Advertisements
Feeds:
Posts
Comments

Posts Tagged ‘elephant seal’

Amazing footage!

Source.

Advertisements

Read Full Post »

Source.

In both northern and southern elephant seals, only a few males produce offspring ever year. The bulls lay claim to a stretch of beach and then claim as many cows as possible.

And yes, it really must suck to be a cow elephant seal.  During this time of her life, she continually being herded by males much larger than she is. And never mind the mechanics of their reproduction. She is a large seal, but she is significantly smaller than the male.

If you’re an elephant seal bull, you must be big and nasty if you are to reproduce. Only one in ten males manages to reproduce. That is an astoundingly low number:

Source.

These selective pressures on the elephant seal species have resulted in a favoring of bull seals that are the equivalent of the most-used sire effect in many breeds of purebred dog.

The northern elephant seal nearly went extinct. Its population may have dropped to only 100 individuals. Today, there are 100,000 northern elephant seals, and because of their particular breeding arrangement, very few males pass on their genes every generation.

It is very similar to what has happened in many purebred dogs, and I’m sure that some will suggest that if the northern elephant seals are able to have a healthy population, then it should be okay to breed dogs in this fashion.

The problem with that logic is that we actually don’t know the full consequences of the extreme genetic bottleneck on the northern elephant seal. Because they lack genetic variation, it is possible that an epidemic or even a slight environmental change could prove disastrous for the seals.  In normal populations, genetic diversity means that some animals will have some resistance to potential changes in the environment or infectious disease. However, if all the seals are genetically quite similar, they may all be similarly susceptible to these problems, which means they could all die off.

Again, the fact that it hasn’t happened yet doesn’t mean that it can’t.

The other thing is elephant seals are under the pressures of natural selection. Dogs really aren’t. Really defective seals don’t live very long. They wind up in the bellies of orcas or great whites. Truly defective elephant seals don’t reproduce. With dogs, we can continue to select for defect, intentionally or unintentionally. We can select for a whole range of disorders and not even know it until a third the dogs in any given breed have them.  (That is only slight hyperbole.)

One of the delusions we have is that we think we can just selectively breed out disease without actually realizing that we’re dealing with a dynamic genome.  I’m not in favor of breeding dogs with disease. Don’t get me wrong.

But unless we look at the whole system that leads to an accumulation of these diseases, we are doomed to failure. It is quite literally little more than rearranging deck chairs on the Titanic to think we can just cull for this disease or that one and not realize that the problem is much more systemic than peculiar.

Nature has done what it can to save northern elephant seals. Considering how these animals breed, I would certainly have wanted to have started with a larger founding population than 100 to 1,000 individuals.

But we didn’t get that choice.

With dogs, we have that opportunity, but it remains denied to us, simply because we cannot change our thinking.

As I’ve said before, the human ego is probably the most destructive part of the relationship between man and dog.

We are the so-called rational species, and in this relationship, we’re supposed to be the responsible ones.

But for all of our intelligence, we have failed our dogs.

And it’s something we need to think about.

Read Full Post »

Actually, especially if it’s  in the water!

The diver who got attacked said “It looked friendly.”

Um.

I’m not expert in elephant seal body language, but if I saw a dog with that expression on its face, I don’t think I’d be petting it!

Read Full Post »

%d bloggers like this: