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In the world of noses, the elephant’s trunk clearly stands out for its size, flexibility, strength and slightly creepy gripping ability.
Go ahead, try to pluck a leaf with your nostrils and see how you fare. So perhaps it should come as no surprise that the elephant’s sense of smell is also outstanding.
Past studies have shown that elephants have more scent receptors than any other mammal. And in other experiments, researchers following up reports that elephants in Angola were avoiding minefields found that they could detect TNT.
Another report concluded that elephants could use scent clues to tell the difference between two Kenyan tribes, the Maasai, who traditionally speared them, and the Kamba, who did not. The elephants apparently used these clues to help them avoid the Maasai.
The latest bit of research adds to the evidence by showing how they use their great sense of smell in choosing food. Elephants often must find vegetation and water at a distance, and they also distinguish between fairly similar plants once they reach a clump of likely vegetation.
It seemed that they probably used their sense of smell, but Melissa Schmitt, a researcher at the University of KwaZulu-Natal in South Africa, and her colleagues wanted to see how good they were.
So she tested them at close range, using two buckets with two different hidden foods. They easily picked out the bucket with leaves from plants they enjoyed, say wild pear, and avoided ones they didn’t like, wild olive, for instance.
To test the elephants’ odor detection at longer range, the researchers built an elephant-sized version of a classic laboratory Y maze of the sort used to test lab mice.
In the elephant version, the animals easily chose the branch of the Y that led to the kind of plant they preferred. It might seem obvious that an animal can sniff out its food. Dr. Schmitt acknowledged that humans know when neighbors are grilling steak.
But, Dr. Schmitt said, the elephants are “doing this throughout their entire environment, across multiple spatial scales, for things that don’t smell very strongly, you know, relative to the steak on the barbecue.”
So it adds to the tale of the trunk. It can move logs and sniff under them. It can spray water on an elephant’s back, pluck a leaf, or reach into the wind for a hint of that special kind of mistletoe.
For that hard to reach treat, they don’t just pluck leaves, they knock down the trees on which the mistletoe grows. The trunk comes in handy for that task, too.