Do platypuses really sweat milk?
They secrete milk from specialised mammary glands, just like humans and other mammals. But platypuses don’t have teats, so the milk just oozes from the surface of their skin. This makes it look like sweat, but in fact platypuses are aquatic and don’t produce regular sweat at all. Since this delivery system is less hygienic than the direct nipple-inmouth method, platypus milk contains powerful antibacterial proteins to protect the babies from illness. These proteins may be a useful source of future antibiotics.