Recent research work done by scientists shows a surprising fact about dinosaurs: the males were taking care of the nests and brooded the eggs laid by several other females.

The study involved the discovery of fossilized remains of three types of medium-sized dinosaurs who were found with large clutches of eggs. The study, which was published on Thursday in the journal Science, explains that this kind of behavior is mostly seen in certain species of birds which still exist. This fact goes along just fine with the theory of most scientist according to which birds evolved from small predatory dinosaurs.

The three types of dinosaurs which were the subject of the aforementioned study are Troodon, Oviraptor and Citipati. They lived about 75 million years ago and were theropods. This group of dinosaurs also includes the famous Tyrannosaurus rex and Giganotosaurus.

The findings of this study "sheds light on the origins of parental care systems in birds," said Frankie D. Jackson, a paleontologist at Montana State University, and one of the authors of the study.

It is a distinct and rare attribute in the animal world for males to protect offspring. However, it can be seen in more than 90 percent of bird species. In mammals, in only 5 percent of the species the males provide protection and care to their offspring while in reptiles, this is even rarer.

"There are a lot of characteristics that we once thought were unique to birds that are turning out not to be -- that they first arose in their theropod ancestors," Mr. Jackson added according to Reuters.