Rodents cleared airways and licked the ‘casualty’ in the first scientific evidence of an emergency-like response
The Times
It appears that heroism is not reserved for humans. Scientists have discovered that when one rodent finds another lying unconscious, it does not simply scurry away: it leaps into action, attempting what can only be described as mouse-to-mouse resuscitation.
In a series of experiments, researchers observed mice apparently battling to revive stricken peers that had been drugged to knock them out.
They pawed at them, licked them, and pulled their tongues aside to clear their airways. The behaviour was not only effective but strikingly reminiscent of human first-aid protocols.
The study, published in the journal Science, involved placing one mouse under anaesthesia, rendering it temporarily unconscious. A “bystander” mouse was then introduced. In more than half of the cases, they pulled on the unconscious mouse’s tongue, enlarging their airway. When the incapacitated rodent had a small plastic ball placed in its mouth, its companion managed to extract the object 80 per cent of the time before continuing its life-saving routine.
“These behaviours are reminiscent of how humans are taught to clear the airway of an unconscious individual during CPR,” the researchers noted.
Large social mammals have previously been documented lending assistance to each other. Chimpanzees have been seen tending to wounded companions, dolphins are known to push distressed pod members to the surface to help them breathe, and elephants have been observed assisting their ailing relatives. Never before, however, has such a meticulous, paws-on approach to first aid been recorded in a creature as small as a mouse.
Huizhong Whit Tao, a neuroscientist at the University of Southern California and one of the study’s authors, told the American broadcaster NPR: “It seems that the mouse can perform, deliberately, this whole set of behaviours.”
The routine is thought to be instinctual, rather than learnt, as the mice had not seen an unconscious animal before. “This is the first time that we’ve reported these kinds of emergency-like responses from animals,” she added.
Rodents that received treatment regained consciousness and mobility more quickly than those that were left alone. The “carer” mice spent more time tending to their fallen peers if they had encountered them before, suggesting a level of social recognition in their actions.
Further experiments suggested that the behaviour is driven by the amygdala and hypothalamus, areas of the brain responsible for emotional responses in humans and which release oxytocin, sometimes dubbed the “love hormone”.
In a commentary published in Science, William Sheeran and Zoe Donaldson of the University of Colorado at Boulder said: “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.”