Just a fox on a leash

Clive out for a snowy stroll.

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Clive snuggled in on a cold winter’s day

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The strange hybrid between a pheasant and a “blue grouse”

Dusky grouse hen.

Hybridization between animal species is a topic that has long fascinated me. I’ve been looking at various animal hybrids over the years, and some are really quite shocking. Marine mammals produce all sorts of weird hybrids, as do birds, and in it is in the avian world that I came across the strangest hybrid.

Only a few of these hybrids have ever been reported, but a few hybrids between “blue grouse” and common pheasants have been reported.  I should note that these “blue grouse” and pheasant hybrids have mostly been documented before the molecular revolution in biology and no DNA studies have ever provided proof that these weird birds were indeed hybrids between the two species.

Also, these hybrids were described before the “blue grouse” was split into the dusky and sooty grouse. The dusky and sooty grouse are estimated to have last shared a common ancestor 240,000 years ago and have been given distinct species. The sooty grouse (Dendragapus fuliginosus) is found in conifer forests along the Pacific Coast from the Yukon to California, while the dusky grouse  (D. obscurus) is found at similar forests in the interior mountains of the West.

These grouse are highly specialized to life in conifer forests. The breeding behavior of both species of grouse involves the cockbirds hooting from way up at the top of big conifers to draw in hens.

Compare this bird with the common or “ring-necked” pheasant (Phasianus colchicus). This is an introduced gamebird that, although found in Western Europe, is native from the Caucasus into East Asia. This a grassland species that has social and breeding behavior that is quite similar to domestic chicken. Indeed, these birds are quite closely related to the jungle fowl of South Asia, and sterile hybrids between chickens and pheasants are not uncommon.

The common pheasant is a grassland specialist. This bird was heavily introduced to the Midwestern and Eastern US as a gamebird, and now that the forests have largely taken over vast swathes of farmland, the birds are far less common. For example, West Virginia now allows only a single male pheasant to be taken every day during the pheasant season, while Ohio allows only two for the daily bag limit.

So pheasants are a creature of the grassland and dusky and sooty grouse are creatures of the big conifer forest, it is quite surprising that these two birds would ever encounter each other, much less make a hybrid.

One hybrid was described in 1955. It was likely the result of game farm pheasants crossing with a dusky grouse in Eastern Washington State:

So by 1955, four these hybrids have been documented. However, this discovery was documented at roughly the same time Watson and Crick discovered DNA, and no one had any way to confirm this hybrid origin using molecular techniques. I have not heard of any other hybrids between these two species since this one from Spokane County, Washington.

These forest grouse and these grassland pheasants are so distinct from each other. However, I do know from my own observation of gallinaceous birds that the males of these species are pretty amorous. They will try to hump whatever they can, and a female pheasant sort of looks a lot like a dusky grouse hen.

My guess is this specimen described in the 1950s was the result of a male dusky grouse mating with a farmed pheasant. Only one poult managed to hatch out from the mating, but the poult imprinted upon its  pheasant mother. When it went looking for others of its kind, it wandered over to pheasant farm and tried to join what looked and sounded like its mother.

These hybrids are not something that one would expect to see in nature, but because man is constantly breeding and stocking pheasants to fit the needs of hunters, there could always be a chance for some intrusion of the pheasant into what is really much more suitable sooty or dusky grouse habitat.

Grouse and pheasants are not that closely related to each other either, but avian hybrids have been documented between species of quite unrelated lineages on a fairly regular basis.

 

 

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The Neighbors Have Noticed Clive

So when we had Clive out today he urinated a few times outdoors, including up against a tree trunk of one the silver maples in front of the house.

I made dinner this evening, and we had a boarding client who was coming to pick up her dog. Jenna took the client dog out for one last good walk about an hour after the sun set.

She came running back in the house telling me that she could smell red fox urine very strongly, and after careful examination, we noticed red fox tracks coming from across the road into our front lawn.

Clive is never taken near the road. He attracts too much unwanted attention, and our local conservation officer doesn’t like getting calls about a fox he knows is perfectly permitted and licensed.  Plus, Clive could get spooked and pull his leash loose, and he would probably run into the road and be hit by a car.

So what happened was that a dog fox in the neighborhood caught wind of Clive’s markings around the silver maples.  Last summer, I smelled where a red fox had urinated on one of these trees, as did every single one of our dogs, so I knew they were in the area. But now that we have a tame young male fox, the local breeding male fox is less than impressed with the young upstart leaving those markings on turf.

Clive is attracting the attention of the neighbors. My guess is we’re going to see lots more of their sign and maybe catch a glimpse of them as the late winter red fox mating season winds up.

I doubt that any of the local reds are cross foxes. All the ones I’ve seen in Ohio, West Virginia, and Pennsylvania have been the normal phase reds. But the foxes don’t know what color they are. They just operate by their nose and their base instincts.

Clive can never go wild. He’s from a long line of fur farmed foxes, and if he were to be released, he’s so friendly with people that he’d probably be suspected of being rabid and killed on sight.

So here is another aspect of owning a tame fox. The local red foxes don’t really care that much for the tame ones, and virtually everyone in the continental US lives near red foxes. If you bring a tame one into your home, you will be upsetting the locals, and I don’t just mean your human neighbors either.

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Playful Clive

We had Clive out today for a bit of fun. These photos should give you an idea of what his general temperament is. He is a total clown.

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Whippets on the run

Zoom (cream and white) and Poet (brindle and white) having some fun this morning

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Bobcats and Canada lynx hybridize– but not much

North America has two species of lynx, the widespread bobcat (Lynx rufus) and the boreal-adapted Canada lynx (Lynx canadensis). The two species do have some range overlap across the northern-tier of states, and when Canada lynx ranged down the Appalachians, their range overlapped much more extensively.

These two animals behave quite differently from each other. The bobcat is a generalist predator that hunts everything from mice and voles up to white-tailed deer, while the Canada lynx specializes in hunting snowshoe hares.

The bobcat is found in Mexico and throughout the southeast, especially in Florida.  Those southernmost bobcats are often not much larger than domestic cats, but the biggest bobcats, which are found in the Great Lakes states, are actually larger than Canada lynx.

It is well-known that bobcats and Canada lynx do hybridize. Hybrids have been produced in captivity, and hybrids have been encountered in Maine, New Brunswick, and Minnesota.  These hybrids are apparently fully fertile, which leads to the question of how much the two species really do hybridize.

A group of researchers looked into a big sample of bobcats and Canada lynx that came from across the continent. Of the 2,851 cats sampled, only 7 had any evidence of introgression from one species to the other.

This finding shows that bobcats and Canada lynx do hybridize, but it is virtually unknown in the wild. The authors caution that if Canada lynx numbers ever become low, bobcat introgression could swamp the genetics of that population, effectively making the species disappear through hybridization.

This finding is quite different from what has been discovered with gray wolves and coyotes. Gray wolves and coyotes have apparently exchanged genes across North America, and animals of mixed coyote and gray wolf genetics are pretty common.

Because we don’t have evidence of a hybrid swarm, which we do with wolves and coyotes, we have very good evidence to consider bobcats and Canada lynx quite distinct species.  And conversely, it is within reason to question the validity of coyotes and gray wolves as being distinct species

I would love to see a similar study to the genome comparisons performed on gray wolves, coyotes, and admixed canid populations in North america performed on Canada lynx and bobcats. My guess is that there will be some evidence of very limited hybridization between the two species, but it will not be like coyotes and gray wolves.

We don’t have a good handle on when bobcats and Canada lynx last shared a common ancestor. We need some more genomic data to make this claim, but what we know now is that Canada lynx and modern Eurasian and Iberian lynx are sister taxa.

The bobcat is thought to be more basal to the lineage.  Lynx species have been roaming North America since the Pliocene. Indeed, the earliest lynx fossils were found in North America, not Africa, as we previously believed.

The bobcat evolved in North America. It is the last survivor of the endemic North American lynx that gave rise to the other species in Eurasia, while the Canada lynx came back from that ancestral Eurasian lynx population some 200,000 years ago. 

These animals have likely been distinct from each other for a very long time, but they have not yet lost chemical interfertility. It will likely be a while before this happens, but if climate change continues to threat Canada lynx populations, the bobcat will move north into their range and hybridization could become a threat.

So stay tuned to see what happens, but the genetic data clearly show that bobcats and Canada lynx are two distinct species that do rarely hybridize.

 

 

 

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Snowy face fox

Clive likes the snow!

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Snow whippet

Poet must be the world’s most cold tolerant whippet. He just wants his ball to be thrown over and over

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The sweet nebulousness of defining a species

Recently, I’ve been using this space to play around with the fuzziness of “species.” Hundreds of species concepts exist, and because different researchers have somewhat different perspectives, you will sometimes get real conflicts about whether something is a species or a mere subspecies.

In canids, we get caught up in species discussions that are about what really amounts to very little genetic variation. For example, red wolves, Eastern wolves, gray wolves, dogs, dingoes and coyotes are all lineages that have only radiated in the past 50,000 or so years.

By contrast Old World and North American red foxes, including the ones allegedly derived by those set out by English colonists in the seventeenth and eighteenth, last shared a common ancestor 400,000 years ago.  This finding means that we probably should regard the red fox of North America as Vulpes fulva.

But 400,000 years of divergence is nothing compared to the 3 million years estimated for the Indo-Pacifica and Atlantic-Mediterranean populations of loggerhead sea turtle. There has been some gene flow between the populations. Matrilines have flipped around South Africa, once 250,000 years ago and an once 12,000 years ago.

So researchers who specialize in wolf-like canids are debating over very small genetic differences and relatively recent divergence times.  Red fox researchers are only just now realizing that there are likely two species in what was once thought to be a Holarctic species. And those specializing in loggerhead sea turtles don’t really care that their species has such a deep genetic difference.  The occasional gene flows between populations are enough for them to recognize only one species of loggerhead sea turtle.

This problem gets more interesting when we start talking about “living fossil species.” Take this article on Futurity.org, which is entitled “Evolution Hasn’t Revamped Alligators in 8 Million Years.” This article discusses the findings of some paleontologists at the University of Florida, who have found 8-million-year-old alligator fossils in North America, and they are remarkably similar to the ones we have today.

One of the researchers is quoted in the article says,”We were surprised to find fossil alligators from this deep in time that actually belong to the living species, rather than an extinct one.”

I would be just a hair more careful in my language. Although one can certainly see that these ancient alligators looked and probably behaved very much like the current species, 8 million years is a long time. I doubt that current alligators and those from that time could even interbreed if they encountered each other today. From a biological species perspective, it makes little sense to call them the same species, but from a paleontological perspective, it makes more sense, simply because paleontology is more interested in morphology and ecology over the entire time a population has existed.

So yes, “species” is a nebulous concept, and that is a good thing.  It makes some legal aspects with conservation difficult, because we have an Endangered Species Act that is about a hard and fast definition of a taxonomic entity.  In reality, the whole nebulous side makes for interesting levels of inquiry. If the Neo-Darwinian synthesis correctly describes the origin of biodiversity, then we would expect these discussions and debates to be commonplace.

They certainly are quite common in taxonomy and systematics. They probably always will be. Part of what defines a species are the biases of the classifier, which can often be contradictory.

For example, I have no problem with the new taxonomy of wildcats that posits the European wildcat into a different species than the Near Eastern/North African species. However, I disagree with the position of the domestic cat, which derives fro the Near Eastern/North African species, as its own unique species.

That bias may come from the simple fact that I am more familiar with domestic dog taxonomy, and I have come to accept that domestic dogs are best classified as a divergent form of gray wolf. If the domestic cat derived from its wild ancestor much more recently than the dog derived from its wild ancestor, why would it make any sense to classify the domestic cat as its own species?

So in zoology, we have all these different perspectives on how to classify species. Specialists in sea turtles are able to tolerate a genetically quite divergent species, while experts in wolf-like canids will debate over much more recently divergent lineages. These researchers really don’t talk to each about their ideas.  Indeed, the only time loggerhead sea turtle researchers worry about what specialists on the wolf-like canid side are doing is when they need to figure out how to stop coyotes from destroying the turtles’ nests. But they don’t need to know the complexity of the systematics to find an answer.

However, it is amazing how different specialists come to tolerate variation within one species. That nebulous nature of the various species concepts makes for some interesting variations on what specialists accept as normal.

Specialists often have very different ideas in mind, depending upon what they are used to, and I find it beautiful, even if it a bit confusing at times.

 

 

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