Did Isaac Newton Really Invent the Cat Door?

The claim that Isaac Newton invented the cat door is more of a popular anecdote than a verified historical fact. According to the story, Newton invented a small door for his cat named Spithead so that it could come and go freely without interrupting his work, particularly during his time studying at the University of Cambridge.

While it is a charming story that reflects Newton's practical ingenuity, there is no concrete evidence or documentation to confirm that he specifically created the first cat door. The story serves more as a testament to Newton's character and his relationship with his pet than as a definitive historical account.

The True Inventor: Bartholomew Cat

No, the 'Cat door' was invented by a tragically dyslexic Yorkshireman named Bartholomew Cat, who designed it to allow his pet dog, a whippet, to enter the garden without pestering him. Yorkshire is famous for men with whippets and cat flaps.

Historical Context and Early Cat Doors

Even though the story about Newton invented the cat door has been around for a while, it is almost certainly false. Unlike dogs which were domesticated from wolves by selective breeding, scientists believe that cats "domesticated themselves." This occurred when human agriculture and settlement attracted rats and mice, which became pests for humans and also attracted cats.

The way cats took advantage of this and became comfortable around humans led to the modern pet cats we have today. These cats are still more independent than dogs. Small holes in doors and rooftops have always been one of the main ways humans allowed cats into their homes, barns, and other buildings to help control the populations of rats and mice. To this day, you can find such small apertures in very old buildings throughout southern Europe. They are known in Spanish as gateras, in French as chatières, and in Italian as gattaiole.

Artistic References to Cat Doors

There’s also a probable reference to such a hole in Chaucer's "Miller's Tale" from Canterbury Tales of the late 14th century:

"An hole he foond ful lowe upon a bordn
Ther as the cat was wont in for to crepen
And at the hole he looked in ful depen
And at the last he hadde of hym a sighte."

The association between cat doors and Newton seems to derive from a memoir published in 1827 by a man called John Martin Frederick Wright titled Alma Mater: Or Seven Years at the University of Cambridge. Wright doesn’t say that Newton invented the cat door but rather that he kept a female cat and, after the cat had a kitten, "issued orders to the college carpenter to make two holes in the door—one for the cat and the other for the kitten."

?Evidently, this story was intended not to underline Newton's practical genius but the opposite: to suggest that despite his eminence as a mathematical scientist, he lacked the common sense to realize that the kitten could follow its mother through a single opening. This is part of an English tradition of making fun of Newton's supposed absentmindedness.

Additional Insights into Newton’s Inventions

Newton was actually a great practical inventor. As a child, he was fascinated by the devices and demonstrations described in John Bate's The Mysteryes of Nature and Art and reportedly built a working model of the windmill that was being raised in the vicinity, recruiting a mouse to turn a wheel that moved his model windmill. The adult Newton made the first practical reflecting telescope, preparing the metal alloy for the mirror and polishing it to the requisite curvature himself. He also prepared the first prototype of a sextant.

Newton biographer Richard S. Westfall noted that we don’t even have contemporary records indicating that Newton kept pets at all.