posts: 41950

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                        "text": "When it comes to wildlife conservation, it\u2019s usually the large charismatic mammals that keep our attention, and make us reach into our pockets.{ref}Krause, M., & Robinson, K. (2017). ",
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                        "url": "https://www.jstor.org/stable/26393299",
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                            {
                                "text": "Charismatic species and beyond: how cultural schemas and organisational routines shape conservation",
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                        "text": ". ",
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                                "text": "Conservation and Society",
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                        "text": ", ",
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                                "text": "15",
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                        "text": "(3), 313-321.{/ref} People love pandas, tigers, polar bears and elephants and want to protect them. We see them through the lens of human interactions: we see them communicate; play; and bond with other animals in the group. It has been shown that we feel a closer emotional response to animals if we see humanistic behaviors in them.{ref}Batt, S. (2009). ",
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                        "url": "https://academic.oup.com/biohorizons/article/2/2/180/254452",
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                                "text": "Human attitudes towards animals in relation to species similarity to humans: a multivariate approach",
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                        "text": ". ",
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                        "children": [
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                                "text": "Bioscience Horizons",
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                        "text": ", 2(2), 180-190.{/ref}",
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                        "text": "Favouritism towards these large mammal species might be seen as leading with the heart. If we were to take a rational approach to conservation, would we prioritize differently?",
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                        "text": "The head and the heart might not be as conflicted as we think. This is because large mammals ",
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                        "children": [
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                                "text": "are",
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                        "text": " the ones that are at greatest risk of extinction. For millennia, large mammals have been the first to go. This is still the case today.",
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                "text": [
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                        "text": "Large mammals have been at risk since the arrival of humans",
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                                "text": "Earth has been through five major extinctions. None of these events were selective towards a specific size of animal; over the past 66 million years (the \u2018Cenozoic period\u2019), neither small nor large mammals were more vulnerable.{ref}Smith, F. A., Smith, R. E. E., Lyons, S. K., & Payne, J. L. (2018). ",
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                                "url": "https://science.sciencemag.org/content/360/6386/310",
                                "children": [
                                    {
                                        "text": "Body size downgrading of mammals over the late Quaternary",
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                                "text": ". ",
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                                        "text": "Science",
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                                "text": ", ",
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                                "children": [
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                                        "text": "360",
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                                "text": "(6386), 310-313.{/ref}",
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                                "text": "This all changed with the arrival of humans. Until then, there had been an abundance of large mammals. Mammoths; giant ground sloths; wooly rhinoceros and sabertooth tigers were found across all habitable continents.{ref}Smith, F. A., Smith, R. E. E., Lyons, S. K., & Payne, J. L. (2018). ",
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                                "url": "https://science.sciencemag.org/content/360/6386/310",
                                "children": [
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                                        "text": "Body size downgrading of mammals over the late Quaternary",
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                                "text": ". ",
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                                        "text": "Science",
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                                "text": ", ",
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                                        "text": "360",
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                                "text": "(6386), 310-313.{/ref} Now, most of the world\u2019s large mammals can only be found in Africa.",
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                                "text": "Most \u2013 more than 178 species \u2013 of the world\u2019s largest mammals went extinct at the Quaternary Megafauna Extinction (QME); during the Pleistocene period which occurred between 52,000 and 7,000 BC.{ref}Barnosky, A. D. (2008). ",
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                                "url": "https://www.pnas.org/content/105/Supplement_1/11543",
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                                    {
                                        "text": "Megafauna biomass tradeoff as a driver of Quaternary and future extinctions",
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                                "text": ". ",
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                                "children": [
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                                        "text": "Proceedings of the National Academy of Sciences",
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                                "text": ", ",
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                                "children": [
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                                        "text": "105",
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                                "text": "(Supplement 1), 11543-11548.{/ref} There is growing evidence that this megafauna extinction event was primarily driven by human hunting ",
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                                "children": [
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                                        "text": "[we look at this in detail in a related article]",
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                                "text": ". When we track man\u2019s footsteps across the continents we find a wave of extinctions in its shadow. Humans arrived, and soon after the mammals were gone.",
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                                "text": "Another key piece of evidence that humans were the driving force is the fact that it was ",
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                                        "text": "large",
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                                "text": ", not small animals that were killed off. In the chart we see the size distribution of mammals at this extinction event.{ref}Lyons, S. K., Smith, F. A., & Brown, J. H. (2004). ",
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                                "url": "https://biology.unm.edu/fasmith/Web_Page_PDFs/Lyons_et_al_2004_EER.pdf",
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                                    {
                                        "text": "Of mice, mastodons and men: human-mediated extinctions on four continents",
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                                "text": ". ",
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                                "children": [
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                                        "text": "Evolutionary Ecology Research",
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                                "text": ", 6(3), 339-358.{/ref} This shows the number of mammal species which fall into each size category (with the largest on the right, and smallest on the left). The mammals that went extinct on each continent are coloured black.\u00a0",
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                                "text": "We see very clearly that there is a strong bias towards the largest mammals. In Australia, 88% of all megafauna (animals weighing more than 40 kilograms) went extinct; in North America this was 83%; and 72% in South America. Africa was less hard-hit at the QME because hominids had evolved there over millennia before and so mammals had become more adapted to human pressures.",
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                                "text": "A size bias of this magnitude was completely unique to the fossil record. Previous extinction events did not discriminate between small or large animals \u2013 it wiped them all out. This event marked something new: the arrival of humans.",
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                        "text": "Why are larger mammals at greater risk of extinction?",
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                        "text": "Humans are megafauna species ourselves (the average adult weighs more than 40 kilograms). Our arrival therefore marked the entrance of a new megafauna predator to compete with. An effective one, as it turns out.",
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                        "text": "We preferentially hunt larger animals rather than smaller ones. They are easier to spot and track; we get much more meat from them; we could hunt them at a distance once we developed long-range weapons; and some harvest body parts for other uses such as their tusks, bones, for medicine, or for trophy-hunting.\u00a0",
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                        "text": "But large mammals are not just at higher risk because we\u2019re more likely to hunt them. They have slower reproduction cycles \u2013 they live longer lives, and reproduce less frequently. This means they are slow to restore their populations once they become depleted. Combined, these make a perfect recipe for overhunting.",
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                        "text": "A new predator on the scene also creates more competition for resources. Megafauna have high energy demands, meaning they need a lot of food to survive. It\u2019s estimated that 10,000 kilograms of prey is needed to support a 90 kilogram carnivore over its lifetime; this means the depletion of food resources has impacted populations of large carnivores such as tigers and leopards.{ref}Carbone, C., & Gittleman, J. L. (2002). ",
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                        "url": "https://science.sciencemag.org/content/295/5563/2273.abstract?casa_token=AiqL8vzGB8IAAAAA:wlZNGzBLJl85L5NIn624FcmmUGqobPJ5ZSbcSSQ0eJM9dP5gl909ejPV_M0IiIWNiEr-OLl-fSfsf400",
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                                "text": "A common rule for the scaling of carnivore density",
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                        "text": "(5563), 2273-2276.{/ref}",
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                        "text": "Large mammals are still at the highest risk today, but pressure on smaller mammals is also rising",
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                                "text": "Livestock have spared many wild animals from human hunting. But the poaching of elephants, rhinos, hippos and the rest of the world\u2019s largest mammals still goes on today. Humans hunt them for wild meat, or for their body parts.",
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                                "text": "Large mammals are still at the highest risk of extinction. In the chart we see the share of mammals that went extinct during the Pleistocene period (in brown), and the share that are at risk of extinction today (in green).{ref}Ripple, W. J., Newsome, T. M., Wolf, C., Dirzo, R., Everatt, K. T., Galetti, M., ... & Van Valkenburgh, B. (2015). ",
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                                "url": "https://advances.sciencemag.org/content/1/4/e1400103",
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                                        "text": "Collapse of the world\u2019s largest herbivores",
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                                "text": ". ",
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                                        "text": "Science Advances",
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                                "text": "(4), e1400103.{/ref} These are categorised by body mass, with the smallest mammals on the left, and largest on the right.\u00a0",
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                                "text": "The distribution today is a close mirror of the past. 86% of mammals weighing over one tonne today are threatened with extinction; 84% of species in this category went extinct in the past. As we move to smaller and smaller mammals, the percentage at risk of extinction drops off.",
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                                "text": "This \u2018body size downgrading\u2019 is therefore likely to continue. Researchers estimate that based on current trajectories, within the next few centuries median global body mass could fall from 17 kilograms down to 7 kg. In Africa, from 27 kg to 11 kg; and from 4.4 kg to 1.7 kg in South America.{ref}Smith, F. A., Smith, R. E. E., Lyons, S. K., & Payne, J. L. (2018). ",
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                                "url": "https://science.sciencemag.org/content/360/6386/310",
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                                        "text": "Body size downgrading of mammals over the late Quaternary",
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                                "text": ". ",
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                                "text": ", 360(6386), 310-313.{/ref}",
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                                "text": "But, there\u2019s one important difference today: humans are also now putting increasing pressure on smaller mammals. Millennia ago our impact was direct in the form of hunting. Human populations were small (",
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                                        "text": "less than 5 million",
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                                "text": ") and we used very little land for farming. But since then we have used more and more land for agriculture. We cut down ",
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                                "url": "https://ourworldindata.org/world-lost-one-third-forests",
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                                        "text": "one-third of the world\u2019s forests",
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                                "text": ", took over wild grasslands, and fragmented the habitats of many species. This impact has affected both large and very small mammals.",
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                                "text": "To protect our largest mammals we need to stop poaching. This is the biggest threat to these animals. To protect smaller ones we need to stop encroaching on their habitats. This means bringing deforestation to an end, and limiting the expansion of agriculture. Better yet, we could give wildlife some of this land back by rewilding and replanting on land we no longer need.",
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                                "text": "It is often the biggest, most charismatic animals that steal our hearts. But they\u2019re actually the ones that are most under threat. If we don\u2019t want to lose them, we need to take action. This is at least one area where it makes sense to follow our hearts.",
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        "type": "article",
        "title": "The largest mammals are at greatest risk of extinction",
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        "dateline": "March 24, 2021",
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    "createdAt": "2021-03-24T15:47:14.000Z",
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    "updatedAt": "2022-12-14T13:59:04.000Z",
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