No coup, just cuddles. A naked mole rat colony changes queens peacefully : NPR

When the Salk Institute for Biological Studies in San Diego got its first naked mole rat colony in 2019, researchers named them “amigos” — Spanish for “friends.”

Naked mole rats are subterranean mammals native to East Africa. Since the 1960s, scientists have studied captive colonies in laboratories and zoos for their unusual living arrangements and their long, healthy lives.

The name of the Salk colony was Prescient. A few years later, they demonstrated a peaceful transformation that overturns the conventional wisdom about how naked mole rat colonies replace queens – which is usually through all-out warfare.

“Maybe they heard us and they said, OK, we’ll show you that we’re friends,” says Shanes Abeywardena, a veterinarian and postdoctoral fellow in the laboratory of scientist Janelle Ayers. Abeywardena and his colleagues documented the queens’ nonviolent transformation for the April 15 issue of the journal Science Advances.

The study broadens the understanding of how naked mole rats, often researched for the secrets of their longevity, can use a variety of cooperative strategies to thrive. Unusually for rodents, despite having basically no hair or fat and lacking the ability to thermoregulate, they can live for over thirty years.

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

“Queen Terre established herself as the original queen and matriarch,” says Abeywardena. She arrived with her male partner, whom researchers named Paquito, and her first child of four surviving puppies.

Naked mole rat colonies are often structured with a large mated queen and dozens of smaller male and female rats that perform specialized roles such as protection, food gathering, and caregiving.

In colonies of naked mole rats, the queen is the eldest and the only one to have babies. And Queen Tere kept getting more.

crisis in the colony

When the colony reached 39, there was one full year in which its babies died soon after birth, possibly due to overcrowding.

Abeywardena and colleagues speculated that naked mole rats felt strain in their resources and perhaps adjusted to the poor care of newborns. In 2021, researchers divided 20 naked mole rats to start a separate family, which they called Amici Colony, and Queen Terre gave birth to a few viable babies.

Then came another disruption: a laboratory construction project forced the colony to move to 2022. “To the stress we all had, including the naked mole rats, we had to move them to a separate facility,” says Abeywardena, “During that time, we noticed Terre’s reproductive abilities shut down and she was not reproducing for a year.”

At the time, Abeywardena and his colleagues thought that Queen Terre, who was no longer reproducing viable, would be overthrown. “Is there going to be a violent war? Is there going to be aggression?” She draws on examples from zoos and scientific literature to explain how new queens typically emerge. “That’s what we were hoping for – but that’s not what happened.”

Instead, Terre’s two daughters began to grow up and have children.

A new queen rises

One died from internal injuries. But the other, named Arwen, becomes the colony’s only child-bearing queen in 2025. “As soon as this was revealed, we were completely shocked,” says Abeywardena.

Instead of showing the expected aggressive behavior, Terre continued to protect and defend the colony – including his emerging queen daughter – as he abdicated the throne.

Terre is playful, still the largest naked mole rat in the group, and is only seven years old. Abeywardena says she may have more than twenty golden years in her retirement as “Queen Grandmother of the Colony”.

This seemingly unusual peaceful infection has advantages: “The costs go up in those aggressive lethal queen wars because you risk injury. You risk losing individuals, i.e. workers,” Abeywardena says. For naked mole rats, waging a civil war requires energy and resources.

Regime change through civil war is more commonly seen in the species. Indeed, while the Amigos colony in San Diego was peacefully replacing queens, the naked mole rat colony at the Smithsonian’s National Zoo in Washington DC was carrying out a classic bloody coup.

That naked mole rat war has been going on, intermittently, for more than two years. “We’d go two or three months where it would seem like, finally, things were calming down and then — violence,” says Kenton Kerns, curator of the zoo’s small mammal house.

But the zoo’s previous colony was older and quieter, Kerns says. Some of the shrew rats in that colony were over twenty years old and several queens were breeding together.

So the idea of ​​the old and new queens peacefully overlapping is “very possible”, says Kerns, and although it is not considered the norm, it may not be as rare as scientists previously thought.

Kerns says human understanding of naked mole rats continues to evolve. Some assumptions from the early days of studies in laboratories and zoos may apply only to specific groups under study.

Decades of observation show that there is great diversity in behavior and biology among individuals and colonies.

Kerns says naked mole rats flout all kinds of rules. They are mammals but are mostly hairless and cold-blooded, they live very long and they are resistant to diseases such as cancer.

It makes sense that they would break social rules, too – and over time, scientists may discover that naked mole rats are more peace-loving than they thought.