May 22, 2014
Discovering All Things Whale
Who does not like whales? Well, Jonah might not, I guess. These gentle, majestic giants have roamed our seas for thousands of years and for much of that time have been greatly admired by man. Admittedly, they were often admired for their blubber and other things that whalers could get from them, but fortunately modern sanctions against whaling have allowed their once dwindling populations to recover somewhat, and it’s a good thing, too, considering how much we are still learning about these incredible marine mammals. Take the humpback whales of the North Pacific, North Atlantic, and the Southern Hemisphere. For the longest time, these whales were all thought to be the same and merely living in different parts of the world. Recent studies have defied that by classifying these animals as different subspecies from one another.
By using genetic samples that were taken from free-swimming whales using a small biopsy dart – a method that is said to cause these enormous animals no real pain whatsoever – researchers from the British Antarctic Survey and Oregon State University were able to study two various strains of DNA. The first of these was the mitochondrial DNA, which is inherited from the mother, and the second being the nuclear DNA, which comes from both parents. The mitochondrial DNA was used to create a genetic picture of how female humpback whales move across the globe now and over the last million years, while the nuclear DNA was used to paint a picture of a general pattern of the species’ movements as a whole. What they found was that, although humpback whales have the longest migration of any mammal as they travel between their summer and winter feeding grounds — almost 10,000 miles apart — these three groups of humpback do not actually cross paths with each other, which has created very distinct genetic differences between them.
Apparently, though female humpbacks have crossed from one hemisphere into another at some points in the last few thousand years, most will actually stay in their ocean of birth for the whole of their lives. What this means is that these three groups of humpbacks have been evolving somewhat independently for all of that time. This is what has led to the classification of them as three distinct subspecies and could have serious implications on both conservation efforts and the recovery of their populations as a whole, changing the focus from global to regional. This should come as welcome news to all the whale lovers out there, as this could and likely will mean improved effort in preserving all three distinct subspecies.
Studying these fascinating animals has given researchers a unique perspective on the oceans of the world as they were thousands of years ago through the lens of the whale’s migration patterns. Thanks to the improved conservation efforts that have helped humpback whales fight back against over-hunting and potential extinction, these marvelous creatures are still swimming around out there today and providing us with that lens. So, while the discovery of the three unique subspecies may not be seen in the same light of importance as finding cures for cancer or the invention of advanced artificial limbs, it remains a significant one. Knowledge of this world and the many creatures we share it with is an important foundation for their conservation. The more we know, the more we care.
Image Credit: Thinkstock