The invention of the cat flap is frequently attributed to Isaac Newton.

However, author Charles R. Gibson, writing about the life of Newton in 1921, recorded that "To this day students at Cambridge are told how there were two holes cut in the door of Newton's chamber: one hole, much larger than the other, for the use of his cat, the smaller one for the convenience of the kitten", but states that this goes in the face of "...a letter written by Newton's assistant [who] gives us the following information, which is direct evidence and not mere hearsay. `He kept neither dog nor cat in his chamber...'"