Problems in the Land Vertebrate Zoogeography of Certain Islands and the Swimming Powers of Elephants
Johnson DL. 1980. Problems in the Land Vertebrate Zoogeography of Certain Islands and the Swimming Powers of Elephants. Journal of Biogeography. 7(4):383-398
The presence of fossil elephants on certain islands off California, in the Mediterranean, in Indonesia, and off China has led to two widely accepted assumptions: (1) that elephants, being poor swimmers, could not have swum to the islands and therefore must have walked to them, which indicates that (2) land bridges once joined the islands to the mainland. These two assumptions have profoundly influenced various insular biogeographic and geologic reconstructions on and around these islands. New evidence, however, shows unequivocally that living elephants are excellent distance swimmers. They swim in a lunging, porpoise-like fashion while using their trunk as a snorkel. Elephant swimming speeds have been measured up to 2.70 km/h, and maximum distances estimated at 48 km. Their chief motives for swimming seem to be that they can see the islands and smell food on them. Because elephants are excellent distance swimmers, we must re-appraise the origin of land vertebrates on all the islands that held elephants, as well as reappraise the geologic reconstructions that assumed land bridges once connected these islands to the mainland.
- Type
- Journal Article
- Authors
- Johnson, Donald
- Units
- CHIS
- Keywords
- Channel Islands CA, land bridge theory, Paleontology, Pygmy Mammoth (Mammuthus exilis)