The Richest Milk on Earth

Harp seal mothers produce the fattiest milk of any mammal: approximately 50% fat. For comparison, whole cow's milk is about 3.5% fat.

This ultra-rich milk serves a critical purpose. Harp seal pups are born on Arctic ice floes, an environment that will only support them for a short time. The ice melts, predators lurk, and conditions are brutal. Speed is essential.

Thanks to this incredibly caloric milk, pups can: - Gain about 5 pounds per day (2.2 kg) - Triple their birth weight in just 12 days - Develop a thick blubber layer for insulation

The nursing period is astonishingly short: only 12 days. After this, the mother abandons the pup and returns to the sea to feed (she doesn't eat while nursing). The pup, now called a "beater" due to its tendency to slap the ice with its flippers, must survive on its fat reserves until it learns to hunt.

The mother's milk production is equally impressive. She loses about 7 pounds per day while nursing, drawing on her own blubber reserves. This makes nursing harp seal pups extremely costly — mothers may lose up to 80 pounds during the nursing period.