A grey whale has swum the longest distance ever recorded for a vertebrate marine animal. This is evidenced by a study published in scientific journal Biology Letters. The whale probably traveled about 27,000 miles.
The animal was found in 2013 off the Atlantic coast of Namibia, in southern Africa. It was the first gray whale found in the southern hemisphere, writes National Geographic based on the study. It was then examined which route the animal must have travelled.
It took years of genetic research to determine that the whale originated from the Pacific Ocean. Two known populations of grey whales live in that ocean: an eastern group of more than 20,000 animals and a western group threatened with extinction by roughly 200 whales. Based on the DNA, scientists were able to determine that this animal was genetically closest to the whales in the northwestern ocean, to Russia.
The scientists believe that the whale has swum around Canada and then moved south through the Atlantic Ocean. Two other possible routes are not considered likely. One would have swam through the Pacific and under South America, the other by the Pacific Ocean, the Indian Ocean and under Africa.
These routes are unlikely because no observations have been reported there. Also because the whales feed in shallow waters, a journey through open oceans seems more difficult.
Why the animal swam half the world is not entirely clear. Scientists believe that gray whales are looking for new habitats because of the rapid decline in polar ice due to climate change. The animals can get lost.