NYT -- A new study in the journal Science has found that rats can be helpful -- the first instance that such behavior has been documented in rodents.
The researchers placed a free-roaming rat in an arena with a caged rat. Over the course of several days, the free rats realized they could nudge open a door and release the caged rat.
After figuring this out, they did so repeatedly, day after day.
The researchers placed a free-roaming rat in an arena with a caged rat. Over the course of several days, the free rats realized they could nudge open a door and release the caged rat.
After figuring this out, they did so repeatedly, day after day.
"They then did what we refer to as a celebration," said an author of the study, Peggy Mason, a neuroscientist at the University of Chicago. "The trapped rat runs around the arena, and the free rat appears excited and runs after the trapped rat."
That behavior alone is not enough to show that rats are empathetic, she said. The rats could be releasing their caged cohorts simply for companionship.
So the researchers changed the setup: when the free rat released the caged rat, the caged rat went into a second arena, and the two were unable to interact.
Still, the free rats released the caged rats, day after day.
Then the researchers placed a free rat in an arena with a caged rat and locked-away chocolate.
The free rats were just as likely to free the caged rat as they were to liberate the chocolate and eat it. Moreover, when they got the chocolate they almost always shared it; on average, they would leave about one and a half out of five pieces for the caged rats, Dr. Mason said.
There was also a difference in the behavior of male rats and female rats.
That behavior alone is not enough to show that rats are empathetic, she said. The rats could be releasing their caged cohorts simply for companionship.
So the researchers changed the setup: when the free rat released the caged rat, the caged rat went into a second arena, and the two were unable to interact.
Still, the free rats released the caged rats, day after day.
Then the researchers placed a free rat in an arena with a caged rat and locked-away chocolate.
The free rats were just as likely to free the caged rat as they were to liberate the chocolate and eat it. Moreover, when they got the chocolate they almost always shared it; on average, they would leave about one and a half out of five pieces for the caged rats, Dr. Mason said.
There was also a difference in the behavior of male rats and female rats.
"The females, once they open the door, they open the door every day, and within a few minutes," Dr. Mason said. "But the male rats would occasionally take off a day."
