Tail blow energy and carapace fractures in a large glyptodont (Mammalia, Xenarthra)

Glyptodonts had muscular tails terminating, in many cases, with a rigid bony sheath which, in Doedicurus and Panochthus, was a formidable club. Some carapaces show fractures which have been interpreted as resulting from intraspecific fights. We estimate the energy that the tail muscles could have supplied for a blow and the energy required to fracture the carapace, and obtain results of the same order of magnitude. Thus it is not unreasonable to interpret the observed damage as resulting from fights. A space between the thoracic and lumbar vertebral column and the carapace may have been occupied by a fatty pad which would have served as a protective cushion, reducing the force of impacts. (C) 1999 The Linnean Society of London.