Wild Facts

Yesterday we talked about the Jackal which as we learned is a member of the canine family.  Today’s animal is known as a “Sea Dog” but don’t let that name confuse you since the Harbor Seal is in no way shape or form related to the jackal or any other canine for that matter.

The harbor seal is known as a “Sea Dog” since they look like earless dogs when they stick their head out of the water.  The thick coats of the harbor seals tend to be greyish colour with black spots or rings.  Even though the harbor seal moults yearly, these markings will remain and are unique to individual seals.  Most of the darker colours will appear on the backs of the seals as with most marine mammals.  This is a defense mechanism so they blend in with the water when looked at from above.  This camouflage will play tricks on the visual predators. Don’t worry, you will still be able to spot them on your ocean cruise while they are sunning themselves on the rocks.

Harbor seals are excellent divers and have something called a dive reflex. This dive reflex is activated the second the seal submerges its head and automatically causes the seal to hold its breath, slow its heartbeat and even reduce the amount of oxygen being delivered to all organs except the brain and the heart.  This dive reflex works so well that the seal is even able to sleep underwater and subconsciously coming to the service for oxygen throughout their slumber.  Imagine how much of the ocean floor you could see if scuba divers had this dive reflex?

I have provided a short video clip that shows the beauty and grace of the harbor seals underwater.  Notice their flippers as they swim.  It is interesting to note that seals are pinnipeds (as are walruses) which is a group of land animals that returned to the sea.  Obviously, this didn’t happen over night but it is still interesting to note some of the unique characteristics that would be reminiscent of a land animal.

Enjoy the video!

Literature Cited:

http://www.northwestwildlife.com/articles/harbour_seal.pdf

It is time for another fact!  I want all of you to pay attention today since I will be asking for input on something at the end of this fact.  Anyone who answers will get one Wild Fact Bonus Point! I wanted to take a trip up north today and talk about the hooded seal.  More specifically, I wanted to talk about the male hooded seals since the females do not have this adaptation.  So what is the adaptation?  Well, adult male hooded seals are able to inflate a sac that can cover their head.  See, they have this pouch, which is an extension of their nasal cavity, that hangs down below their eyes and over their upper lip. By closing both nostrils and blowing the hooded seal has the ability to blow this ballon-like structure to a size similar to a basketball. Believe it or not this isn’t their only talent!  The males are also able to close off one nostril and blow this balloon out of their nose.  Could you imagine how great these animals would be for blowing up balloons at your kids 6th birthday party!

The million dollar question is why do the males have this adaptation? Sure it looks weird and would probably be fun to play with but is there something more to it? In a book by Judith E. King titled Seals of the World she observed the seals just floating around on the ice blowing up the balloons just to deflate them.  This seems like it might be something that entertains them.  I know if I had the ability to blow a balloon from my nose that I would constantly be taking advantage of this party trick!

To me a more reasonable explanation as to the purpose of these sacs has to do with social dominance.  They are similar to the massive racks on bull moose.  It is known that the male hooded seals will inflate these sacs if they are threatened and again to warn other seals to back off during mating season. So not only are they tons of fun but they also serve a purpose to warn off potential threats.

I promised that I would ask a question at the end of this fact so here it is.  What could these sacs be used for other than social dominance and just for fun? They may serve a purpose in the water, however, we hardly observe seals in the underwater world.  You will get a Wild Fact Bonus Point if you answer and the best answer gets an additional 5 Wild Fact Bonus Points.

Hooded Seal Fast Fact: The male hooded seal does not develop this special sac until they reach 4 years of age.