New Study Refutes Previous Research on Dinosaur Incubation Habits

New research on the incubation behaviors of birds refutes a prior study that reported bird behavior could be used to determine that some male dinosaurs were tasked with incubating eggs.

The new study, carried out by researchers at University of Lincoln and George Mason University, aimed to test a hypothesis of whether birds today could be used to determine the incubation behaviors of ancestors of birds, a carnivorous group of dinosaurs known as theropods.

The researchers determined that when dinosaurs roamed the earth, the parental task of incubating the eggs was likely shared by both males and females. The conclusion contradicts a previous theory that only male theropods incubated eggs.

Charles Deeming, a co-author of the study, disagreed with a 2009 study published in the journal Science suggested that it was males of the small carnivorous dinosaurs Troodon and Oviraptor that incubated their eggs.

"Irrespective of whether you accept the idea of Theropod dinosaurs sitting on eggs like birds or not, the analysis raised some concerns that we wanted to address. We decided to repeat the study with a larger data set and a better understanding of bird biology because other paleontologists were starting to use the original results in Science in order to predict the incubation behavior of other dinosaur species," Deeming said in a statement.

"Our analysis of the relationship between female body mass and clutch mass was interesting in its own right but also showed that it was not possible to conclude anything about incubation in extinct distant relatives of the birds."

Geoff Birchard from George Mason University said the prior study was incorrect in its prediction of ancient parental behaviors.

"The previous study was carried out to infer the type of parental care in dinosaurs that are closely related to birds. That study proposed that paternal care was present in these dinosaurs and this form of care was the ancestral condition for birds. Our new analysis, based on three times as many species as in the previous study, indicates that parental care cannot be inferred from simple analyses of the relationship of body size to shape, anatomy, physiology and behavior. Such analyses ought to take into account factors such as shared evolutionary history and maturity at hatching. However, our data does suggest that the dinosaurs used in the previous study were likely to be quite mature at birth."

The new study is published in the journal Biology Letters.