Platypuses lack a true stomach; their esophagus connects directly to the intestines. They swallow food whole, grinding it with keratinized pads. Stomach-less digestion allows rapid processing of high-protein diets. It may also reduce energy costs of maintaining an acidic stomach. This system is unusual among vertebrates but effective for a diet of small aquatic animals. The intestines produce digestive enzymes to break down prey efficiently. This adaptation suits constant, small-meal feeding.
Unique digestive anatomy highlights evolutionary diversity.
It shows mammals can thrive without standard digestive structures.
Platypuses’ diet is efficiently processed despite lacking a stomach.
Smithsonian National Zoo (si.edu)