Dinosaur Egg - Paleobiology

Paleobiology

The shape of dinosaur eggs may reflect some aspects of their biology. In general, they are more symmetrical than bird eggs, implying that the head was not given more priority than other structures during development. Like birds, the shell was likely an important source of calcium, especially later in development. In modern reptiles, calcium from the shell is mobilized and stored in the yolk sac immediately prior to hatching. A spherical egg would have provided the smallest shell surface compared to the volume of the egg but many dinosaur eggs were elongated. This shape would have increased the total volume of an egg given the diameter of the passage between the pubic bones. It would also have greatly increased the area of calcium-rich shell available to the embryo and may have been important in animals producing precocious young with large well-developed legs and a long bony tail.

Dinosaur eggs vary in size, depending on the species. Among the largest are fossilized dinosaur eggs collected in the mid-1990s from Late Cretaceous rocks in China. These eggs are more than 60 cm (2 ft.) long and about 20 cm (8 in.) in diameter.