Menopause is a rare trait among Earth's species, known to exist in only a few. Humans are one. Killer whales and four other toothed whales are the others.
New research examines menopause in these whales, with findings that may help explain why this phenomenon evolved, given that it is known in just six of the 6,000-plus mammal species living today. It might be titled: the tale of the helpful grandma whale.
The scientists compared the lifespans of 32 toothed whale species. They found that in the five menopausal species - killer whales, false killer whales, beluga whales, narwhals and short-finned pilot whales - the females live about four decades longer than the females of non-menopausal species of similar size.
