate species would need direct records of killings and infanticide instead.
- precedent Because lethal behaviours cluster with one another, studies of the origins of violence can treat killing as its own trait class and search for the pressures that drive it.
The theory under test makes a clean prediction. If aggression is one broad trait, as many accounts of the origins of violence assume, then species that fight often should also kill often [5]. Bonaventura Majolo's group at Lincoln [4] compared five forms of aggression, from ordinary conflicts to lethal attacks, in a dataset covering 100 primate species, humans among them [1][6]. Then they looked at which forms tend to occur together.
Lethal behaviours clustered. The different kinds of killing, including attacks on adult rivals and infanticide, were moderately associated with one another [7][9]. Mild aggression showed little connection to that cluster [8]. The paper's title calls the result an "evolutionary decoupling between mild and lethal conspecific aggression" [3].
I like the design. The single-spectrum idea is a claim about how traits evolved, and a comparison across many species tests it at that scale.
"Moderate" and "little" are the release's words. It does not report correlation coefficients, how many of the 100 species had data for all five measures, or how the analysis handled the fact that closely related species share behaviour by descent.
A pattern across species shows only what varies together, so the cause is still an open question. The authors read the split as a sign that lethal violence and everyday conflict have distinct biological and evolutionary mechanisms [13]. The release goes a step further, saying different types of aggression "may arise under different social and evolutionary pressures" [10].
Humans are in the dataset [1], and the release places the work in a long debate in anthropology and evolutionary biology over whether violence is rooted mainly in deep evolutionary history or shaped more by social and cultural forces [12]. The comparison does not settle that debate. It removes one argument: the inference that a species which fights a lot must also be prone to killing. Majolo's own conclusion stays at that level, and I think it is the defensible one.
"Our study shows that the evolution of aggression follows more complex patterns than what earlier models proposed, that it is biologically inaccurate to rank species on the basis of their general propensity for aggression and that we need a more nuanced approach when discussing whether humans are inherently violent," Majolo said [11].
What to watch
- Independent primate datasets, compiled by other groups, testing whether mild aggression again shows little link to killing.
- Studies naming which social or ecological conditions predict lethal aggression across species, the pressures the release says may differ from those behind everyday conflict.
- Where humans fall on the lethal measures in the comparison: inside the primate cluster or apart from it.
Clarity's read
What the record supports and how the coverage leans. The claims behind it follow.
Reality
- Evidence45
- Adoption
- Insufficient
- Hype gap+20
- Incentives50
- Confidence50
Claim ledger
Ranked by verification strength, evidence, and original report placement.
- [1]
The University of Lincoln study examined patterns of aggression across 100 primate species, including humans.
- [2]
Species with high levels of mild aggression were not necessarily more likely to kill competitors; everyday aggression and lethal violence did not evolve as part of the same simple behavioural spectrum.
- [3]
The study is Majolo, Wakes and Ruta, 'Origins of violence: evolutionary decoupling between mild and lethal conspecific aggression in primates', Evolution Letters, 2026; 10(2): 207.
- [4]
The work was led by Professor Bonaventura Majolo of the University of Lincoln, alongside Dr Samantha Wakes and Professor Marcello Ruta.
- [5]
Many theories about the origins of violence treat aggression as one broad behavioural characteristic, under which species that frequently engage in everyday fights would be expected to show higher levels of lethal violence.
- [6]
The researchers compared five different forms of aggression, ranging from ordinary conflicts to lethal attacks, using a large dataset spanning many primate species.
- [7]
Different types of lethal aggression were moderately associated with one another.
- [8]
The forms of deadly violence showed little connection with mild aggression.
- [9]
Deadly behaviours such as killing adult rivals or infanticide appeared to follow their own evolutionary patterns, largely separate from routine conflict.
- [10]
According to the release, different types of aggression may arise under different social and evolutionary pressures.
- [11]
"Our study shows that the evolution of aggression follows more complex patterns than what earlier models proposed, that it is biologically inaccurate to rank species on the basis of their general propensity for aggression and that we need a more nuanced approach when discussing whether humans are inherently violent."
ReportedSupportedSource: Bonaventura Majolo, Professor of Social Evolution, University of LincolnView cited source - [12]
Researchers in anthropology and evolutionary biology have long debated whether violent behaviour is rooted mainly in deep evolutionary history or is more strongly influenced by social and cultural forces.
- [13]
The release says the pattern suggests the biological and evolutionary mechanisms behind lethal violence are distinct from those that drive everyday conflict.
Sources
1 independent publisher whose own reporting we read for this story.
- sciencedaily.comHumans may not be as hardwired for violence as we thought
1 article · October 6, 2026
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Topics
- Evolution of aggressionFollow
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