New research published in the journal BMC Evolutionary Biology finds that female cats adjust their response to suit kittens they perceive to be more distressed. They responded more quickly to high-arousal cries from upset kittens than cries from less stressed-out cats, whether or not they happened to be a mother themselves.
Evolutionary biologist Wiebke Konerding, who co-authored the paper, designed the adorably stressful study with the help of 17 adult cats and 16 kittens. First, she recorded sounds of kittens in low and high states of arousal. (To provoke a state of low arousal, kittens were separated from mother and siblings for three minutes; high arousal was achieved by adding extra handling — either lifting the kitten up or turning it onto its back — to the mix.) Then, she prepared the audio samples and played them to unrelated kitties in a testing room filled with a speaker and a cage.
After being habituated, cats were escorted into the facility, placed in the cage, and fed a solution of milk and water. “From behind we played the kitten call,” Konerding explains, “and so they turned around. We measured the reaction time to see how fast they would respond.”
Sixty-one percent of the time, the cats responded, stopping their drinking or turning their head toward the call. Though female cats did not differ in their responses based on whether they were already mothers, they did exhibit a key difference — they reacted ten percent more quickly to kittens with high-arousal calls than those in less distress. That suggests that female cats can adjust their response based on the emotional state of kittens.
For Konerding, that wasn’t much of a surprise — after all, cat moms nurse their young and teach them the ways of the world, and other species have been shown to adjust their behavior to the urgency of their children’s cries, too. But something did surprise her: The response of male cats.
Unlike some other species, male cats don’t care for their young. Rather, they get busy and get out, moving on to spawn as many kittens as possible. But in the experiment, the male cats responded to low-arousal kitten cries just as quickly as females. The only difference was that they didn't adjust their behavior based on kitten stress levels. “I was surprised that the males responded to the kitten calls at all,” says Konerding. “I thought that they might just ignore it because it has no relevance in their life.”
The findings suggest that perhaps female cats have evolved some kind of hearing mechanism that allows them to tune in more to their kittens — and that maternal care in cats may have affected the way that the animals evolve.
Now, researchers can focus in on whether cats care more about the emotions of their own kittens versus those who are unrelated. Konerding notes that the cats liked the experiment so much that they eventually started to run into the experiment room without being coaxed. “They knew what was happening and they knew about the milk,” she laughs. “They were sitting there waiting for the experiment to begin.” Regardless of how tuned in cats are to their younger colleagues, scientists shouldn’t have trouble recruiting participants for their next experiments.