Mice produce lactones which act like catnip on cats

Professor Benjamin Hart from the University of California’s School of Veterinary Medicine claims that mice produce lactones which act like catnip on domestic cats and, in doing so, it acts as a defence against being killed by said cats! Catnip contains a molecule called nepetalactone. You can see the connection in terms of chemistry.

Mouse and cat
Cat ponders on mouse’s presence. Photo in public domain
Two useful tags. Click either to see the articles: Toxic to cats | Dangers to cats


If this is true then it has very little impact upon my cat’s insatiable desire to attack and eat mice in the area where I live. In fact, it has zero effect on him because I have watched him dispatch mice inside my home and he does not without compunction. There is no pause to think about whether he’s going to bite down on a terrified, screaming mouse that he has recently caught from a neighbour’s property.

So, I don’t know what is going on with respect to this research. Is it true? It is said that mice have evolved as per Charles Darwin’s theory of evolution to have the ability to create lactones to bemuse and befuddle cats who are about to kill them.

It’s meant to have a similar effect to catnip and it lasts about 15 minutes giving mice a window of opportunity to escape. The lactones are in the sweat of mice according to this theory. We know what catnip does to cats: it causes an effect which is similar to that caused by a recreational drug in people. Although not all cats respond in the same way; apparently about 30% do not respond to catnip. Wild cats also respond to catnip in a similar way including the big cats.

Perhaps my cat is one of those but I don’t think he is because when I put real catnip on a scratching post or scratching board, he picks up the smell and behaves in a typical domestic cat manner, rolling around in it.

In earlier research it was found that mice are able to lose their fear of cats if they have been infected with the parasite Toxoplasma gondii. It is said that the infection causes irreversible brain changes. The research found that mice no longer react fearfully in response to the smell of cat urine which has been used to mark territory.

As mentioned above, it is suggested that the ability of a mouse to do this is an evolutionary development but this seems wrong for this reason. Cats respond to catnip which contains a similar or the same chemical. This too must be an evolutionary development. If that is the case then evolution has interfered with the natural predation of the cat against the mouse. It works against the cat’s interests which is not how evolution works. Evolution improves an animal’s survival rather than presenting a barrier to it. I can’t believe, therefore, that this theory holds water.


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