Advertisements
Feeds:
Posts
Comments

Posts Tagged ‘dog’

Source.

This is my favorite zoo, BTW.

Advertisements

Read Full Post »

4 million

high point

According my stat counter, this blog will have crossed the 4 million hit mark within the next hour or so.

Thank you for reading, sharing, and subscribing to my work.

It’s been a lot of work. I have put my heart and soul into this project over the years.

I’ve learned a lot.

And I appreciate you for indulging me.

Read Full Post »

A spotted hyena pseudo-penis. Source for image.

A spotted hyena pseudo-penis. Source for image.

I woke up this morning to check the comments on the blog. I normally do not close comments for older posts, and I often forget about the posts I wrote several years ago.

Some of them have never generated particularly good comments, and this particular one, which is not particularly profound or well-writen, is simply entitled Hyenas are not dogs. They are actually more closely related to cats.

The comments on there are pretty picayune and banal. The post was pretty picayune and banal, so what else would I expect?

Well, when I woke up this morning, I came across this gem, which I have to say is the worst creationist argument I’ve ever seen!

Here it is in all its glory:

Sorry, Hyenas are dogs. I do not care what you say. Evolution is a theory and has never been proven. Hyenas are not cats, and are not related to ferrets, weasels, civets, are any other animal. They are dogs plain and simple. If it looks like a duck and it quacks like a duck its a duck. Weasels, ferrets, civets, mongoose etc., do not look like dogs. Rest my case. Hyenas are dogs.

I hope this person is just acting a Poe.

It’s hard to tell with these creationists though. It really is.

I am having a hard time reading it without having blood vessels pop out.

First of all a ferret or a weasel is a Caniform Carnivoran. Caniforms are all closely related to dogs, though they are much closer in resemblance to primitive Caniformia than Canids (“the dog family”) are. The fact that they look like mongooses is really quite irrelevant.

Secondly, spotted hyenas look nothing like dogs, and only a really superficial examination of striped and brown hyenas would lead one to believe that they are anything like a dog. I know that the German and Afrikaans-speaking settlers to southern Africa called the brown hyena a “strandwolf.” The term means “beach wolf,” which is in reference to the ubiquity of brown hyenas along the Skeleton Coast, where they scavenge flotsam and jetsam and sometimes hunt fur seal pups. They were called wolves for the same reason that the same people called a giant antelope a moose. The eland antelope species of Africa are actually named after the Dutch/Afrikaans word for moose, which is eland. And it wasn’t just the eland antelope. Gemsbok, a type of oryx, share the same name with the chamois of Europe. Steenbok is the Dutch name for the Alpine Ibex. Rhebok are named for the Dutch/Afrikaans name for the European roe deer.  All of these animals antelope, but none of their European namesakes are.

They also called the spotted hyena the “tiger wolf.”

But people giving animals inappropriate common names is pretty common in just about every language. What we call a moose, the Europeans call an elk. What I call a robin is more closely relate to a European blackbird than to the European robin.

So ignore the names.

Let’s talk phylogeny.

Dogs and hyenas really don’t look that much like each other. All living species of hyenas, except the aardwolf (another misnamed “wolf”), have evolved a bone crushing capability in their jaws that no living dog has. However, in North America, there were once dogs that had this bone crushing capability. These dogs, called the Borophaginae (“bone crushers” or “bone eaters”) live between 36—2.5 million years ago in North America. Some of them were giants, and many were quite well-adapted eating the bones of megafauna.

No living dog is a true bone-eater. They will eat bones, but they will never crush them with efficiency of any species of hyena or one of those Borophagine dogs. (If you want to find out more about the evolution of bone crushing in Borophaginae and hyenas, check out this lecture at the Royal Tyrell Museum. It’s very fascinating.)

Then there is the DNA. We’ve been able to construct phylogenetic trees based upon genetic material. Every study that has examine Carnivoran DNA has placed hyenas with the Feliformia. They are most closely related to the true civets, which is the family Viverridae. They did evolve into something like a dog, and if you watch that lecture at the Royal Tyrell Museum, you’ll see that more primitive forms of hyena actually looked a lot more like dogs than modern ones do.

When phylogenetic trees are drawn from DNA samples, dogs fit with bears and seals (and the walrus and “eared seals”).

Hyenas and dogs are out of two entirely different lineages that split about 42 million years ago.

The fact that they superficially look alike is not evidence of a common designer at all.

The big difference between dogs and spotted hyenas in particular is their social structure. All dog societies, save domestic dogs and some red foxes, are base upon a mated pair in which there are no great size or phenotypical differences between males and females. In spotted hyena societies, the females are larger and have dominance over the males. Status is inherited from mother to daughter, which does not happen in any species of dog.

And one way the females maintain their dominance is through a fluke in their anatomy. Female spotted hyenas have genitalia that strongly resembles a male’s penis, but it’s actually the clitoris. And it’s through this tube that female spotted hyenas urinate, copulate, and give birth through this pseudo-penis. Female hyenas have absolute control over mating because they can move this “device” to prevent copulation. All a female dog can do is sit down with her tail between her legs and growl.

No dog species has this feature.

The only other mammal that has anything like this is the fossa of Madagascar. It is sort of a mongoose that became a cat. The females of this species are born with a pseudo-penis that becomes a “normal” clitoris as the animal mature.

Fossas were once thought to be civets, but like all Malagasy carnivorans, they are now believed to be more closely related to mongooses.

But it really doesn’t matter. Both mongooses and civets are Feliformia, as is the hyena.

And it does point to common ancestry, even if the rest of their relatives do not have this feature.

A spotted hyena is not a dog with a pseudo-penis.

This same argument if taken even further would lead one to believe that a thylacine was nothing more than a wolf with a pouch on it.

Thylacines looked a lot like wolves. (See this page at the Thylacine Museum to see how similar they were). Even trained anatomists have mistaken thylacine remains for those of wolves.

They actually looked much more like dogs than hyenas do.

And they are absolutely not related to dogs at all!

They are most closely related to either the quolls, which look like miniature arboreal thylacines, or to the numbat, which looks like a thylacine that evolved into an anteater. (It eats nothing but termites, but it has the anteater’s long tongue!)

These animals are all marsupials. They share no close ancestors with dogs or anteaters or cat or any placental mamals at all.

The split between placental and marsupial mammals is even more distant– at least 125 million years ago.

Why do they look the same?

Because natural selection required that these animals evolve similar bodies to fill somewhat similar niches. (Though it should be noted that thylacines actually did behave more like big cats than wolves.)

Believe it or not, this dog-like form has evolved several times in the past. Not only do we have the aforementioned dog-like hyenas and the thylacine, but there was once a crocodilian that looked very much like a hairless coyote.

By this creationists’ logic, all these animals would be called dogs.

And they aren’t at all!

Yes, I do know I used scientific terms for female genitalia, which I know creationists like are icky.

But seriously, how dumb can you be!

 

 

 

Read Full Post »

Canis lupus familiaris:

dog with wolf shadow

Read Full Post »

Dave sent me a link to this study in Heredity that looked a major histocompatibility complex (MHC) variability in domestic dogs.

It found that dogs were so diverse in the MHC in their haplotypes that there had to have been at least 500 wolves in the founding population.

It included 128 Asian dogs in this analysis, and it found that Asian dogs had greater diversity in European dogs, and of course, this leads to people crowing about evidence of an Asian origin for the domestic dog.

Not so fast.

MHC haplotypes have generally been lost as Western dogs have become breeds, and they continue to lose them as popular sire issues stratify the already closed gene pools.

Asian dogs, whether they are construed as breeds or not, have not already undergone this process. Or if they have, they’ve done it for very long.

I am not skeptical of the notion that lots of wolves were used to found the population that became modern domestic dogs.

I am, however, quite skeptical of the hypothesis that dogs originated in East Asia.

It’s much more likely that this was a long process that involved many wolves over a long period of time.

And it happened in many different parts of Eurasia.

Further, it’s also very likely that the dog lineages we have now are but remnants of what once existed. We’ve likely lost y-chromosome and mitochondrial DNA lineages,  as well as MHC haplotypes, and because we’re looking at only what exists now, it is actually something a dubious undertaking to try to divine dog origins in this fashion.

We are trying to read backwards through using living dogs, but what we really need are studies of DNA samples from very old specimens– which are not easily procured.

I think the process is likely much more complex than we might like it to be, and it had to have involved the agency of both certain wolves and humans. Without both species exhibit some sort of agency, there would be no domestication of the wolf.

Black-backed jackals have scavenged off of man for a very long time. They have lived in our cities and camps. And they are no black-backed jackals with floppy ears and spots and all the other features we associate with domestication.

For decades, people have looked for simplistic answers to the question about how wolves became dogs.

They’ve not found them.

We’re talking about two species that have pretty complex behavior, and to try to reduce them into a grand theory of domestication is probably not the best way to proceed.

It’s likely far more complex than we can understand at this time (if we can ever understand it at all).

 

 

Read Full Post »

Barn owl doesn’t like dogs

And the owl freaks the little poodly dog out. Big time.

Source.

I’ve always thought barn owls were cool, even though they are not found in my part of the country.

 

Read Full Post »

This is a coyote, but it obviously has a dog somewhere in its ancestry.

We have a name for these particular white markings in domestic dogs. It is called Irish spotting or Irish markings.

No wild canid has this coloration. The existence of these markings is indicative of domestic dog genes within a wild population.

This coyote got likely its white markings from a dog ancestor that bred with a female coyote. The hybrid was fertile and had enough coyote characteristics to survive in the wild and mate with another coyote.  The dog ancestor is likely several generations away, for this animal really looks very much like a coyote, just with unusual markings.

These particular white markings are very hard to get rid of in domestic dogs, and it is likely that they are very hard to lose within coyote populations once they are introduced into the gene pool.

And you still doubt the studies about the black wolves getting their coloration from the same source?

If you can get Irish markings from dogs, you can get also get black color from them.

It’s really that simple.

 

 

Read Full Post »

Older Posts »

%d bloggers like this: