The giraffe is the tallest mammal in the world. Their large eyes, long tongue, sizeable ears. A giraffe has a height of 4.8 to 5.5 metres (16-18 feet) and weigh up to 900 kilograms. Although a giraffe’s neck is 1.5 – 1.8 meters but giraffes can walk swiftly and they run swiftly, as well. They only spend between 10 minutes and two hours asleep per day. They have a life expectancy of 20-30 years. The tallest mammal in the world is giraffe.