Underestimated by many, spotted hyenas (Crocuta crocuta) are providing insight into the roots of human intelligence.
Far from being clownish buffoons, spotted hyenas – also known as laughing hyenas – live in large, complex matriarchal communities, or clans, in which social intelligence is critical. They are fascinating animals – although they look something like dogs, they are more closely related to cats, and closer still to mongooses and civets. Female spotted hyenas are the true clan leaders: they are larger and more aggressive than males, socially dominant, and have even evolved to have male-like external features, including a pseudopenis that is extremely similar in appearance to the male’s sexual organ.
Kay Holekamp, a professor of zoology at Michigan State University, has been studying these gregarious carnivores for many years, and is particularly focused on how they can help us gain a better understanding of why certain animals, including humans and other primates, have developed high intelligence and large brains (which, from a metabolic standpoint, are extremely expensive to maintain). More specifically, she has been looking at spotted hyena society as a means of probing the “social complexity” theory of intelligence, which posits that brainpower provides a significant edge to animals living in complex social groups, where individuals need to be able to anticipate, respond to and manipulate the social behavior of other group members.
The majority of intelligence research in this area has been performed on primates, but Holekamp notes in recent research1 that social complexity theory predicts that “if indeed the large brains and great intelligence found in primates evolved in response to selection pressures associated with life in complex societies, then cognitive abilities and nervous systems with primate-like attributes should have evolved convergently in non-primate mammals living in large, elaborate societies in which individual fitness is strongly influenced by social dexterity.”
In this research, Holekamp acknowledges that much remains to be learned about social cognition in spotted hyenas, but concludes:
Work to date on spotted hyenas has shown that they live in social groups just as large and complex as those of cercopithecine primates [AW: a subfamily of Old World monkeys], that they experience an extended early period of intensive learning about their social worlds like primates, that the demand for social dexterity during competitive and cooperative interactions is no less intense than it is in primates, and that hyenas appear to be capable of many of the same feats of social recognition and cognition as are primates.
While the paper includes much more detail, the following are among Holekamp’s observations regarding spotted hyena social knowledge and skills:
- Individual recognition. Spotted hyenas possess a rich repertoire of visual, acoustic and olfactory signals, which other hyenas can use to discriminate clan members from alien hyenas, to recognize the other members of their social units as individuals and to obtain information about signalers’ affect and current circumstances.
- Kin recognition.Hyenas can distinguish vocalizations of kin from those of non-kin, with intensity of responses increasing with degree of relatedness between vocalizing and listening animals, and kin recognition potentially occurring among hyenas as distantly related as great-aunts and cousins.
- Imitation and behavior coordination. Although hyenas have not been observed to engage in true imitation (that is, replicating a novel act performed by a species member) the way some primates do, they do appear to modify their behavior after observing goal-directed behavior of other hyenas. In addition, they engage in cooperative hunting involving complex coordination and division of labor among hunters. This cooperation, which enables them to capture prey many times their size, involves – at a minimum – communicating by simple rules of thumb (e.g., “move as necessary to keep the prey between you and another hunter”), if not the operation of higher mental processes.
- Social rank and social memory. Spotted hyenas are intensely aware of social rank, and they learn quickly where they and their relatives fit into their clan’s dominance hierarchy. They are able to remember previous interactions they have had with other individuals, and appear to remember the identities and ranks of their clan mates throughout their lives. They apply their knowledge of social ranks in many ways, including to avoid conflict, figure out feeding priority, help them choose appropriate mates, determine which social relationships are desirable to establish and maintain, and when to reconcile after conflicts have occurred.
- Flexible problem-solving. Similar to certain primates, it appears that spotted hyenas are able to achieve short-term goals through a variety of different tactics. As stated in the Holekamp’s research article, “For example, a hyena can avoid aggression by leaving the aggressor’s subgroup, exhibiting appeasement behavior or distracting the aggressor. A hyena can potentially use greeting ceremonies to reconcile fights, reintroduce itself to conspecifics [AW: members of their own species] from which it has been separated, or increase conspecifics’ arousal levels in preparation for a border patrol or group hunt.”
- Tactical deception. One sign of social cleverness, which should be familiar to all humans, is tactical deception. It appears that hyenas may share this sophisticated behavior as well, as anecdotal accounts of hyena deception include a low-ranking hyena noticing an unprotected meal but ignoring it until higher-ranking group mates were out of range, and other low-ranking individuals similarly emit alarm vocalizations in what appear to be deceptive attempts to gain access to food.
Finally, here’s a brief video in which Holekamp shows one of the ways she and her colleagues have been assessing the puzzle-solving skills and memories of spotted hyenas:
So, hats off to laughing hyenas: they may sound comical, but they are seriously smart!
1Holekamp, K., Sakai, S., & Lundrigan, B. (2007). Social intelligence in the spotted hyena (Crocuta crocuta) Philosophical Transactions of the Royal Society B: Biological Sciences, 362 (1480), 523-538 DOI: 10.1098/rstb.2006.1993.