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Paleontologists working at the center India has made a rare discovery – a fossilized dinosaur hatchery with 92 nests and 256 eggs belonging to colonies of giant herbivorous titanosaurs.
An examination of the nests and their bowling ball-sized eggs has revealed intimate details about the lives of the colossal long-necked ones Sauropods that stalked what is now central India more than 66 million years ago.
The eggs, between 15 and 17 centimeters (6 in and 6.7 in) in diameter, likely belonged to a range of titanosaur species. The number of eggs in each nest ranged from one to 20, said the study’s lead author Guntupalli Prasad, a paleontologist in the Department of Geology at Delhi University. Many of the nests were found close together.
The results suggested that titanosaurs, which are among the largest dinosaurs that ever lived, weren’t always the most observant parents, Prasad said.
“Because titanosaurs were enormous in size, closely spaced nests would not have allowed them to visit the nests to maneuver and incubate the eggs or to feed the hatchlings…since the parents would step on the eggs and trample them.”
Finding a very large number of dinosaur nests is unusual because the conservation conditions would have to be “just about” for all the delicate eggs to be fossilized, said Dr. Darla Zelenitsky, associate professor of dinosaur paleobiology at the University of Calgary in Canada, examining dinosaur eggs. Zelenitsky was not involved in the research.
The first dinosaur eggs in the region were discovered in the 1990s, but the most recent study focused on a nest site in Dhar district in the state of Madhya Pradesh where excavations and fieldwork took place in 2017, 2018 and 2020.
The eggs discovered there were so well preserved that the team was able to detect degraded protein fragments from the eggshells.
Titanosaur nesting behavior shared characteristics with modern-day birds and crocodiles, research suggested.
From close proximity to the nests, the researchers concluded that the dinosaurs laid their eggs together in colonies, or colonies, as many birds do today.
“Such nesting colonies would have been a sight in the Cretaceous period, where the landscape would have been dotted with large numbers of large dinosaur nests,” Zelenitsky said.
Prasad said one particular egg — known as an ovum-in-ovo or egg-in-egg — that the team studied displayed bird-like reproductive behavior, suggesting that, much like birds, some dinosaurs may have laid eggs one at a time. ovum-in-ovo Molds occur in birds when an egg is embedded in another egg that is still in the process of formation before they are laid.
“Sequential laying is the release of eggs one after the other with a certain time gap between two laying events. This is observed in birds. In contrast, modern reptiles, such as turtles and crocodiles, lay all their eggs together as a clutch,” he said.
The eggs would have been laid in swampy flat land and buried in shallow pits, similar to the nesting sites of modern crocodiles, Prasad said. Similar to crocodile hatcheries, nesting near water may have been important to prevent the eggs from drying out and the offspring dying before hatching, Zelenitsky added.
But unlike birds and crocodiles, both of which hatch their eggs, Prasad said that due to the physical properties of the nests, titanosaurs likely laid their eggs and then left the baby dinos to fend for themselves — although more data is needed to be sure.
Other dinosaurs were considered more attentive parents. For example, in Mongolia in the 1920s, a dinosaur was discovered lying near a nest of eggs thought to have belonged to a rival. Paleontologists at the time assumed the animal had died trying to plunder the nest – and dubbed the creature Oviraptor, or “egg thief”.
The reputation of the so-called dinosaur thief was not restored until the 1990s, when another discovery revealed that the eggs indeed his own, and that the creature was probably perched on top of them in a neatly arranged nest.