Bird-like Dinosaurs 'Troodons' Laid Eggs in Shared Nest 74 Million Years Ago, Study Says

Researchers have discovered that bird-like dinosaurs, known as troodons, had sufficiently high body temperatures to lay eggs. What's more is that they did not hog their own nests. Instead, they had shared nests where several other nestmates laid over 20 eggs. These bird-like dinosaurs also brooded the eggs to maintain their warmth.

Unlike Other Dinosaurs, Troodons Lay Eggs in a Nest

According to Live Science, the majority of dinosaurs are known to lay their eggs and bury them under the ground. This is how they end up incubating their eggs.

This, however, is not the case for Troodons, which were small predatory dinosaurs from around 74 million years ago and are closely associated with present-day birds.

In fact, according to Lethbridge News Now, François Therrien, one of the study's co-authors and a paleontologist from the Royal Tyrrell Museum, said that these meter-long carnivorous dinosaurs are thought to have contributed to the rise of birds.

Troodons Could Self-Regulate Their Body Temperatures

Eggshell fossils have shown that Troodons were actually endotherms, which means that they were warm-blooded and that they had the ability to self-regulate their own temperatures. Hence, these creatures had the capacity to maintain sufficiently high temperatures for egg brooding. This high body temperature of the creatures is similar to that of birds.

The study was published in the PNAS journal. Darla Zelenitsky, a co-author of the study and a paleontologist from the University of Calgary, notes that these creatures may even switch to and from a warm-blooded state and a cold-blooded torpor state. This is known as heterothermy, which is a common strategy for present-day birds.

In the study, the researchers looked into eggshell mineralization patterns from eggs of the Troodon formosus species. They compared it to that of modern reptiles and birds.

They also employed a specific technique that looked into the eggshell's calcite content and pinpointed the temperature and speed of its formation.

To their surprise, the researchers found out that the T. formosus had eggshell mineralization that was reptile-like and slow, even if it had evolved traits that are similar to those of birds. Mattia Tagliavento, the study's lead author and a postdoctoral paleontology researcher from Goethe University, notes that through their work, they may demonstrate how the troodon was in-between both birds and reptiles, as it may have produced two eggs at once and laid them. Such a pace is slower compared to present-day birds.

Troodons Could Have Shared Nests

They also made use of the creature's weight and eggshell calcite content estimates to see that a female troodon could have laid four to six eggs in a single clutch. This did not align with the typical egg number spotted in nests.

Zelenitsky notes that one dinosaur could not have laid more than 20 eggs in a reasonable period in order to make sure that the egg and embryo survived.

Such findings suggest that female troodons had nestmates. They laid eggs and tended them alongside other females.

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