Baiji, like other dolphins, have streamlined, fusiform bodies. They have rounded flippers and long, beaklike, upturned snouts, which are completely hairless. Their small but functional eyes sit high on their heads, and their blowholes are elliptical and oriented longitudinally. Baiji are pale blue-grey dorsally and white ventrally. They have 30-36 teeth per side of both the upper and lower jaws. Baiji have no fore-stomachs but their main stomachs consist of three chambers, and they lack ceca. The skulls of these dolphins lack maxillary crests, and the palatal portions of the maxillae contact one another.

Female baiji are larger than males. Females range from 185 to 253 cm in length and weigh 64-167 kg, while males range from 141 to 216 cm in length and weigh 42-125 kg.

Range mass: 42 to 167 kg.

Range length: 141 to 253 cm.

Sexual Dimorphism: female larger