Dinosaurs were hatched as new offspring from eggs laid by female dinosaurs. Their eggs were identified and described for the first time in 1859. These eggs were elongated or round and had brittle shells. Other than oval and elongated some potato-shaped, football-shaped, grapefruit-sized eggs have also been observed. There have been different egg placements such as in the groups of 5-25, in the circle-shaped, and spiral-shaped arrangement. While some dinosaurs also laid eggs in rows.
The internal composition of these eggs was found to be like the primitive mammals, reptiles, and birds. Their eggs were provided with a membrane (amnion) to keep the embryo moist, and well-shaped. Some dinosaurs were much careful about their eggs, while some were not.
As dinosaurs were bigger, so there are many unanswered questions that how their females were laying eggs without breaking. In the standing conditions, the eggs are supposed to break as they might be dropped from a minimum height of about 8-12 feet. Some scientists are hypothesizing that female dinosaurs had tubes for the safe laying of eggs.
Many dinosaur eggs have been found at various sites in China, the USA, France, Spain, Mongolia, India, and Argentina. Rarely, some preserved parts of embryos have also been found and are being used in the scientific studies to know about the development of dinosaurs.
Scientific Evidence of Dinosaur Eggs
Scientists have found various eggs and nests of dinosaurs which are approximately 80 million years old. These findings are providing clear evidence that dinosaurs had complex nesting behaviors and reproductive systems that dates to 66 million years ago.
Findings of various scientific studies conducted by paleontologists have reported that dinosaur eggs were soft, and they buried their eggs in the deeper soil layers. Burying was greatly helpful to protect the eggs from crumbling and drying. Moreover, temperature around the eggs is lower, which was greatly helpful to ensure slow development, and advanced hatchling. This in turn leads to less parental care and protection of eggs.
Nesting of Dinosaurs
Most paleontologists are of the opinion that colonial nesting behavior was first observed in the dinosaurs. Their nesting behavior was quite variable from simple pits in the sand or earth to complicated nests in the mud rims. Some dinosaurs lived in larger groups, and some of them lived all alone. Some dinosaur nests have also been observed in the form of holes scooping out of the ground.
Their nests are observed at 25-30 feet apart from each other. Scientists think that they managed this distance for the adjustment of at least 1 adult in that space. A group consisting of 40 nests has been discovered in Montana covering 1 hectare of land. Although nesting behavior is different in different dinosaurs, fossil evidence from scientific studies has indicated a high level of social behavior, nesting behavior, and parental care.