And according to a new study from Japan, naked-mole-rat queens use their hormone-rich poop to govern their subordinates. When the subordinates eat the hormone, it turns them into attentive caretakers of the queen’s own pups. It’s mind control, via poop.
Naked mole rats had interested Kazutaka Mogi, a biologist at Azabu University, because of their unusual social structure. Like ants and bees, but unlike almost all other mammals, naked mole rats live in large colonies where the queen is the only female that reproduces. Her subordinates take care of the pups, and they never make sex hormones of their own or become sexually mature. Mogi and his team had investigated parenting in mice, and they knew that hormones play a key role in triggering parental behaviors in mammals. If the bodies of the subordinate naked mole rats aren’t making any hormones, how do they become such attentive caretakers—to pups that aren’t even their own?
The team collected fecal pellets from pregnant queens and gave them to a handful of subordinate females, which soon became much more responsive to the cries of pups. Then they repeated the experiment to make sure the hormones were really the key component of the poop. This time, they took fecal pellets from nonpregnant queens and added estradiol—a type of estrogen—to only half of the pellets. Only the naked mole rats that ate the estradiol-supplement poop became more responsive to pup cries.
Mogi was excited. He had never seen hormones work like this before. Hormones are powerful mediators of behavior, but their effects are normally limited to the body of the animal making them. Here the queen seems to be making hormones to alter the bodies of totally separate animals. Insect colonies have sometimes been called superorganisms for the way thousands of individuals behave as one unit; in this case, hormones seem to be acting on naked-mole-rat colonies as a single superorganism.This is pretty amazing stuff that I would not have expected in mammals.