Sperm whales are the biggest animals on Earth that have teeth. They are carnivores, which means they eat meat. Although sperm whales can be found in all oceans, they prefer the waters with high squid populations, which are their main diet. A sperm whale can eat up to 1,500 kg of food each day. Sperm whales are big animals. The males can grow up to 18 metres long and weigh up to 54,000 kg while the females are a bit smaller with a length of 12 metres and a weight of 17,000 kg. A female sperm whale gives birth to one calf every five to seven years after a gestation period of fourteen to nineteen months. The life span of sperm whales can be up to sixty or seventy years. It is interesting to know that they also have the largest brain of any mammals. Sperm whale populations are at risk due to hunting and their accidental entrapment in fishing nets.