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Glyptodont (Wikipedia photo)
By Gary Every
Special to the Crier
Who would have thought that Safford, Arizona was currently glyptodont headquarters for the world? Some of you may be wondering exactly where is Safford, Arizona? But I bet many more of you are wondering what a glyptodont is? A glyptodont is a prehistoric relative of the armadillo who roamed North America during the Ice Age. Glyptodonts were much more heavily armored than armadillos and considerably larger. An adult glyptodont was roughly the size of a Volkswagen Beetle automobile and counting the heavy turtle like shell known as carapace – weighed approximately one ton. On January 14th, 2013 I attended a lecture hosted by the Museum of Northern Arizona and presented by David Gillette, titled Mammoths, Saber Cats, and Glyptodonts – Beasts of the Ice Age.
Gillette began his lecture with the slide of a giant mammoth skeleton replica in a museum. Gillette described how surprised he was to step inside the museum in Fort Hays, Kansas and see the giant mammoth on display. It was a replica of a mammoth which Gillette had helped excavate many decades before in Utah. This particular mammoth still holds the record as the largest ever unearthed. He must have been a large bull about sixty-five years of age when he died. This mammoth also holds the record for being discovered at the highest elevation of any mammoth ever unearthed.
Gillette told us of other memories from that long ago Utah dig. For instance, the night watchman had absconded with the skull of a short faced bear. The watchman believed he had stolen a saber toothed cat skull and could not resist the temptation to bring his buddies home from the bar and show them the ill-gotten prize he had stored in his refrigerator. This proved to be his undoing and soon authorities had raided the watchman’s house and refrigerator, recovering the short faced bear and several other stolen artifacts that had disappeared from the worksite.
Gillette explained that 10 million years ago South America was an island continent but the flora and fauna of South America at that time were more closely related to Australia than anywhere else. The beasts of North America were more closely related to the creatures and plants of Eurasia – land bridges such as the Bering Strait connecting the continents as often as not. About five million years ago the continents of South America and North America collided, connecting at the Panamanian isthmus. Animal species which had never met before began to mingle as they migrated north and south. Species which we associate with North America such as the mammoth, travelled deep into South America. The first humans on the continent migrated along with the herds, hunting them on their long slow migrations. When the continents were first connected by land bridge, South America only had one dominant predator – the ferocious terror bird. Terror birds were a definite link in the lineage between dinosaurs and birds. They were certainly living the legacy. Terror birds are best described as swift giant carnivorous ostriches who hunted in packs.
To protect themselves, some herbivores became giants. Glyptodonts were one of many varieties of giant armadillo – all of them big and heavily armored. One species even had a spiked tail which it could wave in battle like a mace. As they migrated into North America the South American animals ran into a murderer’s row of fearsome predators. North America had several types of bear, dire wolf and his brethren, a cheetah, an American lion a hundred pounds heavier than his African counterpart and all sorts of saber toothed cats. A family of cats rather than a single species, saber toothed cats included the mighty smilodon and the scimitar cat which specialized in hunting mammoths.
Dr. Gillette did his dissertation on a glyptodont excavated near the New Mexico/ Arizona border which had two large puncture holes in his head, no doubt from a saber toothed cat. The feline hunter probably jumped on the back of the giant herbivore and bit his brain. Glyptodonts were among the animals which migrated into North America from South America. They came up as far north as Albuquerque before turning east and following the gulf coast. During the Ice Age, ocean levels were much lower and the giant lumbering glyptodonts were able to graze far and wide along the exposed continental shelf, traveling all the way to Florida.
When I posted on my Facebook page that Safford was the hotbed of glyptodont excavation worldwide, one of my friends wittily replied, “If you have ever been to Safford you would know why things went extinct there.” While this was a funny retort, it is not true; I am rather fond of Safford, Arizona. For one thing the Gila Box Riparian zone is just outside of town and a wonderful place for hiking, complete with an observation deck on a cliff overlooking the creek for bird watching. The glyptodont excavation site is the other direction from the town amidst the vast expanse of creosote. This long flat sandy expanse sits on top of the remains of a prehistoric Pleistocene lake.
After an explosive volcanic event (we don’t know exactly where the volcano was) a large amount of ash was blown into the vicinity of what would someday be Safford, Arizona millions of years later. When the ash fell on the lake it sank to bottom in a nice even layer of sediment. The glyptodont fossils are being discovered in this sediment layer. What is fascinating is that not only are the one ton glyptodonts nearly perfectly preserved but they have all been discovered on their backs. Gillette theorizes that the glyptodonts all died from the volcanic catastrophe which laid down the layer of ash. Already on the lake, when their corpses bloated with gas the dead glyptodonts became light enough to float, one ton carapaces floating on their backs. When the gases burst, the corpses exploded and sank to the bottom of the prehistoric lake where future layer of sediment preserved the skeletons as fossils. Gillette described this process that began with a volcanic cataclysm as “bloat, float, and explode.” As he ended the lecture Gillette was proud to show us photos from a visit by a BBC film crew shooting pictures of the glyptodont excavations for use in a documentary on the subject of climate change which will be narrated by Alice Roberts.
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