In 1799, a British scientist took scissors to a strange pelt arriving from Australia, certain he was the victim of a hoax. A duck's bill grafted onto a beaver's body simply could not be real. He never found the stitches.

This deep dive unpacks why the platypus, far from a biological mistake, is an evolutionary masterpiece. Pulling from historical accounts, genetic sequencing, and behavioral studies, we explore the bizarre adaptations that make this egg-laying mammal one of the most highly specialized survivors on Earth, and why it is now under threat.

• How it feeds its young, called puggles, by oozing milk through modified sweat glands since it has no teats
• Why it has no stomach, having lost the genes for acidic digestive enzymes entirely
• The 40,000 electroreceptors in its bill that let it hunt blind, deaf, and without smell by sensing prey's electrical fields
• Its astonishing 10 sex chromosomes, with one bearing a striking resemblance to the bird Z chromosome
• Why platypus habitat has shrunk 22 percent in 30 years, with models predicting up to a 73 percent population drop by 2070