In Depth
For lack of a better description, Castorocauda was basically like an otter or beaver that lived during the Jurassic. However, while Castorocauda superficially looks like them, the genus is in no way a direct relation to them, Instead, Castorocauda is what is known as a docodont mammaliform, and a member of a group that has no surviving descendents today. Nevertheless, the genus and type species name of Castorocauda lutrasimilis does translate as ‘beaver tail similar to otter’.
The adaptations made by Castorocauda to a semi-aquatic lifestyle are interpreted as being a case of convergent evolution, the process where two unrelated animals evolve the same adaptations to deal with the same survival situation. Castorocauda would have spent time hunting within the water, perhaps looking for fish and/or crustaceans while returning to land to rest and raise young. While on land Castorocauda would have been more vulnerable to predators especially smaller theropod dinosaurs. Modern otters usually shelter in burrows however, and this raises the question, if Castorocauda developed similar a body form to otters, then did Castorocauda also develop similar behaviour too?
Further Reading
- A swimming mammaliaform from the middle Jurassic and ecomorphological diversification of early mammals. - Science 311:1123-1127. - Q. Ji, Z.-X. Luo, C.-X. Yuan & A. R. Tabrum - 2006.
