Ah, the classic example of predator versus prey — the cat and mouse. Not only are their stressful encounters played out in cartoons like Tom and Jerry, they’ve also inspired scientists who use cat exposures to stress rodents in the lab.

Finally, it seems as if a single-celled parasite called Toxoplasma gondii can give cats the upper hand in this cat-and-mouse game.


Mice get infected by ingesting anything contaminated with oocysts (eggs from T. gondii), which can then penetrate the rodent’s nervous system and create cysts within its neurons. These cysts can remain in the mouse for its whole life!

As you can imagine, this does not end well for the mouse, who will likely get devoured by a new cat.

Interestingly, even after T. gondii is cleared from mice, they continue to have no aversion to cats, suggesting a permanent change in their innate behavioural response to cats.


Written and illustrated by Catherine Lau. Catherine is a graduate student studying science communication at Laurentian University (Canada) with a research background in behavioural neuroscience (MSc). She considers herself an artist/scientist who is trying to merge both art and science together in hopes of better communicating science. Follow her on Twitter: @cat_lauscats