LiveScience examines how and why rats are aroused by tiny vests:
In an unusual study, researchers allowed virgin male rats to have sex with females wearing special rodent “jackets.” Later, when scientists gave the males a chance to mate again, the animals preferred to mate with jacket-wearing female rats rather than with unclad ones.
The findings suggest that male animals can learn to associate the sight and feel of clothing with sex.
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In a second experiment, the researchers exposed virgin male rats first to jacketed females that were sexually receptive, then to unjacketed females that were not sexually receptive. Then they put the rats in a chamber similar to the first experiment, with one female wearing a jacket and one not wearing a jacket.
Again, the trained males preferred to mate with the jacketed females, mounted them more often and ejaculated more quickly, compared to with the unjacketed females.
Zunino and his colleagues also wanted to know how the jacket experience affected activity in the rats’ brains. Right after the male rats mated with the jacketed females, the researchers sacrificed the animals and injected a dye into their brains that shows the activity of a gene called c-fos, which is a measure of neural activation. Specifically, they looked at c-fos activity in the pleasure centers of the rats’ brains, including regions called the ventral tegmental area and the nucleus accumbens.
Males that mated with jacket-wearing females showed more c-fos activity in these brain areas than did males who mated with jacketless females, preliminary results showed.