Bonobos (also called pygmy chimpanzees) can walk upright just like humans do.
Cow Sleep
Cow Sleep Cows sleep standing up but only dream while lying
down. The ancestors of cows had to be on the look out for
predators, so they evolved to take short naps standing up,
sensitive to any danger approaching them. Dream sleep is much
deeper, but if you dream standing up you will fall over because
your muscles relax. Cows get around this by having their deep sleep
lying down while surrounded by other cattle. JULY 14, 2000
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