Air from the rooms of the hungry or well-fed rats was pumped into the chamber of the focal rat. They found that the focal rats were much quicker to provide help -- by pulling a food tray within reaching distance of another rat -- when the air was pumped from a hungry rat's room. It took 16 focal rats an average of 29 seconds to provide help for hungry rats, compared to an average of 85 seconds to give help to the well-fed. - Good rat citizens -These might result from recently ingested food sources, the metabolic processes involved in digestion, or possibly even a pheromone that indicates hunger. Taken together, these signals form a "smell of hunger" for rats that serves as a reliable cue of need, said Schneeberger.
Source: Bangkok Post March 24, 2020 19:52 UTC