The paternal care, common among birds, may have its origins among dinosaurs. It appears that many dinosaur fathers spent a lot of time around the nest watching the kids.

Scientists who examined the fossilized remains of three types of medium-sized dinosaurs, Troodon, Oviraptor and Citipati that lived 75 million years ago found with large clutches of eggs, have concluded that the males and not the females seem to have guarded the nests and brooded the eggs.

 

These kinds of dinosaur eggs were asymmetrical rather than round and the shells were multilayered, like those of birds. The three types of dinosaurs also produced unusually large clutches of eggs, with as many as 30 in a nest. The scientists think that at least in these types of dinosaurs, the males may have mated with several females that laid eggs in one large clutch. When the females left, the males incubated and protected the eggs on their own. Fossils from adult Troodon, Oviraptor and Citipati dinosaurs were found in a brooding position, indicating that they died in the act of caring for the brood.  

   

Florida State University paleo-biologist Greg Erickson said there was no evidence of medullary bone - the extra bone tissue inside long bones that breeding female birds and dinosaurs use for making eggs by storing minerals - or evidence of another process by which female reptiles such as crocodiles acquire mineral salts to make eggs. Thereafter, the absence of this female-specific bone marker indicates that the dinosaurs found near the nests were males.

 

The dinosaur body-to-clutch ratios most closely matched that of a group of primitive birds - ostriches, rheas and emus - that all have a "paternal model" of care of the eggs and young.

 

Males protect or support offspring in more than 90 percent of bird species - a quite rare attribute for animal behaviour. In mammals, males provide parental care in 5 percent of species, and it's even rarer in reptiles.