The whales do most of their feeding during the summer months, too, when they are in chilly northern seas. This enables them to lay down fat reserves for their long journey south. What’s more, once the calves are born, they can drink up to a staggering 300 gallons of their mothers’ milk each day. The milk is a hefty 53 percent fat; human milk, on the other hand, is just 3 to 5 percent fat.
One of the most astonishing things about these gargantuan animals, though, is the huge distances that their annual migrations take them. The eastern Pacific gray whales, for example, travel all the way south from the cold waters of the far northern Pacific to the warmer climes off the Californian and Mexican coasts. After the winter, they subsequently swim back to the Arctic region. This can mean that they’ve made a round trip of around 12,000 miles.