"Elephant is a herbivore animal and eat all almost all of the vegetation and fruits. They have almost hairless skin, wide ears, four legs, and long trunk. Elephants is known as the largest mammals. The elephants also have very sharp auditory because they have big and wide ears. By these ears, they can hear sounds from a distance about tens kilometer. At the back of the ears, they have one of the softest parts of their body which is called the knuckle. In a zoo, Mahouts (elephant trainers) use their feet to steer or give commands to the animal via the knuckle. Now, they are a kind of protected animals because their population remains little in their habitat. Their population began to decline year by year.

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What is knuckle?