Mice Display Remarkable Altruism, Attempting to Revive unconscious Companions
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New research reveals that mice exhibit a surprising capacity for empathy and proactive care, intervening to help unconscious peers – even attempting to clear their airways – suggesting the roots of altruistic behavior may run deeper than previously understood.
What would you do if you encountered an unconscious person? Instinct dictates calling for help, administering aid, and ensuring they can breathe. But what about other species? Do animals demonstrate similar concern for incapacitated members of their community? Increasingly, the answer appears to be yes. Observations of chimpanzees tending to fallen companions,elephants assisting sick relatives,and dolphins supporting distressed pod-mates hint at a complex emotional life in the animal kingdom. Now, a groundbreaking study published in Sci. Adv. in 2025 has revealed that even mice display this “emergency response,” actively attempting to revive unconscious individuals.
A Curious Observation Sparks Scientific Inquiry
The investigation began with Zhang, a brain researcher at the University of Southern California, noticing unusual behavior in his lab.After returning a rat from anesthesia to its cage, the animal’s cage-mate promptly approached, sniffed, and began exhibiting peculiar actions – licking the recovering rat’s eyes and gently attempting to bite around its mouth. Repeated observations of this behavior prompted Zhang and his team to ask a fundamental question: Do mice react differently to unconscious peers?
Researchers meticulously designed an experiment,placing anesthetized mice in cages with active,awake mice and then observing the interactions over a 13-minute period. The results were striking. Mice devoted nearly half of their time to interacting with the unconscious mouse, touching and biting it, a stark contrast to the less than six percent of time spent with an active cage-mate.
Beyond Curiosity: Active Intervention
The actions weren’t merely inquisitive. As described by one researcher to New Scientist, the mice “started by smelling, then moved on to cleaning her scalp, and then performed very intense physical actions.” Most notably, the mice repeatedly opened the unconscious mouse’s mouth and attempted to retract its tongue. This tongue retraction occurred in over half of the cases involving an anesthetized mouse, a behavior never observed with awake or sleeping mice.Eye licking and biting in the mouth area were also exclusively directed towards unconscious individuals.
Interestingly,the intensity of this behavior correlated with familiarity. Mice were more likely to engage in biting and tongue-pulling with cage-mates they knew.
To understand this behavior, researchers examined brain activity. They discovered that encountering an unconscious mouse triggered a surge in oxytocin – a neurotransmitter associated with social bonding – in the hypothalamus. When they blocked oxytocin release, the mice exhibited less grooming, licking, and biting. Conversely, artificially stimulating oxytocin release increased interaction with the unconscious mouse, particularly in unfamiliar individuals.
Further research, conducted by researchers at the University of California, revealed that neurons in the amygdala – a brain region involved in emotional responses and social behavior – also play a crucial role in recognizing and responding to an unconscious mouse. Activating thes neurons increased the treatment response, while suppressing their activity diminished it.
An accompanying article explained that oxytocin-secreting neurons in the hypothalamus project to the amygdala, influencing its activity and ultimately driving the observed behavior.
The hormone oxytocin’s involvement in social relationships extends beyond mice, appearing in many species, including humans. This shared mechanism suggests that similar behaviors might potentially be present in other animals. Indeed, rats are known to help free trapped cage-mates, and many species share food – extending the possibility that providing first aid could be another expression of this inherent social concern.
A chimpanzee helps her friend who fell from the top of a tree image: Shimada, M.,yano,W., Sci. Rep. 13, 16661 (2023), CC BY 4.0
This research offers a compelling glimpse into the complex emotional lives of animals and suggests that the capacity for empathy and altruistic behavior might potentially be deeply ingrained in the mammalian brain.
