New Scientist
Image: Georg Schwalbach (GS1311)
Male dinosaurs may not have had a caring side after all. Five years ago a study of theropod dinosaurs concluded that it was male dinosaurs that incubated the eggs. Now a new analysis of the same data is challenging that finding.
It is notoriously difficult to work out how long-extinct animals behaved, but a few fossils found in recent decades show clearly that some Mesozoic theropods, a bipedal group of carnivorous dinosaurs, made – and sat on – nests, apparently in the same way that birds do today.
In 2008, David Varricchio at Montana State University in Bozeman and his colleagues set about learning more about dinosaur parenting. Their strategy was to combine data from those fossils with what we know about how their descendants behave today.
They deduced the adult body mass of the fossilised nesting dinosaurs, and counted the maximum number of fossil eggs in the nests attributed to each species. They then compared their figures to similar data from studies of birds and crocodiles.
This revealed that nesting therapod dinosaurs produced unusually large clutches for their body mass – a pattern often seen in birds in which the male alone cares for the eggs. In these species, female birds can afford to plough more resources into bigger clutches, because after laying the female is free to leave the nest and replenish her energy reserves. Varrichio’s team concluded that among therapods, the males were also the egg incubators.
Not so fast, says Charles Deeming at the University of Lincoln, UK. His team has now reanalysed the data and come to a different conclusion. Read more on newscientist.com…
