Blowing bubbles helps vertical sperm whales sleep soundly The TimesSecrets of how sperm whales sleep revealed The TelegraphResearchers tag 42 sleeping giants in Arctic Circle – and make breathtaking discovery BBC Wildlife MagazineSperm Whales “Regularly” Toot Gas To Hang Motionless In The Ocean While They Sleep IFLScienceSperm Whale rest vertically (IMAGE) EurekAlert!
