Sabertooth

1. What Is a Sabertooth?

3 1 What Is a Sabertooth? Today sabertooths are a familiar kind of extinct creatures for scientists and for many laypersons, but in the early days of paleontology , not even scientists knew that such a thing as a sabertoothed predator had ever existed. Consequently, when early paleontologists first tried to make sense of fragmentary fossils of sabertooths, they attributed the remains to other, already known groups of animals. After all, those early discoveries were not of complete skeletons or even skulls, which would have revealed right away that the bizarre canines of sabertooth cats fit into an otherwise catlike skull and skeleton. Instead, the partial finds were like pieces of a jigsaw puzzle with no complete picture to refer to. One of the first people faced with the task of interpreting sabertooth fossils was the nineteenth-century Danish naturalist P. Lund. In the 1830s, Lund devoted a lot of time and effort to exploring the caves of Lagoa Santa, in the Brazilian region of Minas Gerais. He had left Denmark in 1833 (at the age of thirty-two) to pursue botanical research in Brazil, but in 1834 he met his compatriot P. Claussen, a fossil collector who had worked in Argentina before coming to Brazil. Lund was immediately fascinated by fossils and paleontology, so he abandoned botany and moved to Lagoa Santa, then a village with fewer than five hundred inhabitants that was surrounded by numerous calcareous caverns, some of them rich in fossils . Many of the caves were actively exploited for saltpeter, with lots of fossils being destroyed in the process, so Lund set out to salvage as much material as possible (Paula Couto 1955; Cartelle 1994). With admirable dedication, he and his local assistants explored cave after cave, collecting over 12,000 fossils between 1834 and 1846. It was extremely hard work, but Lund’s fascination for the extinct fauna of Brazil led him through all the difficulties he encountered, and whenever he found a rich fossil site, his imagination was set aflame. One of his peak achievements was to find the first remains of perhaps the most spectacular sabertooth cat, the Pleistocene felid Smilodon populator. Lund’s first finds were just a few isolated pieces, and he thought they belonged to a hyena, naming the creature Hyaena neogaea in 1839. But in 1842, with the addition of a little more material, including a few more teeth and some foot bones, Lund–an adept follower of G. Cuvier, the father of comparative anatomy–soon realized that the predator actually belonged to the cat family. Lund was convinced that the numerous bones of large mammals that he found in the caves had been dragged there by big predators, which retreated to their dark dens to feed at leisure. The identification of Smilodon as the dominant predator of its time rounded out the scenario in his mind: Discovering Sabertooths Sabertooth 4 Regarding its size, this unique extinct carnivore rivaled the largest known cats or bears; the size of its canines is very much larger than in any species of carnivore, living or fossil. Judging by the dimensions of its foot bones, its body must have been heavier than that of any of the living felines, including the lion. It is evident that a carnivore of such size, armed with such formidable weapons, must have reaped abundant victims among the inhabitants of the ancient world. In fact, I found the remains of its prey in three different caverns, which included, without exception, great accumulations of bones of diverse animals, many of them of gigantic size . . . In view of the unusual form of the canines of this animal, I propose for its generic designation the name Smilodon (“tooth shaped like double-edged knife”). Its bloody deeds, whose memory still endures in the caves that served it as dens, doubtlessly qualify it for the specific name of populator, “he who brings devastation.” (quoted in Paula Couto 1955:7–8) Lund’s account is a fitting introduction for an impressive animal that no human being had seen in over ten thousand years, and that no one would ever see alive again. While his interpretation of the origin of the fossil accumulations in the Lagoa Santa caves as the result of the activities of Smilodon is now thought to be not quite correct, his assessment of the size and strength of the newly discovered creature was soon confirmed by the appearance of more complete remains. In 1846 he could proudly write: “I now possess nearly...