Li Zhang has anesthetized a lot of mice in his research career.
Several years ago, the University of Southern California neuroscientist began noticing that sometimes, when he placed an anesthetized mouse back in its cage, its cage mate would start acting strangely, sniffing and biting around the unconscious mouse’s face. To Zhang, it almost seemed like the mouse was trying to revive its knocked-out partner with something like first aid.
Such behaviors have been anecdotally observed in other species, like elephants or dolphins who help incapacitated group members. While other mouse researchers have noticed similar behaviors toward unconscious mice, it’s never been closely studied, says Zhang.
Now, he and his colleagues show that unconscious mice elicit a suite of behaviors from cage mates that seem to speed recovery from anesthesia. Oxytocin neurons, which underlie helping behaviors in a range of species, help activate the revival-like behaviors in mice, researchers reported in the journal Science.
“To me, this looks very much like a behavior that’s driven by what I would call the altruistic impulse,” says James Burkett, a neuroscientist at the University of Toledo who wasn’t involved in the study. “We can’t infer just from our observations that these mice have an intention to help. We only know that they’re responding to an animal in need and they perform a behavior that does benefit them.”
Zhang and his colleagues studied this behavior by presenting a mouse with an unconscious cage mate and an active mouse. They found that the subject mouse spent much more time interacting with the unconscious cage mate, exhibiting a consistent set of behaviors that escalated over time.
First, the mouse would just sniff and groom its knocked-out cage mate. But as the mouse remained unresponsive, the subject mouse would start biting its partner’s mouth, and even pulling out its tongue.
Lab mice may give ‘first aid’ to unconscious mates
https://www.npr.org/2025/02/21/nx-s1-5305006/lab-mice-may-give-first-aid-to-unconscious-mates
There’s a wrinkle — or many — in the story behind an elephant’s trunk
https://www.npr.org/2024/10/11/nx-s1-5140599/elephant-trunk-wrinkles-brain-stem
Dolphins Recognize The Calls Of Long-Lost Friends
https://www.npr.org/2013/08/07/209462717/dolphins-recognize-the-calls-of-long-lost-friends
Reviving-like prosocial behavior in response to unconscious or dead conspecifics in rodents
https://www.science.org/doi/10.1126/science.adq2677