Scientists may have found a fully preserved pygmy mammoth tusk on Santa Cruz Island. With its help, it is possible to establish how the mammoths, cut off by the rising sea from California, became smaller and died out
Scientists suggest that mammoths, whose growth was then more than 4 m, swam from the mainland to the islands about 20 thousand years ago. Perhaps they were attracted by the rich pastures. Later, due to rising sea levels and harsh living conditions, mammoths changed and decreased significantly in size.
Previously, scientists have found the remains of mammoths in large numbers on the islands of San Miguel and Santa Rosa. But on the island of Santa Cruz, such discoveries were rarely made, since its relief for the life of mammoths is not suitable - mountainous terrain and very little grass, which means limited food supplies.
“This is the most important and significant mammoth finding on Santa Cruz Island,” said Lotus Vermeer, head of the Santa Cruz Island Nature Conservancy.
Finding the tusk
According to Vermeer, the tusk was accidentally stumbled by archaeologist and graduate student of the University of California (Santa Barbara) Kristina Gill (Kristina Gill). She worked in the northern part of the island.
“I studied the geological structure of the area, looked up. Then she turned her eyes down to take a step, and almost stepped on the tusk, - said Jill. She looked carefully and found traces of other bones in the sandstone. Jill photographed all this and showed the pictures to specialists. The photographs were examined by Larry Agenbroad, director of the Mammoth Site of Hot Springs in South Dakota. From the photographs, he determined that among the bones found there is a tusk, several ribs and, possibly, a mammoth's thigh.
However, other experts who saw these photographs disagreed with Eigenbrod's findings. Paul Collins, head of the vertebrate department at the Santa Barbara Museum of Natural History, noted that this "tusk" looks more like the jawbone of an extinct whale. He also noted that the hardened sandstone in which the bones were found is a characteristic environment in which the remains of marine animals are most often found.
The theory of the appearance of dwarf mammoths
Santa Cruz is the largest of the eight Channel Islands located in the Pacific Ocean. Its area is 245 sq. km. Scientists believe that in antiquity the islands of Santa Cruz, San Miguel and Santa Rosa were one with the island of Acanapa. This huge island was located just off the coast of modern California. Scientists named it Santarosae.
According to paleontologists, mammoths living on the territory of the American continent swam across the Santa Barbara Strait during the Pleistocene, when sea levels were lower and Santarosa Island was only a few kilometers from the mainland.
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After several centuries, the sea level began to rise gradually and soon reached the present. As a result, the mammoths were completely isolated from the mainland. The island could provide only a limited amount of food, so in the struggle for survival, mammoths began to adapt to local living conditions. Gradually they became much smaller and more agile.
Until now, the most important finds on Santa Cruz Island have been the tusk found in 1985, as well as a portion of the thigh and humerus found in 2005. However, they belonged to ordinary mammoths living on the American continent. But the recently found tusk is small enough, that is, it could well belong to a dwarf mammoth.
In addition, scientists have discovered for the first time the remains of a mammoth in the mountainous area of Santa Cruz Island. All previous finds have been made in the southern region.
Subsequent research
If the assumption of archaeologists about the tusk is confirmed, scientists will try to determine the exact age of the find using the radiocarbon method. Previous research has suggested that humans first appeared on the island at a time when there were a lot of mammoths. If so, then the animals could well have been exterminated by primitive hunters. The oldest evidence of human activity on the island is 13,000 years old, and the latest mammoth skeleton is 12,800 years old. Jill was just studying traces of human activity in the mountainous regions of the island when she accidentally discovered a tusk in the gorge.
The Nature Conservancy has invited Eigenbrod to take part in excavations starting next week. This specialist has already worked on the Channel Islands. In 1994, Eigenbrod took part in the restoration of the almost completely preserved skeleton of a dwarf mammoth found on Santa Rosa Island.
After the end of the excavation and the extraction of the bones, they will be transported for further study to the Museum of Natural History of Santa Barbara, whose staff will also take part in the expedition.