We often receive reports of sloths that have been severely burnt or attacked with machetes as they are spotted with what appears to be a horrifying injury on the upper back. What looks like an open wound or blood-stained fur, however, is in fact completely normal. All male three-fingered sloths develop this striking and totally unexpected feature called a ‘speculum’ at sexual maturity. Credit @nature_by_pil | The Sloth Conservation Foundation