This week's blog comes from a guest writer, Simon Kenworthy! Simon is a 2nd year PhD student part of the London NERC DTP and researches the evolution of culture in primates to better understand how information is tranmitted in social groups. As you will read from his blog, this is an imperative piece of information needed to conserve primates and their behaviours that are essential to their survival. Over to Simon!
What is culture?
When we think of culture, we think of lifestyle variety. To humans, culture stirs images of faraway lands where food tastes different, clothing seems strange and the way of life of the people is one often not comparable to your own. To experience other cultures is a driving force behind global tourism, the thrill of living as another does, expanding your knowledge of humanity to better your own way of life. (Although only often leading to badly cooked Thai cuisine when you arrive home!).
In definitive terms, culture is simply the ideas, customs, and social behaviour of a particular people (1) of society. I for one, have a problem with this definition as it assumes that only ‘people’ can have cultures. Is culture a truly human characteristic? For certain, culture must have evolutionary origins as all human behaviour must, but surely then all life must be able to ‘evolve’ culture. If this is so, then are cultures present in the animal kingdom and what implications would this have for our understanding of social systems and wider conservation?
Evolution and culture
To apply the concept of culture outside humanity, we first must boil down human culture to its most basic characteristics. Human culture I would argue contains 2 key elements.
Populations must show substantially different but frequently repeated behaviours between one another.
These behaviours must persist across generations ie. cultural behaviours must be passed on.
In evolutionary terms, this means that cultural behaviours must show variation and be heritable (although not necessarily genetically). The term ‘cultural evolution’ has been used in one form or another for 200 years to refer to the inheritance of learned behaviours over generations. Since cultural evolution does not require genetic change, it is far quicker than genetic evolution. I’ll give you an example. In 5000 years, humans have gone from routinely using stone tablets to computer tablets, with learnt behaviours regarding computational management easily picked up by young children. There is unlikely any genetic change which makes us more amenable to computational thought or actions, only learning. Cultural evolution will likely be paramount in our rapid adaptation to the selection pressures which climate change may bring, far quicker than wating for genetic mutations to allow us to breathe underwater... much quicker to learn to scuba dive. So, my point is this, if it is accepted that humans can teach and learn behaviours which may lead to rapid adaptation to changing environments, animals which show cultural variation could adapt quicker to environmental change than animals which rely on genetic change alone.
Culture in the animal kingdom
A potential evolutionary mechanism for cultural development in a species is if the species has a wide geographical distribution, allowing for a variation in ecosystem or lifestyle strategies. Crucially though, these populations must be isolated from one another to decrease cultural blending. Few species fit this criterion but a well-documented species include orcas and great apes.
Orcas can be found from Antarctica to the Arctic but what isolates populations from one another is their prey specialisms. Orcas, even living geographically close groups, can specialise in prey items. For example, in the NE Pacific, 3 groups feed off exclusively marine mammals, one salmon and another on sharks, others famously beach themselves to snatch a baby sea lion!(1) Each of these prey types require very different hunting strategies to capture. The use of sound to perceive environments or prey, sonar, is finely tuned to optimally detect a specific sized object. For example, insectivorous bats in dense environments vocalise at higher frequencies than fish-eating bats in open environments so they can detect small leaves to avoid collisions and smaller prey. Orcas which hunt fish also utilise this adaptation to their sonar, but interestingly, all of their vocalisations are at higher frequency than orcas which hunt larger prey such as whales, with differences in group size and social organisation also observed (2). This means that behaviourally specialised individuals are unlikely to move between groups due to inability to catch prey, lack of understanding of unique social organisations and communication mismatch.
Chimpanzees are famous for their human like tool use, using sticks to dip for ants, hammering nuts and use of baiting to name a small variety (3). These behavioural variants are often unique to one population or group and allow the group to exploit a niche perhaps closed off to other species or if environments change to remove specific food types. Chimpanzees like other great apes require a long period of learning to perfect these behaviours. Chimpanzees live in fission-fusion societies, meaning movement between groups is common. However, if behavioural specialties are different between groups, much like genetically diverse populations, behaviourally diverse populations are unlikely to mix.
Within orcas and chimpanzees, behavioural variation between populations means the species as a whole is more plastic to environmental change, if one culture is lost, another culture can survive due to behavioural differences. This surely makes them flexible to environmental change, right...?
Culture and conservation
Cultural variation in orcas and chimpanzees sounds great, that surely some populations must survive if others are threatened. However, this assumes that cultures are conserved equally but this is not the case. Commonly, some populations are declining more rapidly than others with chimpanzee numbers living close to forest edges declining rapidly due to human-wildlife conflict and orcas living in commercial fisheries vulnerable to accidental entrapment. This means that some behaviours may be lost from the species and unlikely to be learnt quickly by already specialised groups. Unlike orcas, chimpanzee habitats are in great danger of loss through deforestation, as well as decreasing food frequency. This means that unique chimpanzee cultural behaviours are in danger of being lost from the species (4).
Therefore, when discussing what species to conserve and in what area, behavioural
specialisms or cultures must be taken into account to conserve behavioural adaptability to environmental change.
Orcas and chimpanzees are undeniably social and intelligent, capable of adaptive behaviours and innovative thought. It is most likely therefore that socially complex and intelligent animals are most capable of sustained behavioural variation between populations. This highlights the need for greater cultural evolutionary research in numerous candidate social species which will need to be accounted for during conservational planning. Happily though, chimpanzee cultural heritage sites have been recently planned by the United Nations, protecting a chimpanzee population which uses stone (5) hammers to crack nuts, and charities and research programmes aim to gain similar cultural conservation status for orcas. It won’t be too long until sociality is integrated into conservation policy, watch this space!
Laland KN, Hoppitt W. Do animals have culture? Evol Anthropol Issues News Rev. 2003;12(3):150–9.
Yurk H. Vocal culture and social stability in resident killer whales (Orcinus orca) [Internet]. University of British Columbia; 2005 [cited 2020 Dec 17]. Available from: https://open.library.ubc.ca/cIRcle/collections/ubctheses/831/items/1.0074875
Sanz CM, Morgan DB. Ecological and social correlates of chimpanzee tool use. Philos Trans R Soc B Biol Sci. 2013 Nov 19;368(1630):20120416.
Marshall M. Unique chimpanzee cultures are disappearing thanks to humans [Internet]. New Scientist. [cited 2020 Dec 15]. Available from: https://www.newscientist.com/article/2195890- unique-chimpanzee-cultures-are-disappearing-thanks-to-humans/
Major UN meeting on wildlife to address critical threats to migratory species. UN Environment. 2020 [cited 2020 Dec 17]. Available from: http://www.unenvironment.org/news-and-stories/press- release/major-un-meeting-wildlife-address-critical-threats-migratory-species
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