Tanklike armored dinosaurs probably interacted with each other – not just predators – with huge, bony spikes attached to the ends of their tails. Through new fossil discoveries, researchers are getting a clearer understanding of how these tough plant eaters can use their evil weapons.
Many dinosaurs known as ankylosaurids sported a heavy, potentially dinosaur-sized tail club. This natural sledgehammer has long been considered by both scientists and artists as a defensive weapon against predators, says Victoria Arbour, a paleontologist at the Regional Museum of British Columbia in Victoria, Canada.
Fossil evidence of tail club shields was largely lacking until Arbor and his colleagues used multiple rock cuts from the same skeleton to describe a new armored dinosaur; Zuul the leg-destroyerin 2017 (SN: 6/12/17)).
The dinosaur had five broken nails in its sides. The team’s statistical analysis showed that damaged spikes clustered in specific regions of the body. If a large carnivorous dinosaur did these injuries, says Arbour, it would be random and would include bite and scratch marks.
But injuries with clubs are more consistent, researchers report on Dec. 7 Biology Letters.
The armored tails of dinosaurs are either absent or too small to mount for greater defense, and are proportional to their age. Similar growth patterns occur in some modern animal weapons such as horns. It is possible that dinosaurs like dinosaurs dispersed among themselves for mates, food or territory much like the deer and the cheetah do today.
That and the tail may also be used in a pinch. “Having a tail club at the ankles of a bipedal raptor can be an effective weapon,” says Arbour.
“Ankylosaurs are often portrayed as stupid, loner dinosaurs,” he adds. The findings “show” that they probably had much more complex behaviors than we give them credit for.
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