Advertisements
Feeds:
Posts
Comments

Posts Tagged ‘African wild dog’

dholes

We know that hybridization is a big thing in the genus Canis.  Indeed, scientists are still debating about the validity of certain species because some of the extant forms of wolf could very well be hybrids between gray wolves and closely related species. Everyone thinks that the large coyotes we see in the East are all coywolves, even though they don’t have that much wolf ancestry. but then we have very good genomic data that shows that coyotes and gray wolves really aren’t that different genetically.  We know that Ethiopian wolves were threatened with and still could be threatened with hybridization from domestic dogs, but we also know that getting dog genes into a wild canid isn’t always a bad thing. Wild gray wolves in North America got their black color variant from a single Pre-Columbian black dog that crossed into the population between 1,500 and 7,250 years ago in the Yukon or the Northwest Territories.

I have often wondered if we could detect hybridization that went on long before all these wolf-like canids truly diverged, and a recent paper in The Journal Cell reveals that hybridization has always been a feature of these wolf-like canids. Gopalakrishnan et al. compared the genomes of gray wolves, coyotes, domestic dogs, golden jackals, the African golden wolf, the Ethiopian wolf, the dhole, and the African wild dog to see if there was any evidence of hybridization in the lineages.

The authors found that the African golden wolf was actually a hybrid species that developed from gene flow between the gray wolf and the Ethiopian wolf, which likely had a much more extensive range in Africa than it does now.  The authors also found that the clade (which I think is actually a single species) that includes the dog, wolf, and coyote received genes from an unknown species of canid. The dhole and African wild dog have also hybridized in the past, probably because both the dhole and African wild dog once had ranges that overlapped in the Middle East or in North Africa.

The discovery of this unknown species is perhaps the most intriguing. The authors speculate that it might have been the dire wolf or the extinct North American dhole, but seeing that this species fairly close to the division between the dhole and African wild dog, I think a more likely candidate is Xenocyon lycaonoides.  This animal has been posited as an ancestor the dhole and the African wild dog, but a more convincing argument is that the African wild dog derived from Lycaon sekowei.  It is not clear yet what the dhole derives from, but it could have derived from Xenocyon or shared a common ancestor with it.

Xenocyon was the dominant wolf-like canid in Eurasia and Africa during the early part of the Pleistocene, but by the mid-Pleistocene, it began to become less common, and as its numbers dwindled, the diminutive wolf, Canis mosbachensis, began to fill its niche, eventually evolving into the modern gray wolf, which also led to the coyote and domestic dog lineages, as well as the hybrid African golden wolf.

Maybe, as the Xenocyon’s numbers dwindled, a few remaining ones hybridized with C. mosbachensis, perhaps introducing some genes from better pack cooperation and larger size that helped the smaller wolf fill the bigger canid’s niche.

The authors are clear that we need lots of ancient DNA from these extinct canids before we can engage in flights of speculative fancy, but seeing that this unknown canid was so close to the dhole, I think that this animal is a better place to look. Xenocyon might be a bit too old to find viable DNA in fossil remains, but it is certainly possible that we could find some.

So yes, hybridization has greatly affected the evolution of wolf-like canids in the modern era, but hybridization always has. Similar findings have been discovered in bears and various members of the cat family.  My guess is that virtually every clade will have had some of this going on, even if the current species do not hybridize.  Speciation happens, but chemical interfertility isn’t lost for quite some time after speciation. Gene flow continues on with related species, which continues to affect their evolution.

Yeah, evolution is a tangled bush that also has vines that reach out and grab adjacent and not so adjacent twigs.

 

 

 

 

Advertisements

Read Full Post »

P1050079

Man originated in Africa. The whole lineage of apes from which we and all the other human species descended was in Africa, a sister lineage to the apes that gave us the chimpanzee and the bonobo.

But man’s first domestic animal was not of Africa at all. The large pack-hunting wolf roamed the great expanses of Eurasia, and it was only when certain Eurasian hunters began to incorporate wolves into their societies that we began the process of domestication.

For nearly two million years, human ancestors and the ancestors of the wild dog lived throughout Africa.  There was never an attempt to bring these dogs to heel, and there was never attempt to reach out to that species.

The question remains of why African wild dogs were never domesticated, and part of the answer lies in their nervous nature. I am reminded of Martin Clunes’s A Man and His Dogs.  Clunes ended his two part documentary with a visit to Tony Fitzjohn’s African wild dog project, and at one point, Clunes is asked to pick up a tranquilized African wild dog, while making certain that the jaws are positioned well away from his body.  These dogs react and react quickly.

These dogs live as quite persecuted mesopredators in an intact African ecosystem that includes lions and spotted hyenas.  Yes, this animal that kills large game with a greater success rate than any other African predator is totally the underdog in a land so dominated by the great maned cat and the spotted bone-crusher.

Their lives must be spent hunting down quarry and then bolting down meat as fast as they can before the big predators show up to steal it.

The current thinking is the first African wild dog ancestor to appear in Africa was Lycaon sekowei. This species lived in Africa from 1.9 to 1 million years ago, which is roughly the same time frame in which the first human ancestors began to consume meat readily.  It was very likely that a major source of meat consumed by these ancestors came from scavenging.  Homo habilis has been des cribed as a very serious scavenger, as was Homo erectus.

Both Homo habilis and erectus were contemporaries of Lycaon sekowei, and one really thinks about it, these early humans would have been very interested in the comings and goings of the great predators. Of all the predators to drive off kills, it is obvious that a pack of wild dogs would be easier to drive off than just about any other predators that were evident in Africa at the time.

So for at least 1.9 million years, African wild dogs evolved knowing that humans of any sort were bad news.  They may have inherited an instinct towards antipathy toward humans, and thus, there never was any chance for us to develop relationships such as those that have been observed with wolves and hunter-gatherer people.

I think this played a a much bigger role in reason why man never tried to domesticate African wild dogs. One should also keep in mind that wolves in Eurasia were also mesopredators in that ecosystem. Darcy Morey and Rujana Jeger point out that Pleistocene wolves functioned as mesopredators in which their numbers were likely limited by cave lions, archaic spotted  hyenas, and various forms of machariodont. They were probably under as much competition from these predators as the ancestral African wild dogs were under from the guild of super predators on their continent.

What was different, though, is the ancestral wolves never evolved in an enviroment which scavenging from various human species was a constant threat, so they could develop behaviors towards humans that were not always characterized by extreme caution and fear.

We were just novel enough for wolves to consider us something other than nasty scavengers, and thus, we could have the ability to develop a hunting symbiosis as is described in Mark Derr’s book and also Pierotti and Fogg’s.

It should also be noted that African wild dogs do not have flexible societies. In wolf societies, there are wolves that manage to reproduce without forming a pair bond, simply because when prey is abundant, it is possible for wolves other than the main breeding female to whelp and rear puppies. These females have no established mates, and they breed with male wolves that have left their natal packs and live on the edges of the territories of established packs. In the early years of the Yellowstone reintroduction, many packs let these females raise their pups that were sired by the wanderers, and one famous wolf (302M) wound up doing this most of his life, siring many, many puppies.  I think that what humans did in their initial relationships with wolves was to allow more wolves to reproduce in this fashion, which opens up the door for more selective breeding than one would get from wolves that are more pair-bonded.

In African wild dogs, one female has the pups. If another female has puppies, hers are confiscated by the main breeding female and usually starve to death.

The wolf had the right social flexibility and the right natural history for humans form relationships with them, which the African wild dog was lacking.

 

 

 

 

 

Read Full Post »

The little AWD puppy robot is so cute!

Read Full Post »

bush dog

We often talk about the South American wild dogs. The South American wild dogs are a sister group to Canis and its allies, and in South America, evolution allowed dogs to go many unusual directions.

When the dog family phylogenetic tree was drawn from sequencing the genome of a boxer, I was amazed that it put the bush dog, which is sort of a wild version of the dachshund, as being a sister species to the maned wolf, which has very long legs.

There was actually a big debate as to where the bush dog actually fit. When I was learning about dog evolution as a child, I had books that told me that the dhole, African wild dog, and the bush dog were all closely related because of their trenchant heel dentition. One of their carnassials has a single, blade-like cusp that increases their ability to bolt shear meat.

The phylogenetic tree that was created from the dog genome sequence pretty much ended this discussion. The dhole and African wild dog were both found to be closely related to Canis, more so than the side-striped and black-backed jackals. The bush dog was with the maned wolf and the other South American canids, and the trenchant heel dentition was the result of convergent evolution.

End of story.

Or so I thought.

In 2012, a study was released that that was meant to update the divergence times with all extant carnivora. The researchers used large samples of DNA and other characters to determine when these animals diverged from each other. Some of these “other characters were things like vocalization and scent gland similarities.

Its phylogenetic tree for Canidae is similar to that in the aforementioned paper on the domestic dog genome, except that it greatly increases the divergence time between species. For example, it has the Urocyon foxes diverging from the rest of Canidae 15-16 million years ago, instead of the 9-10 million years that the dog genome paper found.  It also has the golden jackal and the coyote being sister species, and the wolf is not the closest relative of the coyote. We now know this is very much in error, and it probably comes from the non-genetic “source trees” that were used in the analysis. It has has the Tibetan fox as being related to the extinct Falkland Islands wolf, which happened because there are almost no genetic studies on the Tibetan fox. Both the Tibetan fox and the Falkland Islands wolf had kind of weird squared off bodies, though, and this type of analysis does use morphology.

It has the dhole as being closely related to the wolf, golden jackal, and coyote.

But it has the African wild dog splitting off much sooner from this clade, and what’s more, it has the bush dog as its sister species!

One should be skeptical of this finding, because of its use of so many non-genetic “source trees,” it is going to miss the problem that occurs so much with dog species. Convergent evolution and phenotypic plasticity run riot in the family, and it is really hard to figure out relationships between species using just morphology and behavior alone.

This would make a lot of sense if it were confirmed with better genetic studies. Bush dogs are very weird animals. They are the only South American canids that hunt in packs. They really don’t have a rich fossil record, and it is pretty hard to connect them to other South American wild dogs.

It is tempting that they might be something that weird, but we need more evidence.

If they really did turn out not to be part of the South American clade of wild dogs and to be closer to the African wild dog, it would be a real shocker.

But not entirely.

The questions that would arise from it would be how it evolved.  We have evidence of Xenocyon coming into North America. Xenocyon is traditionally thought of as the ancestor of the African wild dog and the dhole, but it may not be. But there is also evidence of dholes or dhole-like dogs that are actually closer to the AWD coming into North America and making it as far south as Mexico.

So maybe there is something to it.

But this sort of study does have its limits. It’s trying to morph both classical and molecular techniques for taxonomy, and those tend not to hold up very well.

But I still think it’s worth examining.

 

 

 

 

 

 

 

 

Read Full Post »

golden retriever wild dogs

Lilly the golden retriever has been enlisted to raise some African wild dog pups that were born at the Oklahoma City Zoo.

Despite their unfortunate name, African wild dogs are not feral dogs. They are a critically endangered pack-hunting canid that is closely related to domestic dogs, wolves, and jackals.

The African wild dog bitch that had these pups was too nervous to care for them properly, and the zoo staff decided to use a domestic bitch as a surrogate.

Lilly’s biological pup is definitely going to have some interesting adventures with her littermates. Lilly is a search-and-rescue dog, and her puppy is going to trained for that exact same task.

But for right now, she’s a playmate for some really exotic foster siblings.

golen retriever pups and awd pups

 

 

 

 

 

 

 

Read Full Post »

From NBC:

A young boy fell into an African painted dog [African wild dog or painted wolf] exhibit at a Pittsburgh zoo and was mauled to death by the wild animals, zoo officials said.

The child, about 3 years old, was with his mother visiting the Pittsburgh Zoo & PPG Aquarium when he somehow fell from a 14-foot-high observation deck into the exhibit at about 11:45 a.m. He was immediately attacked by several dogs and died, zoo President and CEO Barbara Baker said.

The zoo quickly moved visitors into buildings as animal keepers tried to coax the dogs into an off-exhibit area. Many of the 11 dogs in the exhibit moved away immediately, and several others were scared away from the child by the zookeepers. A remaining dog would not leave the child, and a Pittsburgh police officer shot the animal.

It’s a pretty sad story.

African wild dogs don’t normally attack people, but these are zoo animals that are in very unnatural conditions.

A little kid falling into the exhibit could stimulate a predatory response, as it likely could from under-socialized packs of domestic dogs.

 

 

 

Read Full Post »

Image

Read Full Post »

Older Posts »

%d bloggers like this: