Tions and hip structure has borne out this comparison. In terms of limb length, shape of the hip bones, and position of the hip socket, "Hesperornis" is particularly similar to the common loon ("Gavia immer"), probably exhibiting a very similar manner of locomotion on land and in water. Like loons, "Hesperornis" were probably excellent foot-propelled divers, but might have been ungainly on land. Like loons, the legs were probably encased inside the body wall up to the ankle, causing the feet to jut out to the sides near the tail. This would have prevented them from bringing the legs underneath the body to stand, or under the center of gravity to walk. Instead, they likely moved on land by pushing themselves along on their bellies, like modern seals. However, more recent studies on hesperornithean hindlimbs suggest they were more functionally similar to those of the still upright walking cormorants.