Anno IV - Numero 6
Il peggior analfabeta è l'analfabeta politico.
Bertolt Brecht

giovedì 16 novembre 2017

Conserve elephants. They hold a scientific mirror up to humans

The symbol of the World Wide Fund for Nature is a giant panda. The panda’s black-and-white pelage certainly makes for a striking logo. But, though pandas are an endangered species, the cause of their endangerment is depressingly quotidian: a loss of habitat as Earth’s human population increases


A better icon might be an elephant, particularly an African elephant, for elephants are not mere collateral damage in humanity’s relentless expansion. Often, rather, they are deliberate targets, shot by poachers, who want their ivory; by farmers, because of the damage they do to crops; and by cattle herders, who see them as competitors for forage.

In August 2016 the result of the Great Elephant Census, the most extensive count of a wild species ever attempted, suggested that about 350,000 African savannah elephants remain alive. This is down by 140,000 since 2007. The census, conducted by a team led by Mike Chase, an ecologist based in Botswana, and paid for by Paul Allen, one of the founders of Microsoft, undertook almost 500,000km of aerial surveys to come to its conclusion — though the team were unable to include forest elephants, a smaller, more reclusive type that live in west and central Africa, and which many biologists think a separate species.

That most of the decline has been brought about by poaching is scarcely in doubt. Seizures of smuggled ivory, and the size of the carved-ivory market compared with the small amount of legal ivory available, confirm it. But habitat loss is important, too — and not just the conversion of bush into farmland. Roads, railways and fences, built as Africa develops, stop elephants moving around. And an elephant needs a lot of room. According to George Wittemyer of Save the Elephants (STE), a Kenyan research-and-conservation charity, an average elephant living in and around Samburu National Reserve, in northern Kenya, ranges over 1,500 square kilometres during the course of a year, and may travel as much as 60km a day.
The long road to knowledge

The question, then, is whether elephants and people can ever co-exist peacefully. And many of those who worry that the answer may be “no” fear the loss of more than just another species of charismatic megafauna. Elephants, about as unrelated to human beings as any mammal can be, seem nevertheless to have evolved intelligence, and possibly even consciousness. Though they may not be alone in this (similar claims are made for certain whales, social carnivores and a few birds), they are certainly part of a small and select group. Losing even one example of how intelligence comes about and makes its living in the wild would not only be a shame in its own right, it would also diminish the ability of biologists of the future to understand the process, and thus how it happened to human beings.

Most of what is known about elephant society has been found out by STE’s study in Samburu and by an even longer-running project, led by Cynthia Moss, at Amboseli National Park, in the country’s south. Both use a mixture of good, old-fashioned fieldcraft and high-tech radio collars that permit individual animals to be tracked around by satellite.

Dr Moss began her work in Amboseli in 1972, after collaborating in Tanzania with Iain Douglas-Hamilton, a zoologist who had been studying the animals since 1965 (and who is, coincidentally, the uncle of our Books and Arts editor). In 1993 Dr Douglas-Hamilton, who had held various conservation-related jobs in the interim, followed suit by creating STE and recruiting Dr Wittemyer to set up a research project in Samburu. That project now monitors 70 family groups comprising about 300 adult females and their offspring, and also around 200 adult males. Since they began work, Dr Wittemyer and his team have collected more than 25,000 field observations of what the animals are up to, and around 4m individual satellite locations.

Dr Wittemyer argues that, human beings aside, no species on Earth has a more complex society than that of elephants. And elephant society does indeed have parallels with the way humans lived before the invention of agriculture.

The nuclei of their social arrangements are groups of four or five females and their young that are led by a matriarch who is mother, grandmother, great-grandmother, sister or aunt to most of them. Though males depart their natal group when maturity beckons at the age of 12, females usually remain in it throughout their lives.

Within a group, most adult females have, at any given moment, a single, dependent calf. They will not give birth again until this offspring is self-sufficient, which takes about four years. From a male point of view, sexually receptive females are therefore a rare commodity, to be sought out and often fought over. Such competition means that, though capable of fatherhood from the age of about 14, a male will be lucky to achieve it before he is in his 20s. Until that time arrives, he will be seen off by stronger rivals.

Were this all there was to elephant society, it would still be quite complex by mammalian standards — similar in scope to that of lions, which also live in matriarchal family groups that eject maturing males. But it would not deserve Dr Wittemyer’s accolade of near-human sophistication. Unlike lions, however, elephants have higher levels of organisation, not immediately obvious to the observer, that are indeed quite humanlike.

First of all, families are part of wider “kinship” groups that come together and separate as the fancy takes them. Families commune with each other in this way about 10% of the time. On top of this, each kinship group is part of what Dr Douglas-Hamilton, a Scot, calls a clan. Clans tend to gather in the dry season, when the amount of habitat capable of supporting elephants is restricted. Within a clan, relations are generally friendly. All clan members are known to one another and, since a clan will usually have at least 100 adult members, and may have twice that, this means an adult (an adult female, at least) can recognise and have meaningful social relations with that many other individuals.

A figure of between 100 and 200 acquaintances is similar to the number of people with whom a human being can maintain a meaningful social relationship — a value known as Dunbar’s number, after Robin Dunbar, the psychologist who proposed it. Dunbar’s number for people is about 150. It is probably no coincidence that this reflects the maximum size of the human clans of those who make their living by hunting and gathering, and who spend most of their lives in smaller groups of relatives, separated from other clan members, scouring the landscape for food.

Dealing with so many peers, and remembering details of such large ranges, means elephants require enormous memories. Details of how their brains work are, beyond matters of basic anatomy, rather sketchy. But one thing which is known is that they have big hippocampuses. These structures, one in each cerebral hemisphere, are involved in the formation of long-term memories. Compared with the size of its brain, an elephant’s hippocampuses are about 40% larger than those of a human being, suggesting that the old proverb about an elephant never forgetting may have a grain of truth in it.

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