Prehistoric Animals Swung Tails Like Baseball Bats

Aug. 25, 2009 -- Enormous prehistoric armored mammals called glyptodonts swung their spiked tails just as athletes swing tennis rackets and baseball bats, according to a new study.

These massive animals even had a "sweet spot" on their tails right where the biggest, sharpest spike was situated.

The findings about glyptodonts -- which looked like a cross between an armadillo and a Volkswagen beetle car -- apply to dinosaurs that also had spiked tails, the team of researchers believes.

Both glyptodonts and dinosaurs possessed the lethal tail "sweet spot," technically known as the center of percussion.

"The center of percussion is a point where you can deliver a very powerful blow with a baseball bat, a tennis racket, a sword, an axe or any hand-held implement, but the forces against your hands are almost zero," said lead author Rudemar Ernesto Blanco, a researcher in the Institute of Physics at the Faculty of Sciences in Montevideo, Uruguay.

Glyptodonts lived in both South and North America, first emerging around 2.5 million years ago and going extinct 8,000 years ago, possibly due to hunting by humans.

WATCH VIDEO: Horns, spikes and plates got a lot of attention in the days of dinos.

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Blanco and colleagues Washington Jones and Andres Rinderknecht studied tail remains for the giant armored mammals at three museums, including the Argentinean Museum of Natural Sciences.

They determined that in many glyptodont species, such as Doedicurus clavicaudatus, rings of bony scutes, or plates, on the tails were fused, turning the animal's tail into something akin to a baseball bat.

Measurements and calculations found that each tail's sweet spot landed right where scientists had previously speculated the biggest spikes once existed: at the center end of the tail.

Like the horns of living rhinos, these spikes did not preserve well once the animal died.

The study, published in the latest Proceedings of the Royal Society B, "reinforces the idea that in that (sweet spot) was something useful to cause more damage during an impact," Blanco said, adding that glyptodonts might have evolved this defensive technique to help fight off "terror birds," prehistoric South America's dominant predator.