鸭嘴兽和针鼹都是卵生哺乳动物,都没有乳头,每个乳孔的位置在一根长毛的底部,乳汁顺着特别粗糙的“奶毛”流到外面。鸭嘴兽哺乳时,雌兽仰卧,幼仔趴在母体腹部上面,用舌头舔食乳汁。针鼹把卵产在育儿袋里,袋内有乳腺的开口让幼仔舔食。 Platypuses and echidnas are all oviparous mammals with no nipples. Each breast hole is located on the bottom of a long hair, with milk flowing out along a particularly rough “milk wool.” Platypus breastfeeding, the female beast supine, lying above the mother’s abdomen, licking milk with his tongue. Echidna eggs in the childcare bag, the bag has a breast opening let pups lick.