[Image of a rat society]

"Holding on to Rule" and "Transfer of Power" in Rat Societies: Scientists Uncover Strange Facts

Queen bees are perhaps the most famous of all in the animal and insect kingdoms, but a team of researchers in the United States discovered that a species of rat called the naked mole-rat (Heterocephalus glaber) lives in underground tunnels and is ruled by a single queen. She bears all the offspring and leads a complex society of other rats who obey her commands in managing the colony's affairs, providing food, and caring for the young.

When the queen's fertility declines or she dies, a bloody conflict may erupt between the mother queen and other females vying for leadership. The transfer of power can also occur smoothly between the mother queen and one of her assistants, especially during times of hardship or when a crisis threatens the safety of the colony.

[Image of a rat society] Naked mole-rats have attracted the attention of scientists since the 1960s. Researchers have concluded that this species, native to East Africa, may be one of the few mammals to live under a highly developed social structure, similar to some insects like bees and ants, which live in colonies with a strict hierarchical social order ruled by a single queen responsible for reproduction.

One of the reasons for the focus on these rats is their longevity, reaching up to thirty years, and their habit of living in dark, damp underground tunnels. They also appear to be less susceptible to certain diseases, such as infections and cancer. 

Scientists believe that this lifestyle allows them to maintain a stable existence, focusing their efforts on gathering food and resources, free from the conflicts that arise from mating disputes between males and from biological phenomena like infanticide found in other species. However, the growth of the colony depends solely on the queen's fertility and reproductive capacity.

Image of rats

In a study published in the journal Science Advances, researchers focused on the social structure of these rats and their resilience in times of danger. 

"Resilience is the ability of biological systems to recover and return to normal life after exposure to adversity, and it is of paramount importance to scientists in understanding the nature of disease and recovery in animals," said lead researcher Janelle Aries of the Salk Institute for Biological Research in the United States.

She added in comments to the science news website Bioscience: "While previous studies have focused on the cycle of conflict, this new research focuses on the idea of ​​cooperation and basic organization in animal societies."

 Rat Image  

Researcher Shanice Abeywarden, who co-authored the study, explained: "We have known for years that a single female in a naked mole-rat society is responsible for reproduction, and that the transfer of power occurs through bloody conflict between queens. However, this new study aimed to determine whether it is possible for more than one queen to coexist peacefully."

The research team observed a colony of naked mole-rats for six years to understand the advantages and disadvantages of the complex social structure these mammals lead. During the first year, the researchers ensured a stable environment for the colony with a single queen in the laboratory.

In the next phase of the experiment, the researchers introduced a series of environmental challenges to the colony, such as increasing the population or relocating it to new locations. These factors typically affect the reproductive capacity of rats in general. The researchers found that when the colony's population increased,

the queen continued to reproduce, but the survival rate of the young declined significantly. However, the queen remained the sole source of reproduction in the group. When the researchers changed the colony's location, the queen ceased reproduction entirely, triggering the succession process to establish a new queen.

During the following year, the researchers observed a second female in the colony slowly emerging as a potential successor. But surprisingly, the original queen and the new heir developed a cooperative relationship, even experiencing simultaneous pregnancies to help the colony weather the crisis. 

When the new queen fully assumed power, the original queen peacefully retreated to the plebeians, assuming a non-reproductive role within the colony—a gradual and peaceful transfer of power from one queen to another.

"This study has shed light on a hidden aspect of reproductive organization in naked mole-rat colonies, opening up a new avenue of research for this mammalian species," says biologist Alexandria Schreibman in an interview with Popular Science.

Researchers believe that studying the peaceful transfer of power in the mole-rat society is an important step towards understanding how they adapt to environmental changes, as they are rare mammals that live under a complex social organization. 

Through future studies, they aim to identify the environmental factors or social influences behind the decision and nature of the transfer of power from one queen to another within the same colony.