How do scientists study the behaviour of dinosaurs, who died 65 million years ago? After all, dinosaur fossils are rare enough as it is, and most are fragments and difficult to work with.
Author
- David Hone
Senior Lecturer in Zoology, Queen Mary University of London
This is something that palaeontologists have been working on since the earliest days of research on these incredible animals. Until recently, this was often only in vague terms of, for example, which animals were herbivores or carnivores .
But new opportunities are becoming available to us. Palaeontologists have recently pieced together the colours and patterns of some feathered dinosaurs , using electron microscopes to see tiny preserved structures that used to contain the pigments of the animals in life. This is something that scientists used to think was probably impossible.
But right now it can only tell us so much - it just tells us the colour of the individual animal at the time of its death.
Studying more specimens of the same species could reveal if males and females were the same colours or if they differed, and if these feathers underwent seasonal changes or varied with the environment. Perhaps they turned white in winter as camouflage. Maybe feathers were different colours in different regions. This would suggest that the local environment helped these dinosaurs to hide and that they cannot have been wide ranging or their camouflage would not work.
Perhaps the males were brightly coloured to attract mates, or perhaps both were, which would suggest both sexes were involved in rearing their offspring.
This is something scientists should be able to tackle in the coming years. For some species at least, such as the small feathered dinosaur Anchiornis, we have the fossils, and we have the techniques. We just need to extract the data from the dinosaur fossils we have.
We already have a good idea of what colours and patterns mean for different groups of living animals, so we can apply some of this knowledge to dinosaurs. However, much of researchers' work on dinosaur behaviour has been stunted by a poor use of the behaviour of modern animals as a template for dinosaurs, and a tendency to focus on special specimens as being representative of bigger patterns.
For example, we have well-studied fossils of carnivorous dinosaurs with the bones of other animals inside them. Although is incontrovertible that the carnivorous dinosaurs ate these other animals, it is hard - or even impossible - to know if the prey was scavenged or if it was hunted by the dinosaur.
It's too easy to think the dinosaur lived on the species the bones belonged to. Bones tend to survive the fossilisation process, but the animal might have mostly eaten muscle and organs, or even insects and they wouldn't show up . Although such finds are important, we need to take them as evidence that something happened once, not that it was a habitual activity. Then we can go in search of other evidence to test or reject such an idea.
In that context, we really are blessed. New fossils and new techniques (such as CT scans to get inside skulls to dinosaur brain to assess them) are still being discovered. And there are perhaps more dinosaur researchers than ever before , even if that total is not that high compared to other disciplines.
It means that we are continually getting insights and new lines of evidence about things like how and what dinosaurs ate, their underlying physiology, the environments in which they lived, how they moved, and how they changed as they grew. This is the raw material of studies for behaviour, and adding this kind of data to our understanding of the behaviour of modern animals has enormous potential for future studies of dinosaurs (and other prehistoric animals).
Another angle to consider is how palaeontologists formulate their ideas about dinosaur behaviour in the first place. For example, although we have numerous examples of several individuals of a dinosaur species found together , this doesn't meant that the species habitually lived in groups, let alone that their near relatives did.
Cats are generally solitary animals , but if you inferred the social behaviour of lions or cheetah from tigers and puma , you'd think these animals lived their lives alone. The fact is that lions and male cheetah usually live in groups.
But they are sometimes solitary and will switch between being solo or living together at various times in their lives. So taking from the position that one group of dinosaurs died near each other means they and their relatives lived together won't help us understand how they were really living.
The future of the study of dinosaur behaviour is looking bright. This is why I wanted to write a book on the subject and to explore the issues we have had before, but frame the successes that are happening. Coupled with more rigorous attempts to investigate and test our hypotheses, we can establish a much firmer ground for understanding how these incredible creatures lived.
David Hone does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.
