List an elephant’s most iconic characteristics and tusks should be right behind the long trunk, and arguably ahead of big ears and thick skin.
Tusks are elongated teeth that grow continuously and are used to dig for food and nutrients, clear paths through vegetation, mark or remove tree bark, and for fighting between males. The tusk can serve those diverse purposes thanks to the properties of its main material, ivory, which makes it strong and tough.
Ivory’s impressive properties make it attractive to humans. Traditionally used to make art and ornaments of cultural value, ivory has become a valuable status symbol. But as studies have shown, demand for ivory has helped to fuel a multibillion-dollar wildlife trade that encourages illegal hunting. And now new research has found that this may also have left an evolutionary mark on elephants.
A study by biologists at Princeton University looked at African savannah elephants in Mozambique’s Gorongosa National Park. During a civil war that lasted from 1977 to 1992, more than 90 per cent of large herbivores were slaughtered, including elephants. The elephant population dropped from more than 2,500 individuals 50 years ago, to less than 250 in 2000.
この記事は BBC Focus - Science & Technology の December 2021 版に掲載されています。
7 日間の Magzter GOLD 無料トライアルを開始して、何千もの厳選されたプレミアム ストーリー、9,000 以上の雑誌や新聞にアクセスしてください。
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この記事は BBC Focus - Science & Technology の December 2021 版に掲載されています。
7 日間の Magzter GOLD 無料トライアルを開始して、何千もの厳選されたプレミアム ストーリー、9,000 以上の雑誌や新聞にアクセスしてください。
すでに購読者です? サインイン
COULD MARINE CLOUD BRIGHTENING HELP US FIGHT CLIMATE CHANGE?
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IS IT SAFE TO RUN EVERY DAY, OR SHOULD I DITCH MY RUN STREAK TO SAVE MY KNEES?
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WHAT MAKES THE MEDITERRANEAN DIET SO GOOD FOR US?
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WHAT IS MEXICO'S BLUE HOLE?
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HOW CAN I TELL IF I'VE GOT HIGH CORTISOL LEVELS?
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THE LUNGFISH
In 1836, European scientists discovered a peculiar animal from the River Amazon that they struggled to identify. Its eel-like body was a few feet long and its air-filled lungs persuaded anatomists it must be a reptile.
ARE WE THE ONLY SPECIES TO HAVE BEEN THROUGH A STONE AGE?
The Stone Age might conjure up images of early humans, sitting around a campfire or hunting prehistoric beasts, but evidence shows that we're not the only species that has learned how to work with stone tools. Wild chimpanzees (Pan troglodytes) use stone tools to crack open nuts.
Should we scrap daylight saving time?
Most of us look forward to the extra hour we get in bed every October, but researchers argue that changing the clocks twice a year harms our health
THE INTERNET OF ANIMALS
SCIENTISTS ARE USING ELECTRONIC TAGS AND SATELLITES TO TRACK WILD ANIMALS AND CREATE A DATA NETWORK THAT COULD HELP US ADDRESS THE BIODIVERSITY CRISIS
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