Instead of civil war, naked mole rat colony peacefully replaced queens

When the Salk Institute for Biological Studies in San Diego acquired the first colony of naked mole rats in 2019, researchers named them “Amigos” (Spanish for “friends”).

The naked mole rat is an underground mammal native to East Africa. Since the 1960s, scientists have studied the unusual living conditions and long, healthy lifespans of captive colonies in laboratories and zoos.

The name of the Sauk Colony was prescient. Years later, they demonstrated a peaceful transition that defied conventional wisdom about how naked mole rat colonies replace queens, usually by all-out war.

“Maybe they heard us and were like, okay, let’s show them we’re friends,” says Shanes Abeywardena, a veterinarian and postdoctoral fellow in scientist Janelle Ayers’ lab. Abeywardena and her colleagues documented the nonviolent queen change in the April 15 issue of the journal Science Advances.

The study expands our understanding of how naked mole rats, whose secrets to longevity are often studied, can use different cooperative strategies to thrive. Unusual among rodents, they can live for over 30 years, despite having essentially no hair or fat and no ability to regulate their body temperature.

The colony arrived in San Diego in the summer of 2019, dispatched by fellow researchers from the City University of New York in a clear hierarchy.

“Queen Tere has established herself as a proper queen and matriarch,” Abeywardena said. She arrived with a male mate, whom researchers named Paquito, and the first of four surviving puppies.

Naked mole rat colonies often consist of one large mating queen and dozens of smaller male and female rats that perform specialized roles such as guarding, food gathering, and caregiving.

In a naked mole rat colony, the queen bee is the largest and the only colony that gives birth to babies. And Queen Tere went on to have even more.

colonial crisis

When the colony reached 39, there followed a year in which her babies died soon after birth, probably due to overcrowding.

Abeywardena and colleagues hypothesized that the naked mole rats adapted because they felt a strain on their resources, and perhaps because their newborns were poorly cared for. In 2021, researchers separated 20 naked mole rats to start another family called the Amici colony, and Queen Tere gave birth to several viable offspring.

Then came more confusion. A laboratory construction project forced the colony to relocate in 2022. “We had to move them to another facility because it was stressful for all of us, including the naked mole rats,” Abeywardena said. “During that time, we noticed that Tere’s fertility had stopped and she hadn’t bred for a year.”

At that point, Abeywardena and her colleagues believed that Queen Tere, who was no longer fertile, would be overthrown. “Will there be a violent war? Will there be an invasion?” she says, drawing on examples from zoos and scientific literature about how new queens emerge. “That’s what we expected, but it wasn’t.”

Instead, two of Tere’s daughters grew up and started having children.

a new queen takes the throne

One person died from internal injuries. However, the other queen, named Arwen, became the colony’s only queen born in 2025. “As things unfolded, we were just in complete shock,” Abeywardena said.

Even after Tere abdicated the throne, he continued to protect his colony, including the daughter of the crowned queen, without displaying the expected aggressive behavior.

Tere is active and is still the largest naked mole rat in the group, only 7 years old. Abeywardena says that what lies ahead could be a golden retirement of more than 20 years as the “queen grandmother of the colony”.

This seemingly unconventional peaceful transition has its benefits, too. “Aggressive, deadly queen warfare increases costs because there is a risk of injury. There is a risk of losing individuals, workers,” Abeywardena said. For naked mole rats, fighting a civil war requires energy and resources.

Regime change through civil war is more common in this species. In fact, while the amigos colony in San Diego was peacefully replacing its queen, the naked mole rat colony at the Smithsonian’s National Zoo in Washington, D.C., was undergoing a classic bloody coup.

The naked mole rat war has been going on off and on for more than two years. “After a couple of months, things finally seem to calm down, and then there’s going to be violence,” said Kenton Kearns, curator of the zoo’s small mammal pavilion. “Sometimes it’s just a low-level conflict, and other times it can be fatal, and it can quickly lead to fatal injuries.”

But the zoo’s previous colony was older and more benign, Kearns said. Some of the mole rats in that colony were over 20 years old and had multiple queens breeding side by side.

So the idea that the old and new queens could peacefully overlap is “very likely,” Kearns says. Although not considered standard, it may not be as rare as scientists previously thought.

Kearns says humans’ understanding of naked mole rats is constantly evolving. Some of the early assumptions made when studying animals in laboratories and zoos may have applied only to the specific groups studied.

Decades of observations have demonstrated that there is great diversity in the behavior and biology of individuals and colonies.

Kearns says naked mole rats flaunt all kinds of rules. Although they are mammals, they are mostly hairless, cold-blooded, extremely long-lived, and resistant to diseases such as cancer.

No wonder they rebel against society’s rules. And in time, scientists may discover that more naked mole rats are peace-loving than they thought.