Have you ever heard of the naked mole-rat? These peculiar creatures are some of the strangest mammals on the planet - and for good reason. Not only do they live longer than any other rodent, up to 37 years, but they can also have babies well into old age. While most female mammals experience a finite number of egg cells and become less fertile with age, naked mole-rats seem to be eternally fertile. But how do they do it?
A recent study has shed light on the remarkable rodents' secret: they never run out of egg cells. It turns out that naked mole-rat females produce an exceptionally large number of egg cells relative to their body size as pups and continue to replenish their ovarian reserve throughout their lives. This discovery challenges the belief that mammals have a limited reserve of egg cells established before or shortly after birth, which is not replenished thereafter. The researchers found that naked mole-rats are born without egg cells but produce them in abundance from a young age. Signs of egg cell production were even spotted in individuals up to 10 years old!
The scientists, whose study was published in Nature Communications, believe these findings could lead to new therapies for humans since menopause still happens at the same age even though humans are living longer. By studying the naked mole-rat's ability to maintain fertility throughout its life, researchers hope to protect ovary function later in life and prolong fertility. But the naked mole-rat's remarkable capabilities don't stop there! These hairless, burrowing creatures don't experience a drop in fertility as they get older, unlike most other mammals. They almost never get cancer, don't feel pain like other mammals, live in underground colonies, and only the queen can have babies.
To find out more about how subordinate females transition into queens when the dominant female is displaced or dies, scientists removed non-breeding females from colonies. In their absence, precursor egg cells in their ovaries started dividing—a sign of these females becoming reproductively active. So next time you come across a naked mole-rat factoid or two (or ten), remember just how extraordinary these creatures truly are!