150,000 years ago: During the past two ice ages, researchers believe Columbian mammoths swam to the Channel Islands.
Once there, the population grew and sea levels rose, leaving the mammoths little incentive to leave or stay big.
A much smaller mammoth emerged, now known as the Channel Islands pygmy mammoth. Researchers said that evolution could have happened in just several thousand years.
For more than 150 years, people have uncovered clues about the mammoths and their lives on the islands.
- 1959: Human remains were found on Santa Rosa Island that were about 13,000 years old. The Arlington Man is believed to be the oldest human skeletal remains found in North America.
- 1994: A nearly complete skeleton was excavated on Santa Rosa Island. One of the earliest pygmy mammoth fossils, it dated back about 12,900 years.
- 2013: The oldest, well-dated pygmy mammoth found on the Channel Islands also was discovered on Santa Rosa. The tusk was about 80,000 years old.
- 2014: A mammoth tusk was spotted in a canyon wall on Santa Rosa Island. During the excavation in September 2016, a team said the tusks and a complete skull seemed bigger than a pygmy but smaller than Columbian.
