It is, perhaps, the most extraordinary animal on the face of the Earth. Not only because of its strange and striking appearance: it is wrinkled, pink, almost hairless, with disproportionate teeth protruding from its snout and tiny, almost useless eyes. But it is extraordinary, above all, because of what it hides beneath that wrinkled skin.
The naked mole-rat (Heterocephalus glaber) is a mouse-sized rodent that lives in underground colonies in the Horn of Africa and also in laboratories around the world due to its fascinating qualities: it lives up to 30 or even 40 years, 10 times longer than its relatives, the mice. It rarely develops cancer. Its skin is insensitive to acids and it feels no pain. And it is the only mammal that lives in underground colonies, like ants, with a queen, and soldiers and workers that live to serve her.
The naked mole-rat has inspired cartoon characters and even comics. And on Wednesday, a study published in the journal Science Advances added another chapter to its legend: when the queen of the colony loses power, her subjects don’t kill each other to replace her. They can do something far more surprising. They can wait.
The story begins in July 2019 at the Salk Institute for Biological Studies in La Jolla, California. A colony of six animals arrived at Janelle Ayres’s lab: a queen of unknown age named Teré, a male named Paquito, and their first litter. The colony was named “Los Amigos.” The offspring were also given names, some taken from J. R. R. Tolkien’s Lord of the Rings, such as Arwen, the beautiful elf whose destiny is intertwined with that of the human Aragorn. Ayres, the study’s lead researcher, explains that naming the individuals makes tracking them over time easier, and reflects “a respectful acknowledgment of their individuality, without sacrificing scientific objectivity.”
For the first few months, Teré behaved like a model queen. She produced litters regularly, at intervals of 76 to 81 days, with six to 10 pups each, and a 100% survival rate. There was no aggression in the colony. The social structure was clear. But naked mole-rat colonies are living systems, and scientists wanted to know what happens when something unexpected occurs within that system.
In the world of the naked mole-rat, reproduction is a one-woman affair. Colonies are organized around this single breeding female, the queen, who monopolizes the rearing process. The queen actively suppresses ovulation in subordinate females through intimidation (biting or pushing them), chemical signals, and possibly physiological mechanisms that are not yet fully understood. It is a biological dictatorship.
What was known until now is that when the queen dies or disappears, the order violently breaks down. Subordinate females compete to assume the reproductive role, leading to a lot of aggression and continuous wars for succession: blood decides who rules.
But Ayres and his team suspected there might be another way. To find out, they needed a long experiment (it took six years), patience, and a colony they knew animal by animal. Los Amigos were perfect.
The researchers subjected the colony to two types of stress, both known to disrupt reproduction in rodents. The first was overcrowding. When the colony reached 39 animals, the queen continued to become pregnant and give birth to normal-sized litters, but all the pups died. The stress affected the newborns, not Teré’s fertility. And no subordinate took advantage of the queen’s reproductive weakness to try to usurp her throne.
The second disturbance was more powerful: a move. In May 2022, the entire colony was relocated to another building on the same campus. The environmental conditions — temperature, humidity, light cycle — were identical. But something changed. Teré’s reproductive capacity stopped completely. For the next year, she maintained a stable weight, and clinical examinations revealed no evidence of pregnancy. A year without offspring, with no apparent explanation. And again, no aggression.
It was during this long pause that researchers began to notice something new: in the fall of 2023, Teré tentatively resumed breeding with litters of one or two pups that didn’t survive. But, meanwhile, one of her daughters, Alexandria, began to show signs of pregnancy. A second breeding female had emerged in the colony, something that hadn’t been documented before. And without anyone fighting over the role.
This parallel reproduction occurred without any aggression, dominance challenges, or social instability in the colony. Teré and Alexandria were, in their own way, sharing the throne. Alexandria died shortly afterward, but another of Teré’s daughters from the same litter, Arwen, began to show the same signs of pregnancy. In October 2025, Arwen gave birth to two pups that survived — the first to do so since 2023. Researchers documented that Teré displayed “guarding” behavior toward Arwen and her litter, without any signs of conflict. The succession was complete — without violence or bloodshed. The queen mother relinquished power to her daughter, and she took it without any need to seize it.
Ayres is cautious about how much this finding reflects what happens in nature. “Our findings show that naked mole-rats are capable of peaceful succession, in addition to the more widely recognized aggressive pathway,” she says. “However, it remains to be determined whether this alternative strategy is used in natural environments.”
What the study does confirm is the existence of this flexibility, this “hidden path,” as the authors themselves call it. The findings reveal a “social plasticity,” they say, that had never been observed in this animal, traditionally subject to the queen’s strict hierarchy.
What determines which path a colony takes? Ayres has a hypothesis: “It is reasonable to speculate that succession depends not only on social stability and reproductive competition, but also on a cost-benefit analysis. When the cost of conflict is too high, a peaceful transition may be favored.”
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