Paleontology is part science and part guesswork. At least that is the opinion of most other disciplines in science. The reality is that paleontologists are studying artifacts from so long ago that they are dealing with the minimum level of data. For them to make any analysis a few leaps in judgment must be made. Yet as science continues to improve many of the findings are being disproved. For example, when you watch Jurassic park you see all the dinosaurs with scales like a crocodile yet it is now believed that many may have been covered in hair, how could we know by just looking at bones? For years paleontologists have made grand assumptions about sex too, these are now coming under doubt.
The truth is that it is incredibly hard to tell anything by just looking at bones. While with some species of animals it is easy, for most they don’t tell you much at all. Often if they have died by a brutal body blow you can tell by the damage to the bones. Or if they had a growth defect you can see how the bones have altered from the norm. Dinosaur bones are incredibly useful in understanding the size and stature of each type of dinosaur. They can tell you how large the skull was which may indicate something about the size of the brain. They can tell you how large the legs were which can tell you something about whether they were prey or predator, fast or slow. They can tell you how long the neck was which can indicate whether they grazed from treetops of fed from the ground. But after that, and that is a lot, they become little more than skeletons.
For years paleontologists made broad claims about the sex of dinosaurs (not their sex life). For example, after finding some dinosaur bones of a number of T Rex, paleontologists claimed that female T Rex was larger than males. However, on the limited amount of bones, they found this claim was pure speculation.
A new study has cast further doubt about these paleontologist claims. The study came out of the Queen Mary University of London. The researchers there looked at the skulls of gharials. These are a modern-day crocodile and are the closest thing that we have to dinosaurs still in existence. They tried to look at the skulls alone to determine if it was really possible to tell the difference between male and female. The majority of male gharials are larger than females, so a larger skull does indicate a male however when looking at the true picture they realized this is often incorrect as on some occasions the female skull is larger. Male gharials do have a fleshy growth at the end of their nose called a ghara, females do not. However, this is where the plot thickens.
The ghara would not survive as a fossil so by looking at the skulls alone it is difficult to tell whether one is male or female. The ghara is supported by a hollow in the skull so it is possible to distinguish between the two by the skull alone but far from easy. The team of researchers looked at over 100 examples of gharials and found that without the narial fossa it was impossible to tell the sexes apart. Basically, the skull size told them nothing.
When animals have sexual dimorphism (differences in attributes based on sex) it is possible to tell them apart but it is impossible to know whether dinosaurs have this by looking at the skeleton alone. This shows that paleontologists and scientists, in general, must be careful not to make too many leaps based on assumptions.