여러명 모여서 10-15분 정도 같이 잔답니다.

When  whales need a nap, they take a deep breath, dive about 15 meters and  place themselves in perfectly level vertical patterns. They sleep  peacefully between 10 and 15 minutes, in groups of 5 or 6 whales,  presumably for protection. No one knew that whales slept vertically  until a 2008 study documented the behavior. And nobody captured really  good photographs in nature until 2017. French photographr Stephane  Granzotto was documenting whales in the Mediterranean for his book on  creatures when he came across these sleeping whales.