When I was young, I used to believe that the number of nipples (which I called "nursers") on our cats & dogs would tell you how many kittens/puppies would be in the litter. So when one of our cats was pregnant and I counted six or eight or whatever nursers, I told my dad she was going to have that many babies. He was more than amused....he still mentions it to this day.
I also thought that cats had engines inside that caused them to purr.
A childhood belief about cats and dogs

others believed things like this
- My sister and I thought cats and dogs were the same animal, the dogs were male and the cats were female.— Paul
- I used to believe all dogs were male and all cats were female. I still call dogs "boy" and cats "girl." — Kelly F.
- I use to believe that cats and dogs were the same species; cats were girls and dogs were boys.— poopcrystals
- When I was a little girl I used to believe cats were broken because of their moter sound when they purr— Shaune F.
- I alwaysused to think white cats were girls, and black cats were male ...— Smiley Face
- I used to believe that the cats eyes in the road...reflectors...were the eyeballs from real cats.— Liza P.