Joe Nedelec Ph.D.

The Nature of Crime

Of Crime, Criminality, and Nature

Are humans the only animals who commit crime?

Posted Jun 30, 2015

In my first post I reviewed the general assumptions of biosocial criminology, one being that humans are as much a part of nature as any other animal.  In this post, I’d like to dive into that claim with a little more detail.  (It’s a good idea to read my first post if you haven’t already.)

At the outset, I contend that making the claim that we are just another node in the network of nature necessitates the inclusion of a biological perspective in explaining human behavior.  So, invoking only cultural and other social explanations — as is done in most criminological and sociological theories — is not enough to explain human behavior.  Essentially, once you accept that humans are a product of nature then explanations based on biology apply to all aspects of the human condition.  This reasoning applies to all behavior, including behavior that we would consider ‘criminal’.

So how can biological explanations assist in examining criminal behavior?  As with the study of our morphology, evolutionary explanations can help answer such a question.  Both nonhuman and human animals are presented with general overarching adaptive problems: survival and reproduction.  While the nuances of surviving and reproducing in the animal kingdom obviously vary from species to species, these general adaptive problems are solved with functional behaviors that are fairly consistent: eat and try to avoid being eaten, woo and/or choose potential mates, and compete — often intensely — when engaging in any of these tasks.  It is in the competition so evident in nature that one finds criminal behavior.1 

But how, you might ask, could nonhuman behavior ever be considered criminal?  Well, you are not alone.  Take for example the experience of my colleague, fellow biosocial criminologist Dr. Brian Boutwell (Associate Professor at Saint Louis University).  Brian submitted a manuscript to a peer-reviewed biology journal arguing for the application of an evolutionary perspective to criminal behavior.  The response from the Editor was one that biosocial criminologists are often presented and I provide it here verbatim:

There is no biological basis for the concept of criminality — that which is defined as "criminal" is a purely human social construct as proven by the facts that 1) no animal behaves "criminally" and 2) that which is defined as "criminal behavior" differs from culture to culture. Thus, all attempts to relate the "deep evolution of criminality" to reproductive behaviors, etc. are inherently nonsensical.   

For now, let’s put aside the odd fact that the Editor, a biologist, was informing Brian, a criminologist (his professional affiliation indicated as much), about the nature of crime.  Let’s also not delve into a discussion about the cultural relativity of crime, especially given what is defined as criminal behavior is actually quite consistent from culture to culture and over time.  To wit, few cultures openly accept behaviors such as thievery, murder, and assault.  Instead, let’s focus on the Editor’s first point which is the impetus for this post.

Do nonhuman animals behave criminally? 

To address the issue we need to focus on another word the Editor used in their2 rebuke of Brian’s arguments: criminality.  Experts often differentiate between ‘crime’ and ‘criminality’, where crime refers to an act and criminality refers to the propensity or inclination to engage in criminal or antisocial acts.  For the most part, legal scholars concern themselves with crime: legislation, case law, and the like; criminologists concern themselves with criminality: assessing why individuals differ in their propensity to engage in antisocial behavior.  So, the focus is on behavior and not necessarily the legality of the behavior.3  Thinking in this way leads criminologists to study antisocial behaviors; i.e., acts which violate the interests of one party to the benefit of another party in contravention of normative behavior of the group to which the parties belong.  As pointed out by other Psychology Today contributors, normative behavior for human and nonhumans alike is often of a cooperative or prosocial nature.

“That’s all fine, but you haven’t answered the question”, I hear you say.  Well, as the saying goes (more or less) there’s nothing like a little data — or some poignant examples — to ruin a good theory.  In this instance, it’s the Editor’s theory that only humans behave criminally or engage in antisocial behavior.  Let’s look at some examples from the animal kingdom of what I would consider antisocial behavior (i.e., criminality).  Crucial to this discussion is the point that these examples are not representative of typical behavior of the species, but rather illustrate that nonhumans engage in acts that, prima facie, are antisocial.

Exhibit A: Theft

Thievery is an antisocial act which proliferates in both human and nonhuman animals.  The video below illustrates an example of thievery among a nonhuman primate where a smaller monkey waits patiently for a larger monkey to peel a banana (it's cliché, I know) and then he snatches the peeled banana and runs. 

Key to calling this an antisocial or criminal act is that the ‘offender’ is aware of a risky contravention of social rules — why run away after taking the banana if there isn’t a known violation and risk to the behavior?

Exhibit B: Substance abuse (and abstention)

The highly studied vervet monkeys of St. Kitts in the Caribbean exhibit some incredible similarities to humans in their use, abuse, and abstention from alcohol (Palmour et al., 1997).  In the video below several monkeys are shown drinking from a variety of alcoholic and non-alcoholic drinks.  Additionally, the predictable effects of the libations are also shown.

I don’t consider their snatching of drinks from humans to be antisocial behavior – the monkeys are just obtaining the drinks that are provided in their environment in the same way they would by grabbing fruit from a tree.  However, the excessive and persistent drinking meets the behavioral definition of alcoholism (antisocial behavior).  Interestingly, the rates of social drinking, excessive drinking, and abstention from alcohol among these monkeys are eerily similar to those seen in humans.  Some monkeys are social drinkers, some are excessive drinkers (alcoholics), and some avoid alcoholic drinks altogether.  Additionally, researchers have also observed an increased amount of alcohol use among the offspring of excessive drinkers relative to the offspring of social drinkers and monkey teetotalers Palmour et al., 1997).  These observations point toward a differential propensity towards alcoholism among these nonhuman primates (i.e., criminality).

Exhibit C: Gang violence/warfare

Imagine the following scenario: there are two groups of a species that each live in neighboring territories that are large enough to sustain either group.  Male members of one group, the invaders, band together and enter the territory of the other group, the defenders.  Upon spotting a member of the defenders, the invaders spring into action and violently attack any defender that can be caught.  Verbal assaults are also levied between the groups and some individuals lose their lives in the attack.  Unprovoked invasion, assault, and killing — these acts all represent what I would consider antisocial behavior.  This scenario is precisely what was observed in this astonishing and powerful (as well as gruesome, so heads-up) footage of chimpanzees recorded by the BBC:

(Despite the violence and gore, note the cooperative behavior at the end of the clip and how it contrasts with the clip above illustrating theft.)

Exhibit D: Sexual coercion/rape

The study of reproduction in the animal kingdom is simply fascinating and underlying the various ways in which the multitude of species go about the business of reproducing is one key fact: fail to reproduce and you are, on average, an evolutionary dead-end.  Thus, the pressure to be reproductively successful is all-encompassing.  That’s why some males take the risk of being freakin’ eaten alive by their female partners in order to mate!  Females in over 80 species are known to feast on their mates at some point during sex (Judson, 2002).  In many more species, males have but one chance to reproduce because their members — are you ready for this, guys? — break off and remain in the vaginal tract of their female partner.  With such illustrations of extreme steps taken to reproduce, it is not surprising to see rampant examples of what we would clearly label as sexual coercion or rape among nonhuman animals. 

Although rape is not always the primary mating strategy employed, it is so common in nature that members of many species have evolved anti-rape defense mechanisms.4  Forced copulation with an undesirable partner is a costly endeavor from an evolutionary standpoint and so anti-rape defense mechanisms have co-evolved along with propensities towards sexual assaultive behavior. Take for example the structure of genitalia in a number of duck species.  In these species the males have penises that are coiled in a corkscrew shape and the females have vaginas that are also coiled; but, and this is the fascinating part, the vagina is coiled clockwise and the penis is coiled counter-clockwise.  The only way in which copulation can successfully occur is if the female relaxes muscles in her vaginal wall to straighten out the coils.  To prevent any unwanted copulation, the female simply flexes her vaginal muscles, tightens the coils, and the penis is not able to penetrate far enough into the vagina.  As a result, any sperm released by the male will simply wash away into that lake that you enjoyed swimming in this summer.  (Sorry!)  The structure and functional behavior of the vaginas in these species are a direct result of the high prevalence of sexual coercion over evolutionary time.  As evolutionary biologist Menno Schilthuizen (2014) states in his fascinating book on the incredible variety of genitalia in nature, these structures in mallards have “evolved in sexually antagonistic coevolution: a mutual series of steps in which any rapist intentions of the male had been countered by vagina blockades of the female” (128; emphasis added).  I’d say that rapist intentions and actions would certainly qualify as antisocial behavior.     

A female mallard (brown head) attempts to avoid the sexually assaultive behaviors of three males (green heads).
Source: AJ/Flikr

Another example of rape in nature is the sagebrush cricket. In this species, the female mounts the male and the male curves his back upward to link genitalia with the female.  A male first attracts a female with a pleasant tune by rubbing his legs together.  To keep her around long enough to do the deed, he offers two small fleshy white wings on his back that the female can then nibble on (the females eat the nutritious fluid that is produced when the wings are injured).  The wings are not for flying and appear to be solely for the purpose of mating.  Females prefer virgin males because there is more nourishment to be had from undamaged wings; however, males seek to mate with as many females as possible.  Fortunately for the male, and unfortunately for the female, the small white wings are hidden and can’t be fully inspected from afar.  Therefore, when females are in close proximity and scrutinizing the quality of the male’s wings the male curves his back to link genitalia and small teeth-like structures on the male’s back trap the female until the male’s back is no longer curved (aka, a gin trap).  A virgin male doesn’t require the use of the gin trap as the female is happy to stay and gobble on his undamaged, pristine wings.  A male who has already been around the block a few times, however, springs the gin trap on the female as she’s likely to take off when she spots the evidence of his philandering.  Notably, experts have concluded — after experimental manipulations of male morphology related to female mating preferences — “the gin trap functions as a device by which males with insufficient hind-wing material are able to force copulations upon females unwilling to accept their spermatophores” (Sakaluk et al, 1995: 65; emphasis added).  I’m not sure of a better description of rape than forced copulation upon an unwilling other. 

Not convinced of the criminality of nonhuman animals?  I present the male scorpionfly.  In the words of evolutionary biologist Olivia Judson (speaking through her sex advice providing persona, Dr. Tatiana), “Scorpionflies have an old-fashioned mating system: he pays for supper, she puts out” (Judson, 2002: 116).  Male scorpionflies engage in three different mating strategies in this old-fashioned system.  First, nuptial gift version one: he can provide a dead insect to the female and mount her while she eats.  Second, nuptial gift version two: he can produce a gelatinous lump secreted from salivary glands that can be served as a meal to the female, and here too, he can mount her while she eats. 

ron_n_beths pics/Flikr
The matship in this picture illustrates the mating preferred by female scorpionflies: a meal (note insect being offered) and no forced copulation.
Source: ron_n_beths pics/Flikr

Females prefer males who arrive with a nuptial gift in, uh, hand and approach them. Females will avoid and flee from guys down on their luck who arrive to the party without something for her to munch on.  But, it takes time and energy to find dead insects and it’s also a risky affair: other scorpionflies and other species want the food source as well and will fight for it.  Time and energy are also required to generate the yummy gelatinous lump. 

Enter the male’s third option: offer the female no food and instead sneak up on her, grasp her with claspers, and mount her.  Then, and this is the incredible part, the male will make use of a notal organ that is placed on the female’s wings effectively holding her down and preventing her escape.  Much like the sagebrush cricket’s gin trap, the male scorpionfly’s notal organ appears to be designed specifically to aid with rape.  Experimental manipulation and testing of alternative hypotheses have resulted in the conclusion that “the notal organ is designed for rape: it functions to secure a mating with an unwilling female and to retain her in copulation for the period needed for full insemination” (Thornhill and Palmer, 2000: 64; emphasis added).5  Yet another solid example of criminality in the wild.

Do nonhuman animals behave criminally? 

Absolutely they do!  Like Brian, I was astonished by the Editor’s claim that “no animal behaves ‘criminally’”.  How could this highly educated and esteemed person be ignorant of the types of behaviors that I’ve discussed above?  How is it possible to so easily separate humans from the rest of nature?  How is it that social scientists such as Brian and I are able to plainly see that antisocial behavior is not something unique to humans?  What the hell do we know about insect behavior?  We’re damn criminologists!  It’s a testament to a few points outlined below and that I will touch on throughout many of my posts. 

First, when it comes to crime everyone is an expert.  Crime, criminality, and notions of justice are indelible aspects of the human condition.  Rare is the person who does not have an opinion on what causes crime or what societies should do about crime.  Thus, we are presented with the odd situation wherein a neophyte (regarding criminology) gladly — and with much conviction — informs an expert on crime and criminality that criminal behavior is a mere epiphenomenon of our social processes and entirely without any biological bases, Q.E.D.

Second, the Editor’s comments speak to the dominant argument that is so pervasive in criminology, sociology, and other social sciences that it has seeped into the crevices of other disciplines and assimilated into the neural fibers of otherwise highly intelligent individuals: antisocial behavior is solely caused by social forces.  The mental gymnastics requisite of such a position is astounding as it necessitates that human behavior in general — or at least one component of human behavior specifically — is in no way impacted by our evolutionary history, our neurochemical processes, our hormonal fluctuations, or our genetic differences. Imagine a biologist’s reaction to a sociologist claiming that insects, mallards, chimpanzees, and monkeys were engaging in certain behaviors due to the social construction of meaning created by these species.  You chuckle at the thought, and rightly so, but why is it not similarly ridiculous to do so for human behavior? 

It’s a question we biosocial criminologists often discuss and the frustration has led us to take to the bottle on more than one occasion.  Perhaps those vervet monkeys have had to deal with the peer-review process as well?!


(I want to thank Dr. Brian Boutwell for allowing me to use the review he received.)

End Notes

1. Cooperation is also obviously used to survive and reproduce and there is considerable overlap between nonhuman and human animals in their cooperating behaviors (see Mark Bekoff’s posts).  This additional overlap serves to only further support the application of a biosocial perspective to human behavior. 

2. Steven Pinker (2014) says I can use “their” here instead of the awkward “his/her” so take it up with him, Internet.

3. As I’ll discuss in future posts, criminologists examine behaviors that are illegal but also behaviors that are considered analogous to criminal behavior, such as substance use or risky sexual behaviors, and the lifestyles associated or congruent with engaging in antisocial behaviors.

4. To be clear, I’m talking about behavioral and structural mechanisms that help to reduce the likelihood of being the victim of sexual coercion and in no way proposing the sort of nonsensical argument recently put forth by a certain uninformed American politician.

5. It is of interest to note that in the examples of rape cited here it’s the males who are less desirable that are engaging in rape as a mating strategy.  Additionally, note that the sexually assaultive behavior is not normative but rather a final resort to avoid the incredible costs of genetic oblivion.  In other words, it fits our definition of antisocial behavior.


Judson, O. (2002). Dr. Tatiana's sex advice to all creation: The definitive guide to the evolutionary biology of sex. New York, NY: Owl Books.

Palmour, R. M., Mulligan, J., Howbert, J. J., & Ervin, F. (1997). Of monkeys and men: vervets and the genetics of human-like behaviors. The American Journal of Human Genetics, 61, 481-488.

Pinker, S. (2014).  The sense of style: The thinking person’s guide to writing in the 21st Century.  New York, NY: Viking.

Sakaluk, S. K., Bangert, P. J., Eggert, A. K., Gack, C., & Swanson, L. V. (1995). The gin trap as a device facilitating coercive mating in sagebrush crickets. Proceedings of the Royal Society of London B: Biological Sciences, 261, 65-71.

Schilthuizen, M. (2014). Nature's nether regions: What the sex lives of bugs, birds, and beasts tell us about evolution, biodiversity, and ourselves. New York, NY: Viking.

Thornhill, R., & Palmer, C. T. (2001). A natural history of rape: Biological bases of sexual coercion. MIT press.

Fore more information on biosocial criminology check out the University of Cincinnati's School of Criminal Justice Online Program and the Biosocial Criminology Association.