The African Elephant is the largest animal walking the earth, weighing up to 12,000 pounds (5.4 metric tonnes) and measure 24 feet (7.3 m), which is comparable to the size of a newborn blue whale. Pregnant blue whales gestate for a year before they give birth to the world’s largest offspring. Weighing 5,000-6,000 pounds (2,267 to 2,722 kg) and measuring approximately 23 feet (7 m), a blue whale calf immediately begins aggressively gaining weight. Consuming a staggering 50 gallons (200 liters) of milk per day from its mother, a blue whale calf can gain 250 pounds a day, averaging more than 10 pounds per hour in weight gain. The calf will continue to feed for at least six months and by the time the calf is a year old, he is able to feed on his own.