All that you wanted to know about wombat butts

https://www.theguardian.com/science/2020/nov/04/wombats-deadly-bums-how-they-use-their-skull-crushing-rumps-to-fight-play-and-flirt?utm_term=de7ab8186e4aabda7796bf292d4dc8a5&utm_campaign=GuardianTodayUS&utm_source=esp&utm_medium=Email&CMP=GTUS_email 

(Thanks for the link, Ed!)