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Animal Behavior
Are Social Species Better Off?
Are we stronger together? A new study highlights the advantages of being social.
Posted November 25, 2024 Reviewed by Devon Frye
Key points
- There are different degrees of sociality.
- Being social has advantages, but also disadvantages.
- Complex social environments create selection pressures to develop complex social skills.
- Fission–fusion societies are special social groups with special challenges.
Despite what we see today in human politics worldwide—that being social and cooperative seems to be out of fashion—there is scientific evidence of an advantage for social individuals, including a new study showing that individuals of social species live longer (Salguero-Gómez 2024).
What Does It Mean to Be "Social"?
The study looked at 152 species from 13 taxonomic classes. They were divided into five groups.
"Solitary" means that individuals spend their time alone and only meet others of the same species when they need to reproduce. Tigers are an example of this. “Gregarious” means that individuals spend time in groups, but their social interactions are loose, like zebras; they stay together, but there is no close association.
“Communal” means that individuals live together in close proximity, often sharing a nesting or roosting site, but are not cooperative breeders. This is the case with some species such as the Purple Martin. The fourth category is “colonial,” meaning that individuals live close together and always live together, such as many nesting birds, some wasps, and coral polyps.
Only the last category is “truly social”: individuals that live in stable, organised groups. These animals know each other personally, they engage in social behaviours such as cooperative breeding, and they often form hierarchical structures. They sometimes cooperate—for example, by hunting and defending their territory together.
We belong to this group. So do elephants, dolphins, meerkats, and lions.
More Social Species Live Longer
Individuals of these species postpone maturity, meaning it takes them a long time to become adults. They also have longer gestation times and, importantly, they have a greater probability of achieving reproduction. Perhaps the solitary tiger has to search too long for the tigress and it would simply be more practical if she lived in the same group.
Of course, there are some disadvantages to living in a group, such as increased competition. A solitary tiger does not have to share his food, and will likely have fewer problems with other males. The tiger only has to find the tigress—whereas his more social relative, the lion, has to compete for females and sometimes even kills the offspring of competitors. Apart from our anthropomorphic view that this is not acceptable, it causes a lot of stress for the cubs—and their mothers too.
This is just one example of how sociality can cause stress, especially for low-ranking individuals. Another, perhaps less well-known, problem in groups is the social transmission of parasites. But some social species have come up with cool strategies to deal with this—for example, primates groom each other to fight parasites together (Kappeler et al. 2015).
More Social Species Get Smarter
Not only do social species live longer; they are also smarter. Or, to be more precise, there is more selection pressure for these species to develop complex social skills (Silk, 2007).
This is because individuals of “truly social” species have many different relationships with members of their group. They need to know who is related to whom in order to form alliances and manage conflicts.
But some “truly social” species face even more selection pressure to be smarter. They live in what are called fission-fusion societies—organised groups that often split into small sub-groups.
The important point is that these subgroups vary in composition. So, on Tuesday I might be with my mum and siblings; the next day I might go out with my girlfriends; and on Thursday, I will be meeting that attractive guy who might become my boyfriend. Fission-fusion societies are only typical of chimpanzees, bonobos, elephants—and, as you might have guessed, humans.
But why are fission-fusion societies so challenging? Not only do you need to know the hierarchy of the group and who is related to whom; you also need to know who is joining your sub-group at the moment and how he or she is related to you and others. You should probably behave yourself when your mum and older brother are around, but you can relax a bit with your girlfriends. You can make eyes at your crush—but don't do it in front of the group leader!
That challenge creates what I talk about often: Sophisticated social cognition.
References
Kappeler, P. M., Cremer, S., & Nunn, C. L. (2015). Sociality and health: impacts of sociality on disease susceptibility and transmission in animal and human societies. Philosophical Transactions of the Royal Society B: Biological Sciences, 370(1669), 20140116.
Salguero-Gómez, R. (2024). More social species live longer, have longer generation times and longer reproductive windows. Philosophical transactions of the Royal Society of London. Series B, Biological sciences, 379(1916), 20220459.
Silk, J. B. (2007). The adaptive value of sociality in mammalian groups. Philosophical Transactions of the Royal Society B: Biological Sciences, 362(1480), 539-559.
