From the article: “This animal is the opportunity to think about and develop new techniques or potential targets for making new drugs, because their [reproductive] cells have the same program that we have in mice and humans, but they’re behaving differently,” says Miguel Angel Brieño-Enríquez at the University of Pittsburgh in Pennsylvania.

Native to East Africa, naked mole rats (Heterocephalus glaber) live for up to 37 years and form underground colonies with social structures similar to those of bees, including a single queen that produces offspring for her entire life. By contrast, mice only live for about four years and their fertility starts dropping when they are only 9 months old.

Curious about these differences in reproductive lifespans, Brieño-Enríquez and his colleagues looked at the ovaries of naked mole rats under a microscope when the animals were 1, 5, 8, 15, 28 and 90 days old. They used advanced staining and testing techniques to identify the different kinds of cells they saw. In particular, they were looking for germ cells that can divide and mature into oocytes – or eggs – through a process known as oogenesis.

In humans, mice and other mammals, oogenesis only occurs before birth and, in some species, shortly afterwards, leaving newborn females with a limited lifetime supply of eggs. Those eggs gradually die over time, leading to reduced fertility with age.

In the naked mole rats, though, Brieño-Enríquez and his colleagues found large numbers of germ cells at every stage of life they tested, with numbers steadily increasing throughout the first week of life. At 8 days old, the naked mole rats had an average of 1.5 million egg cells – 95 times more than 8-day-old mice, says Brieño-Enríquez.

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