Elephants are the biggest land animals today. They communicate with each other using very low sounds. Most of these sounds are too low for humans to hear. But elephants can hear them from far away. There are three species of elephants: African Savanna (Bush), African Forest and Asian. The ears of African elephants are much larger than their cousins, whereas the ears of Asian elephants are shaped like the Indian subcontinent. There's also a trunk difference - African elephants have two 'fingers' at the tip of their trunks, whereas Asian elephants have one. The African Savanna (Bush) elephant is the world's largest land animal – with adult males, or bull elephants, standing up to 3m high and weighing up to 6,000 kg. Males only reach their full size at the age of 35-40 - that's well over half of their lifespan as wild elephants can live for up to 60-70 years. Elephant tusks are actually their teeth which first appear when elephants are around 2 years old. Tusks continue growing throughout their lives. Tusks are used to help with feeding or as a defense when fighting. Tusks are essential for elephants and are used for a variety of tasks, including digging for water and salt, lifting objects, and for defense and competition for males. But these beautiful tusks often cause elephants danger. They're made from ivory; a much desired object. An elephant's skin is 2.5 cm thick in most places. The folds and wrinkles in their skin can retain up to 10 times more water than flat skin does, which helps to cool them down. They keep their skin clean and protect themselves from sunburn by taking regular dust and mud baths.