The hearty ingredients of Canis soup

[Reposted from my post on Scientific American’s guest blog.]

The wolf is iconic and charismatic. We see him on t-shirts, on posters, and in fantasy novels. Conservationists do battle with ranchers to preserve populations of wolves. The coyote, on the other hand, is neither iconic nor loved. A newcomer to suburbia, he is feared as a suspected predator of cats, small dogs, and even small children. He is rarely seen on t-shirts; his name is not used to designate a rank of Boy Scout.

But now that we have the genetic tools to look at these animals’ genomes, it turns out that many of the populations of coyotes in North America are actually coyote-wolf hybrids, as are many of the populations of wolves. Unable to draw clear lines between these species, biologists have dubbed the populations of hybrids “Canis soup.”


What’s a Canis?

The term “canid soup” has also been used for this mess of wolf, coyote, and even dog genes that we find in some populations of canids. So what does Canis mean, and what is a canid?

These are terms related to the scientific classification of the species in question. Going through the hierarchy, we have Kingdom Animalia, Phylum Chordata, Class Mammalia, Order Carnivora, Family Canidae (canids), and Genus Canis. Wolves, dogs, jackals, and foxes belong to the family Canidae, but only wolves, dogs, and jackals (not foxes) belong to the genus Canis. We call the wolf-like canids “canines” and the fox-like canids “vulpines.”

As foxes do not interbreed with wolves, dogs, or jackals, what we’re talking about here is correctly Canis soup, or perhaps canine soup, but not canid soup.

Is it Canis or is it soup?

The more you dig into wild canines in North America, the more unclear it is where any species lines should be drawn. So who makes up our cast of characters?

Gray wolf (Image courtesy of Wikipedia) The first ingredient in Canis soup is the charismatic North American gray wolf or timber wolf, Canis lupus, sometimes known as Canis lupus lupus to differentiate him from the dog and the dingo, who belong to subspecies. The gray wolf is the largest wild canine, at a 79 pound (36 kg) average weight. (Domestic dogs of some breeds, of course, weigh more than that.) His coat coloring can vary from white through blond, brown, grey, and black. He is found in the western parts of North America.

Western coyote (Image courtesy of Wikipedia) Next is the Western coyote, Canis latrans. This animal is also known as the American jackal or prairie wolf, suggesting that there has been some confusion about how to distinguish canine species for some time. The Western coyote is a significantly smaller animal than the gray wolf, weighing in closer to 20 pounds (7-14 kg). His coat color is less varied than the gray wolf’s, almost always a grey-brown as you see in the image here.

Eastern wolf (Image courtesy of Wikipedia) The range of the Eastern wolf or Algonquin wolf, Canis lycaon, is Ontario, Canada. This wolf is smaller than the gray wolf, and has a distinctive grey-red coat with black hairs along his back. We believe that this wolf was the original North American canine, and that Canis lupus and Canis latrans immigrated over the land bridge from Europe. There’s a lot of debate about the species status of C. lycaon, as many Eastern wolves appear to have significant C. latrans heritage. Some people suggest that the Eastern wolf is in fact a C. lupus/C. latrans hybrid, or, alternately, a subspecies of the gray wolf, C. lupus lycaon.

Eastern coyote/coywolf (Image linked from Eastern Coyote Research) The Eastern coyote, spreading along the east coast of the United States, is significantly larger than his Western counterpart. He turns out to be a coyote/wolf hybrid, and it has been argued that he should more accurately be called a coywolf. His wolf ancestors seem to be Canis lycaon —  but then again, there is debate about whether C. lycaon is really different from C. lupus at all.

Red wolf (image linked from True Wild Life) The red wolf or Southeastern wolf is subject to truly intense debate about species status. Is he his own species, Canis rufus? A subset of the gray wolf, Canis lupus rufus? Or a population of Eastern wolf, Canis lycaon? He has a beautiful red coat, and is smaller in size than the gray wolf. His range was historically the southeastern U.S., but he went extinct in the wild by 1980. A founder population of 19 animals survived in captivity, and a reintroduction project in North Carolina was begun in 1987. Here the red wolf is today enthusiastically interbreeding with coyotes, leaving conservationists to wonder what they are conserving.

The three species of wild canines in North America today, then, are Canis lupus, Canis latrans, and Canis lycaon. But we really have just two soup ingredients, wolf and coyote. There are pure wolves (Canis lupus) and there are pure coyotes (Canis latrans), and there are populations that are mixtures of more or less wolf and more or less coyote (Eastern wolves, Eastern coyotes, and red wolves). There appears to be some dog mixed in there, too. You can think of gray wolf and Western coyote as ingredients, and everything else as soup.


Coyote flavor versus wolf flavor

The 2011 paper “A genome-wide perspective on the evolutionary history of enigmatic wolf-like canids” analyzed the various soup flavors out there and presented their findings in some easy-to-understand charts (below). Here, the different colors represent different amounts of each ingredient. The first chart describes the Eastern wolf, here referred to as the Algonquin wolf, which is mostly gray wolf (green) and joint wolf/coyote (yellow), but also has significant coyote (red). The second chart describes the red wolf; at a glance, it is obvious that the red wolf has a much larger percentage of coyote genes (again, red in this chart). These charts both use τ to denote the number of generations since the most recent admixture with another species.

Two recipes for wolf flavored Canis soup
(vonHoldt, 2011)

The two coyote recipes pictured below describe two subpopulations of what I have described as the Eastern coyote; this particular paper considers them split into Northeastern and Southeastern coyotes. At a glance, these populations are mainly pure coyote (red), with big dashes of mixed coyote/wolf (yellow), and small but notable amounts of our friend the dog (dark blue, light blue, and pink).

Two recipes for coyote flavored Canis soup
(vonHoldt, 2011)

Wild canine populations challenge us to let go of our obsessive need to categorize. Instead of slotting a canine population into a single species category, we might instead think of it as existing on a spectrum from “wolf-like” to “coyote-like.” A strongly wolf-like canid would be larger, sixty to ninety pounds. He would require a larger range, and would be a deerivore, subsisting off of larger game. He is likely to be a shyer animal, found only in more rural or wild areas. Conversely, a strongly coyote-like canid would be much smaller, fifteen to thirty pounds, with a smaller range. He might eat deer as well as rabbits and et cetera (probably a lot of et cetera, as coyotes are more willing to scrounge than wolves are). He would be more likely to be found in suburban areas, with a greater tolerance for human proximity. A given population of canines might fall anywhere on the spectrum between the two. The fact that a spectrum actually exists is beautifully demonstrated by the Eastern coyote, who has mixed coyote/wolf ancestry, is mid-sized between coyote and wolf, and has a mid-sized range.

What’s your preferred flavor?

Does the intermixture of various ingredients in the formation of soupy populations matter as more than a gee-whiz story? To some people, the answer is very much yes. The conservationists who are committing significant resources to the preservation of the red wolf don’t want to see the wolves that they reintroduce interbreed with coyotes. If the reintroduced wolf population blends into a coyote population, then are these resources actually being spent just to support a bunch of coyotes (who have been doing fine on their own)? At the same time, evidence shows that the founder population of 19 red wolves was already significantly coyotified, and we’re not sure how long it’s been since there have been any pure Canis rufus specimens in North America.

It is, of course, possible to think about the problem without asking for genetics to provide the complete answer for us. The red wolf is a red wolf, a beautiful, iconic animal that has lived in the southeastern United States throughout living memory. We know what the red wolf looks like (and that hasn’t been changing much, no matter what is happening to his genes). We also know that he is important in a particular environmental niche, and that hasn’t been changing much either.

Practically, the mixture of coyote genes into fragile wolf populations may be a good thing. Because coyotes are better at living on smaller ranges and in closer proximity to humans than wolves are, they are better adapted to the realities of North America today. As their genes mix into wolf populations, these populations become demonstrably more robust, more able to tolerate human presence, and able to survive on smaller ranges. It is possible, in fact, that coyote genes are exactly what are eventually going to allow a red wolf population to flourish without human assistance.


Conclusions, if we can make any

Does it matter that some of what we think of as wolves have coyote genes? I think the answer comes down to a cultural perception of the wolf as a romantic and charismatic creature, and of the coyote as a pest. Perhaps any mixture of the two is perceived as diminishing the wolf. A friend of mine once made this analogy: if you have an entire bottle of fine wine, and you pour just a teaspoon of sewage into it, now you have a bottle of sewage. Does any amount of coyote, no matter how miniscule, make the wolf impure, and less worth conserving than it was?

As a culture, I hope we can come to appreciate the strengths that the coyote brings to Canis soup, in his ability to coexist with humans in the modern world. He may be what saves populations of charismatic wolves from permanent loss. As we look at populations of canines in North America, we should learn to say that one is more coyote-like and another more wolf-like, on a spectrum from one flavor of soup to another, and appreciate the benefits of both.

Canis soup has been used before as an example of the blurriness of some species lines and the inadequacy of many existing definitions of a species, but it also provides some interesting insights into the fluidity of canid morphology and behavioral characteristics. How did something as large and wild as a wolf become something as variably-sized and tame as a dog? Moreover, how did this change happen (presumably) without a carefully planned breeding program? Why is it so easy to breed types of dogs with such different behavioral and physical characteristics, especially compared to the much more limited variety of breeds of cat, horse, or cow? The canine genome clearly has the capacity for expression across a startlingly wide array of phenotypes. The evidence of this variety has always been right before our eyes, but we are just beginning to understand its implications.

References

Adams, J., Leonard, J., & Waits, L. (2003). Widespread occurrence of a domestic dog mitochondrial DNA haplotype in southeastern US coyotes Molecular Ecology, 12 (2), 541-546 DOI: 10.1046/j.1365-294X.2003.01708.x

Adams, J., Kelly, B., & Waits, L. (2003). Using faecal DNA sampling and GIS to monitor hybridization between red wolves (Canis rufus) and coyotes (Canis latrans) Molecular Ecology, 12 (8), 2175-2186 DOI: 10.1046/j.1365-294X.2003.01895.x

Hailer, F., & Leonard, J. (2008). Hybridization among Three Native North American Canis Species in a Region of Natural Sympatry PLoS ONE, 3 (10) DOI: 10.1371/journal.pone.0003333

vonHoldt, B., Pollinger, J., Earl, D., Knowles, J., Boyko, A., Parker, H., Geffen, E., Pilot, M., Jedrzejewski, W., Jedrzejewska, B., Sidorovich, V., Greco, C., Randi, E., Musiani, M., Kays, R., Bustamante, C., Ostrander, E., Novembre, J., & Wayne, R. (2011). A genome-wide perspective on the evolutionary history of enigmatic wolf-like canids Genome Research, 21 (8), 1294-1305 DOI: 10.1101/gr.116301.110

Way, J., Rutledge, L., Wheeldon, T., & White, B. (2010). Genetic Characterization of Eastern “Coyotes” in Eastern Massachusetts Northeastern Naturalist, 17 (2), 189-204 DOI: 10.1656/045.017.0202

Wilson, P., Grewal, S., Mallory, F., & White, B. (2009). Genetic Characterization of Hybrid Wolves across Ontario Journal of Heredity, 100 (Supplement 1) DOI: 10.1093/jhered/esp034

Zimmer C (2008). What is a species? Scientific American, 298 (6), 72-9 PMID: 18642545

Book review: Control unleashed

I recently finished Control Unleashed: Creating a focused and confident dog, by Leslie McDevitt. This book is designed for people training dogs in agility who are having issues with their dogs’ ability to focus, so you might imagine that the book isn’t useful to people with fearful dogs like mine. But it turns out, unsurprisingly, that if your dog is having issues focusing, he may well actually be nervous about something in his environment, such as strange people or other dogs. This book is full of exercises for helping your dog be more comfortable and relaxed, whatever his reason for being distractable. It was incredibly helpful to me in thinking through exercises for my shy dog Jenny, to help her learn to trust the world a little more. Even if you don’t do agility with your dog, this book may be helpful in making you a better trainer. It includes many examples of specific training exercises to try, and stories about situations in which they were particularly helpful. It was also an enjoyable enough read that I got through it while working long hours on some difficult rotations — I looked forward to finding ten minutes to read it before bed. I recommend this book to everyone who has has basic understanding of positive training and learning theory, and wants to learn more.

I have become a chef. For owls

Some days it seems like none of your patients will eat. I asked the intern at the wildlife clinic where I was doing a two week rotation what his advice was for convincing the tiny screech owl (214 grams of cute) to actually ingest food on her own. We had tube fed her; this worked, but you don’t really want to have to do it every day, and she really doesn’t want you to do it every day. We had force-fed her mouse bits with tongs, which was even worse. The intern suggested peeling the skin off of baby mice “so she can see the meat.“


Awesome.

In vet school, you get a little inured to gross things. I cut up mice for raptors every day on this rotation without getting squeamish. But I found peeling the skin off of two day old mice (thankfully already dead) to be a bit much. The intern was a little bewildered by my reaction. Anyways, it didn’t work.

The next day I went to a different vet for advice. “Sometimes,” she said, “they like to have the mice split open and the liver displayed... You can leave the skin on.” I did this. I was artistic about it. HERE ARE THE LIVERS. PLEASE EAT THEM.

And that night, she ate.

My next problem patients were two barred owls who had recently been transported a fairly long distance, which we were examining before they were placed into permanent captivity, as they were not releasable. These guys really didn't want to eat. I laid the mice out enticingly next to a branch on the ground. I split them open and DISPLAYED THE LIVERS. No.

The intern said, “They don’t want to come off their perch. They’re scared. Put the mice on the perch.” Easier said than done (he said it, I did it). One of the owls inevitably reacted to my entry into the pen with OH HOLY CRAP I AM GOING TO DIE, flying back and forth at high speeds. It wasn’t a very big pen. I covered my head with my arms and crept at a snail’s pace towards the perch. Veeeeery slowly I balanced the mice on the perch. And crept away again. That night, the owls ate.

The next day, as I was artistically displaying peeled mouse haunch for an Eastern box turtle (the mealworms weren’t working as they would just escape into his cage and set up shop there) I thought to myself: how did this become my life?

Dogs and babies

Today I heard this sad story third-hand: as a baby is crawling away from Grandma’s dog, who has always been fine with him before, the dog without any warning pounces on the baby and bites him. The baby loses part of an ear and has deep wounds on his face. The dog is euthanized. The parents were there to supervise, but it all happened too fast to prevent. What went wrong?

The first thing I want to say is that at the point that a dog bites a child (or any human) this badly, I agree that the dog must be euthanized. He is not safe. For this reason, it’s really important to figure out how to keep this situation from happening in the first place, for the sake of the baby and the dog.

What was going on in that dog’s head? We can’t know for sure, but it sounds to me as though the dog was treating the baby like prey. He pounced when the baby was moving away from him, and he bit to injure. If he had been trying to play with the baby, he might have bitten hard enough to bruise, but dogs have excellent control of their teeth, and a bite bad enough to remove part of an ear was probably intentional. The fact that the baby was moving away from him at the time is supportive evidence — the sight of something small and helpless, which makes high-pitched noises and moves erratically, running away from him may have triggered him to act.

Do dogs really act like predators around babies, even if they know them? Some dogs, not all. I would be particularly suspicious of dogs with high prey drives — dogs who are obsessive about chasing small animals outside. They may learn to like small animals who are part of the family, like cats, but with dogs like this, I would be very careful with my introductions. In the case of a human infant, I wouldn’t leave the baby on the floor with the dog loose in the same room unless I really, really trusted the dog. I live with four good dogs who get along just fine with cats, but there is only one of them that I would trust with a baby on the floor. The price is just too high if you make a mistake.

How can you prevent such a situation, since the dog gave no warning signs? I was not there, but I can almost guarantee you that the dog did give warning signs; his owner was just not trained to read and understand them. The dog probably did subtle things like stare at the baby a little too long or sniff it a little too aggressively — things that wouldn’t make the average dog owner think twice, but would make the average dog trainer extra cautious.

So what do you do if you’re expecting a baby and you have a dog? Or if you are a grandmother and want your grandchild and your dog to get along? The safest and easiest answer is to not let the dog and child interact until you know you can trust them together. Put them together for short periods of time only, while you are holding the child, and observe the dog closely. Don’t leave them on the floor together until you are confident that the dog will ignore the child and that the dog shows no stress, fear, or predatory behaviors around the child. If you don’t think you can read the dog well enough to tell, hire a dog trainer to evaluate your dog. A dog trainer can help guess what problems your dog might have around a child, tell you specific signs to look for, be a resource to ask questions, give you tips on how to manage them together. To find a certified dog trainer in your area, search on the Association of Pet Dog Trainers site.

Dogs and kids can get along great, if they are introduced carefully, and when the kid is old enough. But the consequences of a bad relationship between the two are so serious that it is very important to take those introductions seriously, and to make sure you’re seeing things from your dog’s point of view before you assume everything’s okay.

The cat in the tree

The skinny little tree was only about 30 feet tall and growing in the middle of a swamp. Recent flooding had surrounded it with water several feet deep. And yet somehow an orange cat had managed to climb it. He was perched precariously: when I first saw him, he was jammed into the fork of two branches, and his every movement made the little tree bend. I was riding with an animal rescue service, and we had been called out to get the cat out of the tree. It was supposed to be a simple job of using climbing gear to get up the tree; the rescue driver was trained to do jobs like this. But this tree was never going to bear her weight. It could barely hold the cat. Even getting to the tree was going to involve wading through waist-deep water in the chilly November weather.

The cat was glad to see us. He made eye contact and meowed, clearly asking for help. But it was not immediately clear how to help him. We talked about our options, and eventually decided that we were going to have to call back to the shelter for assistance. The rescue driver called her boss, but initially failed to convince him that she couldn’t just climb the tree. She eventually had to photograph the situation on her phone and send him that as proof that the tree couldn’t support a ladder, and that trying would just knock the cat off so that he would fall 30 feet into the cold water.

As we watched and talked about what to do, took photos and made phone calls, the cat eventually stopped talking to us. I think he gave up on us. A few minutes later, he decided to change positions. I think his legs were getting tired of holding him up. After all, we had no idea how long he had been up there; a good samaritan had phoned about him about an hour previously, but the road we were standing on was small and rarely used, so he could have been there unnoticed for hours. I also think he was trying to assess his situation, see if he could take matters into his own hands and find his own way down, since we were clearly useless.

As he moved around on the little tree, it bent terrifyingly. Unable to help ourselves, the rescue driver and I yelled “No, stay still!” up at the cat. This had about as much effect as you’d expect. But he managed not to fall. Over the next thirty minutes, waiting for help to arrive, we watched as he periodically moved around and tried to find a way down. We became worried enough about him that the driver put on her dry-suit and made her way down to the water so that she could fish him out if he fell.

Finally, as the light was failing, our help arrived, in the form of the driver’s boss who had driven down from Boston. Now things started to move quickly. As the cat watched with trepidation, the driver got into the water (in her dry-suit) with a big net; I hovered with another big net; and the driver’s boss attached ropes to the little tree. He pulled, and the tree bent towards the roadway where we stood. The cat braced himself, then, when he was only about ten feet off the ground, jumped. I swung with the net and missed. We watched as the cat ran at top speed away from us down the long road and disappeared into the night.

Links post

I haven’t been reading many blogs lately, so these link recommendations are pretty old. Still delicious, though.
 

• Who’s your double merle daddy? (Border Wars): The devil’s bargain of breeding a collie who is guaranteed to produce blue merle colored puppies.
• Shelters: Pit bull drop-offs on rise (Telegram.com): My local newspaper reports that since Worcester, MA passed its anti-pit bull ordinance, pit bull drop-offs at the area shelter have increased.
• It works! How to stop an approaching dog in an emergency (The Other End of the Leash): Patricia McConnell’s excellent advice about what to do when a dog is running at you, and your dog isn’t going to react well. Comes with video, so it is extra yummy.
• Patricia McConnell Seminar: What Science Tells Us About Puppy Development (Reactive Champion): A summary of a Patricia McConnell seminar on, oh wait, you can read the title.
• Breeding Discontent (Paula Kislak, DVM on the HSVMA website): More on the pitfalls of irresponsible dog breeding practices. “All stakeholders [in dogs] ... should forge cooperative alliances and develop robust plans to improve canine health and welfare”

How to spay a cat fast

Yesterday I spent the day on a spay/neuter trailer. The shelter which owns the trailer sends it out to low-income areas to spay and neuter a large number of cats and dogs at low cost. Yesterday was a slow day; we spayed and neutered sixteen cats. Well, the vet spayed seven and neutered three; I spayed one and neutered three. Meanwhile, she explained high volume spay/neuter techniques to me.

The key to high volume spay/neuter is, obviously, speed. She can spay a cat in seven minutes. It takes me about thirty; a general practitioner who has more experience than I do, but isn’t as obsessed with speed, might take ten or twelve. This is what I learned:

• Keep your surgical field (the animal!) clear. Take the time to replace your instruments on your instrument tray when you are not using them, so that you have less visual clutter.
• Always know where each surgical instrument belongs. Don’t leave them in a pile or even a random row on your tray. Have an order for them — any order, so long as you are familiar with it and can reach for a particular instrument and know right where it will be.
•  Don’t waste movements. If you’re reaching to the right to grab a new instrument, don’t twist all the way over to face the tray; just reach your right hand over.
• Don’t get tangled up in your instruments. Be willing to take a second to switch hands if you have yourself in an awkward position.
• As you’re working on one step, have your next step in your mind. What instrument will you be reaching for next?
• Relax. Stand up straight. Breathe, breathe, breathe.