Why cat hiccups dilates the eye's pupil

Cats' eyes dilate when they hiccup. pic.twitter.com/9eAQ5h06iQ

— Science is Amazing (@AMAZlNGSCIENCE) November 19, 2020

This is an embedded video and sometimes they stop working overtime. If that has happened I apologise but I have no control over it.

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This is an interesting little video which repeats itself. I am sure that it has been all over the Internet. However, I have just spotted it. The cat hiccups and immediately afterwards the pupil of the cat's eye opens slightly because the muscles of the iris relax. That is my theory. The pupil of the cat's eye is made smaller when the muscles of the iris are contracted. It requires muscular effort for the pupil to be in a contracted state. When the cat hiccups the purposefulness of that process of contracting the muscles of the iris is temporarily stopped as the hiccups distract the brain. Therefore the pupil enlarges and the eye becomes more dilated. That of course is a personal theory which I simply worked out because you cannot find the answer on the Internet. It makes for an interesting little video on a different level namely that you can see how the iris works and the pupil forms a slit. This slit pupil is very important to the domestic cat because it allows the animal to see in bright light and in extremely dark conditions as well. The slit aperture of the cat's pupil work sin harmony with the cat's eyelid which goes over the slit like a blind at the window of a person's home. The slight pupil also enhances a cat's depth perception.