Horses can sleep standing up but can’t get REM sleep without lying down.
This is also true for cows, giraffes, camels, and zebras. They can sleep while standing up, but in order to get REM sleep, they have to lie down for a while.
Einstein didn’t wear socks
“When I was young I found out that the big toe always ends up making a hole in a sock. So I stopped wearing socks.” “Why wear both shoes and socks when one of them would do nicely.”