Submission + - Sperm Whales use Babysitters for Young
Hugh Pickens writes: "Every new mother knows how hard it can be to find a babysitter — especially when the baby weighs about a ton and drinks more than 40 gallons of milk a day. Although sperm whales have long been known to have the largest brain of any animal and are highly social creatures often singing duets when they are socializing, now biologists studying sperm whales in the North Atlantic have discovered that while some whale mothers are making hour-long dives more than 2000 ft below the ocean's surface searching for the squid they feed on the whales use the equivalent of a babysitting pool to ensure mothers can feed without allowing their young to be endangered by killer whales who prey on the youngsters. After spending two years following 23 sperm whale calves and their families through the Sargasso Sea around Bermuda and the Eastern Caribbean in a 40 foot research vessel, scientists found that females share responsibility for the younger members of a pod by establishing networks of caregivers. "Sperm whales are slow reproducers — 5 years is a pretty good calving interval — so that means every calf represents a huge investment for the mother," says Dr Luke Rendell, a marine biologist at St Andrews University. "It is not unreasonable to suggest that the need to protect vulnerable offspring could have been an important evolutionary driver of co-operation among sperm whales, just as it may have been in humans.""
