Dinosaurs: Male or Female?

One of the biggest mysteries in paleontology is whether or not an animal is female or male. It's been suggested that some dinosaurs, like Tyrannosaurus, had two forms. A bigger, more robust form, and a smaller, more gracile form. The smaller one represented the male and the larger one was female. That's how modern birds are. There are a few problems with this theory though. One, the dinosaurs other close relatives, the crocodilians, tend to be bigger when it's a male and smaller for the females. Second, this theory is far from full proof. It's very difficult to tell if an animal of any kind is male or female based only on their bones. Especially when that animal is extinct. Well, scientists recently found another way to figure out if a dinosaur is male or female. They did this experiment on Tyrannosaurus bones. When they studied the properties of the bones and soft tissue(they have recovered blood and tissue from dinosaur bones), they found that some had a large amount of a certain kind of calcium used to make eggs. This calcium is only found in female birds and reptiles that are ovulating(producing eggs). If a dinosaur has this calcium, they are female. While this method is probably more full proof, there are some bugs. The main thing is the dinosaur may be a female, but it's just not producing eggs. But it could be a male since they don't produce eggs at all. So we would never know. However, this study shows we are making big progress in our understanding of dinosaurs and prehistoric life in general. [img]http://media4.s-nbcnews.com/j/msnbc/Components/Photos/070606/070606_trex_hmed_9a.grid-6x2.jpg[/img] Tyrannosaurus, the dinosaur tested on the most.