For six years, a team at the Salk Institute watched a colony of naked mole rats navigate an unexpected crisis — and what they witnessed turned decades of scientific assumption on its head. When a reigning queen's fertility failed after environmental stress, subordinate females did not tear the colony apart in violent power struggles. Instead, they cooperated. One subordinate slowly rose to take the crown, and the old queen stepped aside. The kingdom changed hands peacefully.
The finding, published in Science Advances, upends the long-held belief that naked mole rat succession is always violent. "For years we've known that only one female, the queen, reproduces, and that queen succession occurs through violent queen wars," said co-first author Shanes Abeywardena, a postdoctoral researcher at Salk. "We wanted to see if multiple queens could peacefully exist." Now, it seems, they can.
Naked mole rats have fascinated scientists since the 1960s, when researchers first brought the peculiar, nearly hairless rodents into labs. A decade later, they became the first mammals identified as eusocial — living, like ants and bees, in colonies with strict hierarchies and a single child-rearing queen. One female bears all the young; everyone else tunnels, forages, and tends to newborns. The system keeps resources pooled and conflict minimal — but it also means the colony's survival hinges entirely on one fertile body.
To test whether naked mole rats might have evolved a backup plan, the Salk team started with a healthy, reproducing colony and then introduced two stressors known to destabilize reproduction in rodents: increased colony density, followed by relocation to a new facility. After the density increase, the queen could still conceive, but pups died young. Then, after the move, her fertility collapsed entirely. That is when the peaceable transition began.
Over the following year, a subordinate female ascended without the violent pitched battles scientists had come to expect. The researchers observed cooperative behavior between the old queen and her successor — a finding that points to resilience as a core feature of these unusual societies. "While much research focuses on conflict, my lab studies cooperation as a fundamental organizing principle," said senior author Janelle Ayres, a professor at the Salk Institute and Howard Hughes Medical Institute Investigator.
Naked mole rats are already known for extraordinary traits: they live more than 30 years, feel no inflammatory pain, and resist cancer. This study adds a new dimension — social resilience, the capacity to recover and adapt after stress. For a species that rules underground kingdoms in the tunnels of sub-Saharan Africa, that flexibility may be exactly what keeps the colony thriving when circumstances change.