|University of Bristol|
Maiasaura was a semi-quadrupedal dinosaur, probably foraging for most of its time on all fours, but maybe rearing up on its hindlimbs to escape predators. It had a solid ridge over its eyes and was 9 m in length.
The egg shell shape is not well preserved but appears overall rounded (Hirsch and Quinn,1990); 10-12 cm long and 7-9 cm wide, although slightly elongated with one end thicker than the other. The surface has ridges orientated longitudinally. This ornamentation could have strengthened the shell without unduly increasing the thickness of the shell, which would cause difficulty with respiration and hatching. The ornamentaion could have allowed the egg to buried under soil (maybe for protection or incubation). Gaps between the ridges would have allowed areas for respiration (Moratalla, 1994).