Love me tender?
Competition for mates was a violent affair for prehistoric predators, say Alberta dinosaur experts.
British rock band Def Leppard likely didn’t have thunder lizards in mind when its members wrote the 1988 charttopper “Love Bites.”
But Tyrannosaurus rex probably did bite when it came to the mating game, as did other apex dinosaur predators, according to a new study by Alberta paleontologists on facial scarring found on fossilized tyrannosaurids.
The study, titled “Intraspecific facial bite marks in tyrannosaurids provide insight into sexual maturity and evolution of bird-like intersexual display,” was written by Caleb Brown and François Therrien, curators at the Royal Tyrrell Museum in Drumheller, Alberta, and Philip Currie, a paleontologist at the University of Alberta. It was published recently in the scientific journal Paleobiology.
Aggressive behaviour is common in the animal kingdom when it comes to competition for mates. However, paleontologists were unsure whether the same type of behaviour was displayed by dinosaurs — and, if so, by which ones?
For the study, the team examined 528 fossilized skull bones of albertosaurus, gorgosaurus, and daspletosaurus, cousins of the T. Rex that lived millions of years ago in western North America. The researchers recorded a total of 324 scars, mostly on the upper and lower jawbones, with many showing signs of advanced healing — a sign that the wounds were “repeated and non-lethal.” Around sixty per cent of the fossils showed signs of facial scarring. The team also found that facial scarring generally appeared around the onset of sexual maturity — when the fearsome carnivores had reached about half their adult size.
Other explanations for the scarring include disputes over territory or resources, fights to establish dominance, and overly frisky courtship rituals.
Interestingly, facial scarring is generally absent in small theropods such as dromaeosaurs (think the velociraptors of
Jurassic Park fame) and other groups closely related to birds. “It is possible that these smaller dinosaurs may have shifted their behaviour from physical aggression to attract mates to a more bird-like, visual-display-oriented selection, resulting from the evolution of complex feathers,” the museum said in a news release.