Environment
The sixth extinction
The planet is in the midst of drastic biodiversity loss that some experts think may be the next great species die-off. How did we get here and what can be done about it?
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- 20 minutes
Have you ever heard of great auks? They are flightless penguins about half the height of humans. Although very agile under water, they have been described as having a clumsy and rather awkward way of carrying themselves on land. These peculiar birds established one of their biggest breeding grounds on Funk Island, in Newfoundland. Chances are that you have never seen one — and you never will, since great auks became extinct in 1844 when the last two members of the species were killed.
Unfortunately, the fate of the great auk is not unique: a staggering one million species are threatened with extinction worldwide. At least 842 species of plants, fungi and animals are at risk in Canada alone. This is about the total number of bee species and four times the number of mammal species that exist in Canada. It is 842 too many.
Great auks went extinct before we could document their behaviour. We can only glimpse their existence through the journals of travellers. Counts of threatened species often mask what we are really at risk of losing; unique life forms and their complex interactions could disappear before we even have a chance to study and understand them. In Canada, that’s 842 species, each with singular physical attributes, funny behaviours or impressive cognitive skills.
What can we do about it? While biodiversity conservation specialists work actively on protecting threatened species and their habitats, we believe that studying behaviour in endangered and non-threatened species is also essential.
Basic research in animal behaviour, which includes seeking to understand why animals do what they do or studying animal personality, involves developing and improving behavioural tests, procedures, and tools to measure animal behaviour with a particular focus on their welfare.
Researchers working on endangered species often use behavioural measurements to monitor animals’ health with minimal disturbance (for instance, without having to collect tissues, remove animals from their habitat or euthanize individuals for research purposes). Health problems can be detected by observing changes in behaviour or abnormal behaviours, which happens frequently in animals experiencing chronic stress, infected by diseases or suffering from malnutrition. Changes in behaviour often precede reproductive disorders, death and population decline. Studying animal behaviour therefore allows us to detect problems at an early stage and act quickly to solve them.
For example, while working on the conservation of the world’s rarest hamster, which is now critically endangered, we observed abnormal rates of aggression, cognitive disorders and impaired maternal care (associated with high rates of maternal infanticide and cannibalism) in hamsters eating a lot of corn, which happens in corn monocultures. Corn-based diets create a deficiency in vitamin B3, an essential nutrient in all animals, including humans, leading to behavioural and metabolic disorders and ultimately to death. Supplementation in vitamin B3 completely solved behavioural and reproductive disorders in these hamsters.
Using animal behaviour as a conservation tool requires prior knowledge of a species’ behaviours to have a reference standard. For instance, we can use ethograms, which are tables describing all behaviours observed in a species, or information on the frequency of a behaviour in a population to identify abnormal behaviours. To be able to do so, however, we need to study behaviours before a species is threatened. If we wait until a species is in danger of extinction, we will not be able to identify the baseline. How can we tell if the observed behaviours are abnormal otherwise? This is where basic science in animal behaviour matters: it creates reference standards for each behaviour and assesses the behavioural diversity observed in a healthy population to allow people to effectively protect threatened species and biodiversity at large.
The diversity of behaviour that exists in the animal kingdom is astonishing. For instance, chimpanzees use tree branches from which they remove the leaves to literally ‘fish’ soldier ants from their nest and meet their nutritional needs. This impressive (and patience-requiring) behaviour is called termite fishing and is just one of many intriguing behaviours observed in chimps. Researchers recently discovered that these great apes also like to throw rocks at trees to make noise, but the reason why they do it is still not understood. Unfortunately, behavioural diversity is declining because of human activities. We learned that the occurrence of such behaviours in chimpanzee communities is 88 per cent less probable in highly disturbed environments compared to low-disturbance areas, which could further threaten this endangered species, already at risk of extinction because of habitat loss and poaching.
The more we learn about animal behaviour, the fewer differences we see between us and them: animals have emotions, have a language of their own, and can be innovative. These findings humble us and compel us to be more caring towards other living beings.
Monitoring behavioural diversity as we do with other biodiversity indicators to report on biodiversity health and adequately manage wildlife is essential. Biodiversity is indeed much more than just species diversity. Animals of the same species differ in terms of morphology, genetics and behaviour, and those differences are important for species persistence. For instance, particular colours can increase protection against predation, as was seen in the peppered moth of England. During the Industrial Revolution, black morphs became favoured as they were better camouflaged from birds than their white-bodied mates on the trees darkened by soot emissions from coal combustion.
However, the idea that behavioural diversity is also a valuable facet of biodiversity and that it should be integrated into conservation actions is slow to take hold. Criteria on behaviour have yet to be integrated in the guidelines for the status assessment of species in Canada. The situation is similar for the Red List of endangered species at a global scale, although there is evidence that the disappearance of some behaviours is linked to extinction risk.
Differences in behaviour can also be important for species persistence. Basic research in animal behaviour uncovered the great variation in behaviour that exists among and within species. Just like their human counterparts, wild animals have different personalities. When studying eastern chipmunks, we couldn’t help but notice that some of them were more likely to enter the traps baited with peanut butter than others — what we call being “trap happy”. The trap-happiest award certainly goes to the chipmunk we affectionately call Gigi, a seven-year-old female, who enters a new trap as soon as she is released. With Gigi, we hear the next trap door close before we even have the time to get up from where we were handling her a few seconds earlier. There are other chipmunks, however, that we only see once a year in our traps. This propensity to be trapped, or “trapability,” is a behavioural trait that is part of a chipmunk’s personality. Interestingly, personality has been linked to the ability to create friendships, solve complex tasks or innovate in several nonhuman animals. In a rapidly-changing environment, behavioural diversity and specific behavioural skills can be very important. They can allow animals to adjust to climate change and unpredictable food availability. For example, a bolder and more explorative animal is more likely to find a new habitat that protects it from extreme weather or to innovate in expressing new behaviour allowing it to exploit new food resources.
The study of behavioural diversity has also led to profound changes in the way humans define themselves and their place in the animal kingdom. The discovery of termite fishing in chimpanzees is considered to be the first observation of a non-human animal using tools. We previously thought that the use of tools was something that made humans special. The more we learn about animal behaviour, the fewer differences we see between us and them: animals have emotions, have a language of their own, and can be innovative. These findings humble us and compel us to be more caring towards other living beings, and reaffirm our responsibility to protect species threatened by our activities.
Biodiversity conservation, although stemming from basic and applied research, is first and foremost a societal issue. Conservation requires more political and societal involvement from researchers and specialists, but also active contributions from various stakeholders, including each and every one of us.
The question of whether we can ever truly understand animals has always received a lot of attention (as in this podcast). While messages of biodiversity crisis and species extinction worry and discourage a majority of people, our ability as humans to be fascinated by animal behaviour offers a glimmer of hope.
Is it not truly fascinating to know that some animals have a language or personality of their own and that they anticipate and respond to changes in their environment which often escape us, as chipmunks do? Did you know that humans are not the only ones to get facials? A behavioural researcher noticed that brown bears from Alaska can use rocks to scrub or groom their faces. Some animals that we observe every day are great horticulturists (watch bumble bees bite plants in a very specific way to stimulate earlier flowering and get pollen rewards) or paleontologists (harvester ants dig and uncover fossils). The monarch butterfly, recently added on the Red List of endangered species, is a known herbalist, as females select anti-parasitic plants to lay their eggs, a form of self-medication. Such behaviours are not very far from ours. We would not have attributed those behaviours to non-human animals a few years ago, but behavioural studies have deepened our comprehension of wild animals.
The human and social dimensions of biodiversity conservation highlight the need to communicate, raise awareness, foster interest and reconnect politicians and all citizens to nature and biodiversity. This includes informing people about the services animals provide to human society, as well as considering their ability to fascinate. Fascination is key to recreate links between people and nature, and allow the emergence of emotions, reactions and positive behaviour — all indispensable for effective conservation.
The study of animal behaviour has an essential role to play in tackling the current biodiversity crisis, both from a scientific and societal perspective. Integrating knowledge from basic research in animal behaviour could prevent other species from experiencing the same fate as the great penguin that used to be able to roam (albeit awkwardly) not so far away. We shall continue to study and be fascinated by the incongruous behaviours of Canadian wildlife as a way to care for and protect the iconic monarch and caribou, wild bees, and other species at risk of disappearing.
Catherine Čapkun-Huot is a Masters student in biology at the Université du Québec à Montréal working on learning differences in a wild population of eastern chipmunks. Mathilde Tissier is a Liber Ero fellow currently working on the conservation of bumble bees in collaboration with agricultural producers in Quebec and Ontario. The Liber Ero post-doctoral fellowship program fellowship seeks to support early-career scientists to conduct and communicate world-class research that informs conservation and management issues relevant to Canada.
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