Last week I got a call from an old college friend of mine. Dan Cearley and I worked together a lot when I was a photographer for the Associated Press in Guatemala. Dan was, at that time, a forensic anthropologist working on digging up mass graves for a human rights organization.
Fast forward 10 years and Dan and I are again in a muddy pit, surrounded by bones. Only this time, they are the giant bones of an extinct Columbian Mammoth, found by a curious farmer in an artichoke field in Castroville, CA. The farmer was grading a wall for irrigation when his grader uncovered what he thought was granite. Being a curious and intelligent fellow, and knowing that granite does not belong in the coastal farmlands, he got off his grader for a closer look. By pure coincidence, this farmer had always been interested in bones, even as a child. He once toyed with going into archeology, but the tug of the family farm kept him in the fields. In short order, he recognized the porous white substance as bone and called the local university. Many farmers would have plowed this right under, recognizing the halt it would put in their work and planting while excavation work was under way. This fellow thought the experience of finally getting to live some of his childhood dreams was worth the potential hassle. Now he spends his days in the pit, carefully dusting off bones with sponge brushes, or straining buckets of dirt through a wet-screen searching for pieces of bone or tusk missed during the initial excavation and bringing his family through to share in the experience. His nieces were there taking pictures, cataloging bones and gathering material for what I’m sure, is going to be the best science project in the local 8th grade class. More details on Columbian Mammoths after the pictures.
Columbian Mammoths (Mammuthus columbi) are effectively “North American Mammoths.” M. columbi is thought to have evolved from an earlier Old World species: Mammuthus trogontherii (the Steppe Mammoth). In Eurasia the same ancestor, M. trogontherii, evolved into M. primigenius (the Wooly Mammoth), which later also migrated into North America.
The range of M. primigenius (the Wooly Mammoth) and the range of M. columbi (the Columbian Mammoth) overlapped in some areas of North America; but M. columbi extended as far south as Mexico and Nicaragua, while M. primigenius remained in the more northerly latitudes. For the most part, both of these species appear to have gone extinct some time around 12,500 – 9,000 years ago. However, researchers have become aware of several small remnant populations on Wrangell Island in the Bering Straits and also on the Santa Barbara Channel Islands; these populations appear to have continued for several thousand more years before they too became extinct.