Combat And Cannibalism In An Ancient Predatory Dinosaur?
A new paper published this month in PeerJ has revealed the surprisingly dangerous world of dinosaur adolescence. Fossil remains from a smaller relative of the more familiar Tyrannosaurus rex shows extensive damage suggesting that combat and even cannibalism was common amongst these large predators.
Daspletosaurus was a genus of predatory theropod dinosaur which once lived in western North America. Although somewhat more ancient and smaller then Tyrannosaurus it was still an impressive beast with adults reaching around 8-9 metres in length, and like their younger cousins they were predators and scavengers. A juvenile specimen from Alberta, Canada has revealed some surprising details of behaviour in these ancient animals. The skull belonged to a small specimen, not yet fully grown, which was around 6m long and based on an analysis of the bones it was probably a sub-adult, an age roughly approximate to the late teens in humans. The skull showed numerous wounds many of which were similar in shape to Daspletosaurus teeth and although much of the damage could not be definitively attributed to bites and there was one wound in particular which may well have been. At the back of the skull is a circular puncture around which some of the bone has broken off, and which almost perfectly matches the shape of a Daspletosaurus tooth. This strongly suggests that combat was common and many of the other injuries may well have been caused by such fights. Interestingly all these wounds showed evidence of healing. This means that although much of the damage is severe none of it was life threatening and in fact this juvenile theropod had apparently recovered from many such injuries.
What happened after this animal died however, is equally fascinating. Although there is no obvious wound which seems to have killed it and consequently it is impossible to say how this animal died, there is some damage to the fossil’s jaw though which suggests that the body was at least partially eaten after death. Whether or not this predation was from a fellow Daspletosaurus is difficult to say with certainty but cannibalism has been documented in other, related, species and given the clear evidence of conflict during the animal’s life it is certainly possible.
References: Hone, D.W.E., & Tanke, D.H., 2015. Pre- and postmorten tyrannosaurid bite marks on the remains of Daspletosaurus (Tyrannosaurinae: Theropod) from Dinosaur Provincial Park, Alberta, Canada. PeerJ. DOI: 10.7717/peerj.885
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