According to a study published in the journal Science, mice innately aid other mice when they fall unconscious. Humans, elephants, chimps, and dolphins all recognize when a companion requires life-saving assistance, but this behavior has not been seen before in mice.
In the study, mice began grooming the faces of anesthetized mice, pulling at or biting the tongues of their lifeless comrades. When a ball was placed in the mouth of the "patient," the bystander mouse removed the ball 80% of the time, clearing the airway as humans are taught to do in CPR class. The mice rarely exhibited face-grooming behavior with conscious mice or mice experiencing non-anesthetized sleep. Mice who received aid from their companions woke more quickly than mice who were left alone.
The study found that neurons in two areas of the brain showed different patterns when mice encountered an incapacitated mouse. In addition, inhibiting or activating these areas changed how the mice responded to a mouse requiring aid. As to why two different regions of the brain contribute to the behavior, the authors theorize that the release of oxytocin might improve information processing in the amygdala, enhancing their response to a life-threatening situation.
People who witness someone collapse and who subsequently perform cardiopulmonary resuscitation (CPR) report that they intervene because they intuitively understand that the person would otherwise die (1). Humans are not alone in this instinct. Animals as diverse as elephants [Loxodonta africana and Loxodonta cyclotis (2)], chimpanzees [Pan troglodytes (3)], and dolphins [Tursiops truncatus (4)] can recognize and intervene by touching, nudging, and even carrying an incapacitated individual. On pages 843 and 842 of this issue, Sun et al. (5) and Sun et al. (6), respectively, provide information on the neurobiology underlying this impulse. They report that mice (Mus musculus) have an instinct to revive an unresponsive mouse and identify two distinct brain regions that are crucial for this behavior. These findings add to the evidence that an impulse to help others in states of extreme distress is shared by many species and highlight neural mechanisms that drive instinctive rescue.
Previously: MouseGoggles are tiny VR headset for mice
