Discoveries by Australian scientists about a rarely seen and unusual type of whale have sparked fresh warnings about the effects climate change could have in the world’s oceans.
Little is known about the pygmy right whale, apart from it is only found in southern hemisphere waters off Australia, New Zealand and South America.
But palaeontologists from Victoria now believe the whale once inhabited waters much further north based on their studies of rare fossilised remains belonging to the animal’s ancient relatives found decades ago in Japan and Italy.
When the fossilised skull was found in Okinawa and an ear bone in Sicily, scientists were puzzled about what whale they belonged to as they didn’t match any species in northern hemisphere waters.
A team of palaeontologists from Museums Victoria and Monash University recently confirmed both fossils belonged to pygmy right whales, raising the question of how these southern hemisphere dwellers washed up north of the equator.
“That whale has always been seen as a southerner just in the same way as you may think a koala belongs to Australia,” Dr Felix Marx, research associate at Museums Victoria and Monash University, told AAP.
Dr Marx and his colleagues believe the key lies with the Ice Age, which began more than two million years ago.
They argue in a paper published on Tuesday in the journal Current Biology that some pygmy right whales crossed the equator after the Ice Age began and glaciers spread from Antarctica.
But when the Ice Age ended, the waters around the equator would have been too warm for pygmy right whales to find food in and so those that were unable to move south died out.
Dr Marx said finding serves as a warning about the potential impact warming sea temperatures could have on the pygmy right whale’s distant relatives including humpback and blue whales.
He suggests that while the pygmy right whale could survive a further move south, many other species of whales living in both hemispheres might not be so lucky.
“One possibility is that these populations might go off their separate way and form new species,” Dr Marx said.
“Another possibility is one population might become small or more susceptible to disturbances and actually go the way of the dodo as it were, so it could also lead to more extinctions.
“What the Pygmy right whale shows us is these sorts of changes can have major impacts on where these whales occur and how different populations throughout the world interact with each other and what can happen once they become isolated.”
Among the few details known about the pygmy right whale are that it is the smallest of the baleen whales, it is the only one that can see in colour, and has strange overlapping ribs.
Dr Marx describes the mysterious species as the platypus of the whale world.
“No matter what you look at somehow that species is weird,” he said.