Why is it that many dinosaurs had formidable tail weapons – such as the ankylosaurus, with its clubbed tail, and the stegosaurus, with its spear-like spikes – but animals today do not?
Victoria Arbour, a paleontologist at the University of Toronto and the ROM, decided to figure out why. With Lindsay Zanno, a paleontologist from North Carolina State University, the researcher compiled data about nearly 300 mammals, reptiles, birds and dinosaurs, both extinct and living, looking for commonalities, according to a report in the New York Times.
The Times reports that the team identified three characteristics in land-dwelling mammals, reptiles and nonavian dinosaurs that may be linked with evolving bony tail weapons: being large (the size of a mountain goat or bigger), eating plants and already having an armoured body.
“That’s a really rare combination no matter what time period you’re looking at,” Arbour told the Times.
Many modern animals that use tails as weapons – like porcupines – have tails made of keratin, not bone. Modern lizards like iguanas, which can lash their tails, do not have spikes.