Wednesday, July 23, 2008


I was watching a program the other night on marine animals. There was amazing footage of whales, dolphins and porpoises, full-time marine mammals (known scientifically as cetaceans), but they also covered polar bears and sea otters, penguins and other diving birds. I knew that polar bears have received special recognition of their unique life style – their official taxonomic name is Ursus maritimus, or Sea Bear – but I didn’t know the great distances they routinely swim at sea in search of food. And now that the Arctic is melting, they are being forced into swimming even greater distances, exhausting themselves to the point of drowning. It got me thinking about the whole process of evolution.

Sea bears, like everything else on the planet, are not staying the same. Evolution isn’t something that happened once a very long time ago, and it isn’t over yet. As a birdwatcher for almost 40 years, I’ve seen several editions of field guides come and go. As more is learned about distribution, hybridization, and DNA, certain species and subspecies are constantly being reshuffled. The Yellow-shafted and Red-shafted Flicker used to have separate listings, but are now grouped together as the Northern Flicker, because where their ranges overlap, they hybridize. And in the southwest, the Red-shafteds will hybridize with the local populations of Gilded Flickers, who still do have their own listing. For now. Things can change, so it’s best not too get to comfortable with anything. When I was a kid in Michigan, we had Baltimore Orioles. A couple of decades or so later, Baltimores and the western Bullock’s Oriole became the Northern Oriole. And most recently, we’re back to two separate subspecies again. As far as planet earth is concerned, nothing is carved in stone. Except the mountains.

So, all this information leaves a question or two about the future. Polar bears as we know them today evolved about 250,000 years ago, and they did it rather more rapidly than might otherwise have been expected. But now that the Arctic is melting so fast, will they be able to do it again? Assuming we can get our collective global act together and not totally ruin the planet, where will Ursus maritimus be in another quarter-million years? Will they have become like the cetaceans – land mammals that returned completely to the sea? Will they be swimming along with strange sleek creatures slightly reminiscent of otters and penguins, which also must surface to breathe air through a blowhole? Only time will tell.

Well, after writing this, I feel like taking a break and watching a movie. How about Kevin Costner in Waterworld.

Photo of Sea Bear from Wikimedia Commons


Indrani said...

I appreciate your concern for these beautiful animals and I enjoyed reading this informative post. Nature is changing at a rapid pace and most often we can just watch mutely.

I liked your blog name too. Sad I haven't read this great book yet.

Thank you very much for your comments at my 'frozen moments'. I invite you to visit my other blog 'i Share' too whenever you get time. :)

Anonymous said...

All so true, and kind of scary, isn't it? Good choice of movies! I like anything with Kevin Costner.

Poetikat said...

Deb - we have just recently got ourselves a new 37" HDtv with satellite programming and the greatest joy as a result of that decision is a channel called OASIS. Therein we find programs about wildlife, flora, landscapes and countries - we are held captive daily. If you can possibly do it, I recommend getting hooked up to this - the armchair experience as well as the education is incomparable!

Having said that, I learned a great deal from your post. Thank you.