So, what is Fur Anyway?

Pet owners are usually well aware of how abundant fur can be

Human hair

The short version is that fur is a subset of hair, but that's a bit of a major oversimplification. To begin, let's look at the anatomy of hair in general.

As we all know, hair is something that only mammals have. It serves some of the same purposes as scales and feathers, but is definitely unique. The main function of hair is insulation and thus temperature regulation, which is vital for endotherms to maintain homeostasis. Interestingly enough, scientists haven't been able to pinpoint when it evolved, including whether endothermy or hair were first on the scene.

Anatomy of a hair follicle

Hair is a complicated product of the outermost layer of the skin, known as the epidermis. The hair follicles form there, then grow downward into the lower dermis. A bulb forms, and this bulb is where the live cells are and where hair growth happens. The part you actually will see, the hair shaft, is comprised entirely of dead cells. The hair root is surrounded by nerves which are sensitive to touch. This is why a hair cut doesn't hurt but pulling hair out does. Hair shafts will also have muscles and these muscles make your hair stand on end, which in humans will result in what we call goose bumps. Sebaceous glands will also be associated with hair follicles and are the source of the oil that can be so often found on and around hair.

Hair structure

Hair structure is also fairly complex. The innermost portion is call the medulla and the density of cells can vary a lot here. There is usually a lot of empty space, but in some species cells are entirely lacking, making the hair hollow. Most of the hair shaft is the cortex, which is made up of very densely packed cells. Lastly, there is a transparent layer known as the cuticle. This part is scaly in appearance and the scale pattern can vary quite a bit, to the point that examining hair is not a bad method for identifying a species. This is particularly true of species that may otherwise look very similar and prove difficult to identify using other characteristics.

Now, let's move on to types of hair. There are more than you might have originally thought. There are two basic types of hair with more specific types fitting into one of the two. Angora hair is hair that never stops growing and which may or may not shed. This would be what humans have on their heads, what horses have in their mane, and what certain breeds of dog have all over their bodies. In contrast, there's definitive hair, which will only grow so long and which shed and re-grow regularly. This would be what's on the body of a cat and most dogs. Within angora and definitive hair, there are a number of other relevant hair categories, and this is where it starts to get complicated.

Vibrissae on rats, along with pelage

Within the definitive hair type, you see vibrissae and pelage. Vibrissae are stiff and used for sensory purposes, with the best known type being whiskers. Pelage is what most people would describe as fur and which consists of guard hairs and underfur. Within this, there are a few different types of guard hair. Awns are the most common type, but spines, as in what you find on hedgehogs and porcupines, are also a kind of guard hair. As for angora hair, bristles are an important type, being used for visual display as in horses and lions. Wool and velli are also specialized types of hair. Wool is long and soft. Velli is the "downy" hair that you see on newborn animals.

Horses have numerous types of hair: vibrissae, pelage (both guard hair and undefur), and bristles

As a final note, in this blog I have used the terms fur and hair before in perhaps an unusual way. In general, I refer to angora hair as hair and definitive hair as fur. Though this is a gross oversimplification, it's at least a simple shorthand that breaks the two into appropriately separate categories and can be useful when talking about such things as dog coats. It's easier to explain to someone that a Shih Tzu has hair like humans have on their head rather than saying it's angora hair and thus exhibits a continuous growth pattern.

Source is Mammalogy: Adaptation, Diversity, Ecology. Images are from Wikimedia Commons and are under Creative Commons licenses or are copyright free: one, two, three, four, five, six.

How to Calculate your Dog's Cephalic Index

Dogs have heads that vary a lot in size and shape

For those who don't know what the cephalic index is, please refer to my first post on the subject. As I mentioned there, the index is a comparison of the length and width of a skull. To calculate what index, you must first get some measurements. The two measurements you will need need to be taken from the absolute broadest part of the skull for the width and the absolute longest part of the skull for the length. To find these, it's easiest to look for bony protrusions.

For the skull width, gently feel between the dog's eye and ear. You should find a bar-shaped bone: the zygomatic arch. This projects out from the skull over the jaw muscles on either side of the head. Since dogs have rather strong jaw muscles, this will always be the widest part of the skull. If you're curious, check it out. Feeling under the ears will reveal a smaller skull width than what is seen at the zygomatic arch. To measure the skull width, don't simply lay a tape measure from zygoma to zygoma. Since the skull isn't flat, this will give you a falsely large measurement. This is why calipers are usually used to make these measurements. You can jerry-rig a set of calipers using two straight objects and a ruler, but this is difficult and there are easier ways to do it, which I will discuss later.

For the skull length, find the body protrusion on the back of the skull: the occiput. It should be fairly simple to find, sitting between the ears and often very close to where the head meets the neck. The prominence of this can vary a lot by breed, so if you have a dog with a very round skull you may not be able to find it. If this is the case, take the measurement from the farthest protruding part of the skull you can find. Measure from this point to the tip of the nose.

What would be the easiest way to get these measurements? Well, a lot of dogs would probably not be very happy with you messing with their head, so an alternate method of finding these measurements is using pictures. If you take a photograph of your dog's head from above, you can use this to measure the CI. Units don't matter, so you can use one measurement to figure out the other. Here's me doing this with Ebon:

Width is one unit and length is two and eight-one hundredths units. So, after calculating the CI ((1 x 100)/2.08), I found out that Ebon has a cephalic index of just slightly over forty-eight. This is really rather small, definitely less than seventy-five, and makes him dolichocephalic (for those that are curious, my dad's greyhound, Siggy, has a CI of 44.6). Now, I'll calculate the index for a bulldog:

The length is one unit and the width is one and fifty-five-hundredths. After calculating the CI ((1.55 x 100)/1), I found that this bulldog has a cephalic index of one hundred fifty-five. This is rather ridiculously large since the scale usually only goes to one hundred, and may be off as the dog's head is somewhat tilted. Either way, this dog is most definitely hyperbrachycephalic as his CI is far over eighty-five.

So, can you calculate your dog(s)' cephalic index? If you do, let me know what you come up with.

The First and third images are from Wikimedia Commons. The first is under a Creative Commons license and the third is copyright free. The second image is mine.

The Cephalic Index

Skulls that are brachycephalic and dolichocephalic, respectively

The cephalic index, also known as the cranial index, is the source of a series of terms that are really rather commonly used in such things as the world of dog fancy. However, it's likely that a lot of people out there don't actually know that the terms mean. It is a way of looking at the anatomy of the skull. The cephalic index is basically a percentage calculated by comparing the length of the skull to the skull's width. Specifically, it's the width multiplied by one hundred and divided by the length. If the index is seventy-five to eighty, the skull is oval in shape, also known as mesaticephalic or mesocephalic. If the index is less than seventy-five, the skull is long and narrow, also known as dolichocephalic. If the index is more than eighty, the skull is short and broad, also known as brachycephalic. If the index is more than eighty-five, the skull is even shorter and broader and can be called extremely brachycephalic or hyperbrachycephalic. In the past, and indeed currently, these designations have been used to describe different racial designations, which usually share very similar characteristics. Some populations have very long skulls, and thus tend to be dolichocephalic. Others have broad skulls and trend toward brachycephalic. Others are mesaticephalic, and still others are hyperbrachycephalic.

Dolichocephalic, index 64

Mesaticephalic, index 79

Hyperbrachycephalic, index 94

Of course, when looking at humans and the cephalic index designations there is one major characteristic that is lacking and is very important when applying the same terminology to dogs or other domestic animals: muzzle. Humans don't have a muzzle, so the cephalic index is almost entirely based on the shape of the brain case. This is far from true when looking at dogs, since dogs have muzzles. As such, the muzzle plays a major role in determining a dog's cephalic index. Generally, dogs with long muzzles will be dolichocephalic, and dogs with short muzzles will be brachycephalic. However, this is not always the case. For example, there are dogs with fairly moderate muzzles that would be classified as brachycephalic because they have very broad skulls.

Technically brachycephalic

In a series of posts to come, I will be discussing more about the cephalic index in dogs and why it can be so important.

Sources are Scientific Electronic Library Online, Encyclopedia Britannica, Encyclo Online Encyclopedia, . Images are from Wikimedia Commons and are under Creative Commons licenses or are copyright free: one, two, three, four, five, .

Mismark Case Study: Cavalier King Charles Spaniel

According to the AKC, Cavaliers come in four allowable colors, three of which are seen here: Blenheim, tricolor, and ruby. Black and tan is not shown.

The Cavalier King Charles spaniel is a popular pet and is one of the largest of the breeds in the toy group. Though the breed comes in four colors, two are more commonly seen: Blenheim and tricolor. There are also several mismarks, some of which are due to breeding within the allowable breed colors:

• Incorrect white
• Too much white on the face of a Blenheim or tricolor
• Any white on a ruby or black and tan
• Ticking 
• On a Blenheim or tricolor
• Incorrect tan 
• Seen on tricolors and black and tans 
• Incomplete pigment 
• Of the nose or eye-rims on a Blenheim or tricolor
• Blue eyes 
• Usually only seen on a Blenheim or tricolor

White on a black and tan

When it comes to incorrect white, both of the forms I describe are really to be expected when breeding for the allowable colors within the breed. The piebald gene (sp), which results in Blenheim and tricolor dogs, is recessive to the solid gene (S) on the Spotting locus. However, in most cases a dog who is heterozygous for these genes (Ssp) and thus carrying piebald will have some amount of white. This is often as little as a bit of white on the chest and/or toes, but this may extend up the chest and even result in some white on the face and tail. The problem is: according to the standard, no amount of white is allowable on ruby or black and tan dogs. This means it is unlikely that the solid dogs are bred to the piebald dogs, leading to color class breeding. This is problematic, as it basically creates breed within breeds, narrowing overall genetic diversity to two smaller pools, and thus raising the potential for problems that result from increased homozygosity. Also, only breeding solid dogs to other solid dogs will not eliminate white markings. It's far from uncommon for a genetically solid dog to end up with some white on their chest and/or toes. This is thanks to normal developmental variation in the womb.

Too much white, lacking pigment

In addition to the above, "incorrect" facial white on piebald dogs is also far from uncommon. Facial white is controlled by as-of-yet unknown modifiers. Selection can favor one form of facial white, but it's almost impossible to eliminate the ones that would be considered "undesirable." Since this is true, dogs with more or less than the preferred amount of white shouldn't be surprises. Also, since selection in Cavaliers favors dogs with rather a lot of facial white, this likely increases the likelihood of a dog being produced that has too much white. In relation to this, dogs with a lot of white on the face are far more likely to lack pigment of the nose or eye-rims, or to have one or more blue eyes. Since the standard favors dogs with so much white on the face, this makes it quite likely that these dogs will appear.

Heavy ticking, too much white

As for ticking, there is a bit of a conundrum in the breed. Some ticking is fine, and a lozenge between the ears, which may or may not be a large ticking spot, is preferred. But, if a dog has too many ticking spots, it's not allowed. So, it's likely that the dogs that are allowed are heterozygous for the ticking gene (Tt) and the dogs that would have too many spots are homozygous (TT). So, why allow ticking at all if you're only going to penalize dogs that have too many spots?

Incorrect tan on the face

Another mismark that is based on normal color variation in incorrect tan markings. Taking the standard as it is stated, any tan on the outside of the ears is not to be allowed and any tan between the marking above the eyes and on the cheeks would also be incorrect. However, these things are not uncommon in tan pointed dogs. This is another case of minor differences being enough to make a dog "undesirable."

All of the mismarks that are seen in the Cavalier King Charles spaniel are really rather minor things that are to be expected from normal canine color inheritance. As such, they are nothing more than silly aesthetic preferences and do not reflect on the quality of the dog. Since this breed is a very common pet and, indeed, bred to be a companion, temperament and health should be far more important than what the dog looks like. Looks should never take precedence over these other, far more important traits. As such, color standards are really rather silly things based on nothing more than minor aesthetic preferences of the few people that wrote the standard. As the differences I have mentioned have absolutely no effect on the quality of a dog, eliminating a dog from the gene pool simply because it does not fit the color standard is ridiculous. Also, as purebreds are bred in closed registries, dropping any dog from the pool of potential mates makes it quite possible, and indeed likely, that a negative loss of genetic diversity will result. Since the color standard has also lead to color class breeding in the Cavalier, this is even more problematic.

Images are from Wikimedia Commons and Flickr.com under Creative Commons licenses: one, two, three, four, five.

Mismark Case Study: Gordon Setter

A Gordon setter in the breed's only acceptable color.

The Gordon setter is one of a small number of setter breeds, which also includes the English setter, Irish setter, and Irish red and white setter. Though the Gordon setter now only comes in one acceptable color, the breed's history included a number of other colors that are now considered to be mismarks. Part of why these colors are in the breed is due to its relationship with the other setters. So, what are these mismarks?

• Incorrect tan markings
• Dogs with more or less than than required in the standard
• Liver
• Inherited on the Brown locus, a dog must be bb to be liver
• Red
• Inherited on the Extension locus, a dog must be ee to be recessive red
• Too much white
• Inherited on the Spotting locus, a dog with a variety of genotypes can have too much white

Too much white

Looking at these mismarks, they are all recessively inherited except in dogs that are genetically solid but have too much residual white. All of theses colors were well known when the breed was young. Much like the Irish setter, the predominant color in the early years of the breed is actually not what you think it would be when looking at modern dogs. Gordons were once mostly tricolor with some dogs being solid black and tan, liver, or red, but the white markings and other colors fell out of favor and led to the production of the breed you see today.

This dog appears to be liver

The current breed standard for the Gordon only allows for black and tan dogs with specific tan markings. Dogs that are anything other than black and tan are disqualified and anything more than a small bit of white on the chest is not allowed. A dog with more or less than the required tan would be penalized, despite the fact that ten markings can vary greatly on dogs that are all genetically atat tan pointed. So far, it is known that there are modifiers that control this amount of tan, but it isn't known where they are or how they are inherited.

Too much tan

This is a case where color standard is based on, basically, fashion. What once was popular was no longer liked by those who wrote the breed standard, and thus those other colors faded into obscurity. However, since the colors are basically all recessively inherited, they continue to pop up on occasion in litters that are born today. These past decisions are really problematic when looking at the breed's history and what this holds for the future.

Too little tan

Since Gordon setters were originally hunting dogs, the main thing that they should be bred for is working ability. This was at least true of setters past. However, modern Gordons have a lot more emphasis placed on type and show potential. It remains true that Gordons were developed as working dogs and color has no affect on working ability. It also has no affect on health or temperament, which are both important to people who wish to have a happy life living with a dog, particularly if the dog is meant to be a pet. If breeders wish to emphasize the Gordon setter's place as a working breed and its ability to do field work, why should they place any emphasis on color?

Another major concern in the Gordon setter and any other breed is a loss of genetic diversity due to selective breeding. Since Gordons of only one color were favored, a lot of diversity was lost rather early on in the breed. Continued shunning of off-color dogs only drops more potential sources of genetic diversity from the breed and risks loss of some very good, sound individuals based on a silly cosmetic preference.

Sources are the American Kennel Club, Gordon Setter Club of New South Wales, and Gambit Gordon Setters. Images are from Wikimedia Commons or Flickr.com under Creative Commons licenses: one, two, three, four, five.

Mismark Case Study: Boston Terrier

Boston terriers come in three acceptable colors: black, brindle, and seal, all with white.

This dog would have too little white

The Boston terrier is a breed that came from crossing a number of different breeds together. In its ancestry are such breeds as the French bulldog and bull and terriers types, crosses between bulldogs and terriers that are the ancestors of such modern breeds as the bull terrier and pit bull. The reason why modern Bostons are so small is that they have since been bred down in size from the original stock. This ancestry also explains all of the colors that pop up on occasion in the breed. What are these mismarks?

• Too little white
• Lacking the required white chest, muzzle and blaze between its eyes
• Too much white
• Excessive facial white or "splash white"
• Any base color other than black, brindle, or seal 
• Liver, blue, lilac, fawn, gold, or tan point
• Not enough skin pigment
• The nose must be completely black
• Blue eyes
• Even a touch of blue disqualifies

Too much white and a blue eye

To begin, let's look at variations in the amount of white on the dog. Facial white is forever a conundrum in the canine world. In every breed that had facial white, there is a great amount of variation. This variation is controlled by as-of-yet unknown modifiers and is likely polygenic and inherited mostly independent of the Spotting locus that controls body white. This is the issue with having a rather strict requirement for facial white: there is no real guarantee that your breed will always have the same exact amount. This is why in breeds like the Boston terrier, too much white on the face happens so often. Too little white also happens, but in the Boston this appears to be a more unusual occurrence.

A splash rescue

The "splash" white is completely different. Piebald and extreme white can both be sources of the splash pattern, and both are recessive alleles on the Spotting locus. Most Bostons express the Irish white phenotype, which can vary from the minimal markings required by the breed standard up to what's often called collared Irish, which has white extending all the way around the neck and prominent white on the legs. Irish white is dominant to both piebald and extreme white, and as such it's very possible for dogs who conform to the standard to carry these alleles. Though not always the case, it's possible that some of the heavily marked collared Irish dogs have as much white as they do thanks to the recessives they carry. Extreme white especially can cause a dog to have more white than it would otherwise have. Minimal piebald can also mimic collared Irish markings, and so it's possible the occasional minimal piebald may slip into the show ring.

As for the dogs with off-standard base colors, there are really quite a number of possibilities. Here's the full list of possible colors, what they're called in the breed and the genes that cause them. Wherever I say black, this is basically interchangeable with brindle and seal. All three colors are caused by the K-black locus, with brindle (kbr) being recessive to black (K) or seal (K, bad black, possibly recessive to regular black).

Masked fawn puppy

• Sable/fawn 
• Recessive to black on the K-black locus, allows the Agouti locus to show through: Ay- kk results in sable/fawn
• Dog may or may not have a black mask and may be liver, blue, or lilac instead of black
• Tricolor/tan points
• Also on the Agouti locus: atat kk results in tan point; may be liver, blue, or lilac instead of black

Liver pigment

• Non-black pigment that would otherwise be black
• Liver/brown, recessive to black on the Brown locus: bb results in liver pigment
• Blue/gray, recessive to black on the Dilution locus: dd results in blue pigment
• Lilac/champagne, combination of the blue and liver genes: bb dd results in lilac

Recessive red

• Gold/honey/cream/blonde
• Caused by recessive red on the Extension locus: ee results in recessive red/clear red
• This gene hides all black body pigment, so any of the above, including blue/liver/fawn, but skin and eyes can still be effected by the liver and blue genes

Liver pigment and too much white

The major thing to note about all of the above is that they're all recessive. Due to this fact, you won't know your dog is a carrier until it throws a mismark puppy. Even if you remove those mismark puppies from your breeding program, its siblings have a two-in-three chance of being carriers. Why is that? It comes down to basic genetics: mismark puppies can only show up in litters bred from carrier parents or those expressing the gene. If breeding from two carriers, the expected ratio in the puppies is 1:2:1. That is, about one-forth will be non-carriers, half of the litter will be carriers, and the last forth will express the recessive mismark. If you remove the mismarks, you're left with a ratio of 1:2, or one-third non-carriers, two-thirds carriers. This means there's a rather high chance of the gene persisting, particularly if a breeder then chooses to linebreed or do other forms of inbreeding. Inbreeding only increases the likelihood that the recessive mismark will appear. This is why so many breeds have persistent mismarks.

Two dogs, three blue eyes

The two mismarks that I haven't yet mentioned are blue eyes and noses lacking in pigment ("Dudley nose"). Both are disqualifications according to the standard, and both are natural consequences of breeding for dogs with lots of white. White around the nose makes it quite possible that a dog will end up with a pink spot on its nose, or even a completely pink nose. So, expecting all dogs to have a fully pigmented nose when you are breeding for prominent white markings is a bit silly. It's basically the same with blue eyes. Though they can be independently inherited, the more white a dog has, the more likely it is to have one or more blue eyes. If the white touches a corner of the eyes, this also increases the chances. This is why so many dogs with a lot of white on their face have one or more blue eyes. Since the Boston standard desires very prominent white, blue eyes shouldn't be a surprise.

Liver pigment

As with every dog, color should be the last thing a breeder should worry about. There are so many more important things that a breeder should be striving to produce, like dogs with even temperaments and ones that are healthy. By disallowing certain colors, especially ones that were perfectly acceptable at one point in the breed's history (like splash in Bostons), there's a very high likelihood that perfectly good, healthy dogs are being dropped from the breeding population for extremely superficial reasons. This does nothing but narrow the gene pool and damage the breed as a whole. However, this doesn't mean that one should purposefully breed for mismarks. On the contrary, breeding for recessive is always bad because it usually means inbreeding, and potentially very heavy inbreeding at that. Inbreeding in any form and by any name (such as linebreeding) is very bad as it narrows gene pools and makes it more likely that deleterious recessives pop up. This is why so many purebred dogs have inherited health problems. Color should not matter. Purebred dogs have enough problems.

Apparently, there are some people out there selling merle Bostons. This color has been introduced through mixing with another breed. Since merle has so many negatives, there is absolutely no good reason to out-cross to purposefully introduce merle into a breed. 

Images are from Wikimedia Commons or Flickr.com under Creative Commons licenses: one, two, three, five, six, seven, eight, nine, ten. Image four is copyright to Rescue Furdaddy on Flickr.com.

Bycatch

A shrimping boat photographed in 1970

Bycatch is a term that many people are probably not aware of. It's used to describe all of the things that are not being targeted by fisheries, but are caught anyway. Every form of fishing can produce bycatch, which may or may not be fatal to the unintended catch.

Bycatch caught off the coast of Florida

As you can imagine, bycatch is quite controversial, especially when creatures such as dolphins and turtles are unintentionally killed. Unlike sea life, if an air-breathing creature such as a turtle becomes tangled in a net, it can easily suffocate from being denied access to the surface. Water-breathers are far more likely to survive, but that doesn't mean that their lives will be spared. Crowding in the net could still cause oxygen deprivation. The hauling in of the net can also be quite traumatic, especially if sensitive areas such as the gills are damaged. Then, there is time spent away from the water while the desirable catch is sorted out from the bycatch. The vast majority of bycatch is then thrown back as it was not intended to be caught in the first place. Anytime during this process, the bycatch may be eaten by predators, who often take advantage of fishing operations and whatever they throw overboard.

However, this doesn't mean that fishing operations are necessarily bad. Regulations have greatly reduced overall bycatch and provided protection for a number of endangered or threatened species. Also, food that is caught via fisheries can be a significantly better option than farmed alternatives, depending on the species and methods being used. A good example of this is shrimp. Though some farmed shrimp is not so bad, other shrimp farms seriously damage their environment. The farms are more productive if the shrimp are raised in fresh water, so a large number of farms are set up in mangrove forests and flooded with fresh water. This fresh water contamination will easily kill species in the surrounding area since mangroves are naturally saltwater systems and the species living there are adapted to salt water. Fresh water completely messes with their chemistry, especially their ability to retain essential dissolved minerals. Depending on how and where the shrimp are caught, it's far less damaging to the environment to catch them in the wild.

A turtle escaping a net thanks to a TED

Bycatch is still a concern, though. When looking at net design, a mesh meant to catch a certain species will allow smaller species through, but will catch basically anything that is larger than the target species. This is what causes most bycatch. As I mentioned before, regulations require the use of devices that help reduce or eliminate bycatch numbers. Two very important devices that are used in trawling are Turtle Excluder Devices (TEDs) and Bycatch Reduction Devices (BRDs). Both have numerous different variations, but what they accomplish is always essentially the same. A TED is specifically meant to protect sea turtles by giving them a route to escape through before they become trapped in the net. It will also provide an escape point for any large animal. In the case of the one pictured, the bar size is what determines the size of the animal that is allowed past into the codend, or the part of the net where the catch gathers. BRDs are usually placed past the TED, closer the codend. BRDs are often little more than holes in the net that are meant to allow bycatch an escape route. However, fishers are often not fond of them as it can lead to loss of some of the target species. Another interesting aspect of both TEDs and BRDs is that at least one animal, dolphins, have begun exploiting the holes in the net. There has been footage taken of these intelligent mammals poking their heads into the net holes and catching passing fish.

I feel lucky to have observed first-hand some of the research that is being done to try and reduce bycatch, specifically in shrimping. Through the University of Georgia Marine Extension Service, I was part of a group to take a trip on the R/V Sea Dawg, a shrimp boat turned research vessel. Some of the research that is being done on the vessel is the use of a different sort of TED that could also act as a more effective BRD. Results were looking promising with very large reductions in bycatch, so hopefully the modified TED will help reduce what can sometimes be absurdly copious amounts of unintentionally caught species. This setup would also be favored by fishers as it reduces the modifications that have to be made to their nets.

The fact remains that certain fishing methods produce far more bycatch than others. Poll fishing is usually more species-specific and less traumatic for what unintended animals that are caught. Purse seining, in contrast, can produce terribly excessive amounts of bycatch. For those who want to be environmentally conscious about their seafood choices, many organizations provide information on which methods are most damaging and what species should be avoided altogether.

Sources are the Consortium for Wildlife Bycatch Reduction, National Oceanic and Atmospheric Administration, World Wildlife Fund Smartgear Competition, Monterey Bay Aquarium, and Sea Grant Rhode Island. Images are from Wikipedia or Wikimedia Commons and are copyright free: one, two, three.

Are Orcas Whales?

Wild orcas (Orcinus orca) off the coast of Alaska

One discussion I have seen and heard numerous times both on the internet and in my discussions with people in person is about the placement of the orca. Is it a whale or isn't it? Since the species is perhaps more commonly referred to as the killer whale, the question of whether the species is truly a whale can be quite confusing. This is especially true of those who do not have a very good understanding of what whales are or what an orca is.

Baleen of a feeding humpback

To begin, orcas are placed into the Order Cetacea, a grouping which includes basically everything that can even remotely be referred to as a whale, This includes those with teeth like the orca, beluga, narwhal, and the dolphins, and those with baleen such as the right, gray, bowhead, and the rorquals. The distinction between the two groups are quite marked, which is why what's in a species' mouth is the deciding factor that splits Cetacea into two distinct Suborders. Suborder Mysticeti includes all of those whales with baleen, and Suborder Odontoceti includes all of the whales with teeth. Yes, I did just say whales with teeth. Odontoceti is also referred to as the "toothed whales" as that is exactly what the term "Odontoceti" means.

A killer whale skull

To many people, the term "whale" only applies to the large, majestic, baleen species that feed on minute organisms such as krill. This is where the argument that "orcas aren't whales, they're dolphins" comes in. Indeed, it is true that orcas are in the same Family (Delphinidae) as most of the species known as "dolphins." Depending on your interpretation of this, you can conclude that orcas are dolphins. However, the simple fact is scientists have placed such species as the dolphins and the orca into a grouping that is still referred to as whales. Thus, the statement "orcas aren't whales, they're dolphins" is rather a moot point as all dolphins are actually whales.

If this isn't enough evidence to make you agree that orcas are whales, consider the fact that phylogenetic studies always place whales, including the toothed ones, as grouping separate in relation to their next closest relatives, such as the hippo. Though the toothed whales and baleen whales did branch away from each other quite some time ago, they share a common ancestor (with teeth, mind you) that can only be called a whale.


Sources are Animal Diversity Web (University of Michigan), University of Bristol, National Oceanic and Atmospheric Administration, and National Geographic. Images are from Wikimedia Commons and are under Creative Commons licenses or copyright free: one, two, three.

Mismark Case Study: French Bulldog

This is another post I had drafted up. Since there was such a long gap between case studies, I decided to post this one as well.

A French bulldog is one of the breed's acceptable colors: cream.

The French bulldog standard is actually rather confusing in its definition of what is a "correct" color and what is not. This is what it actually says:

Acceptable colors - All brindle, fawn, white, brindle and white, and any color except those which constitute disqualification. All colors are acceptable with the exception of solid black, mouse, liver, black and tan, black and white, and white with black, which are disqualifications. Black means black without a trace of brindle. - AKC French Bulldog Standard

So, what it basically says that brindle, fawn, white, and brindle and white are acceptable plus any other colors except those listed. Which basically means no other colors.  My assumption is that the "other acceptable colors" includes such things as red, cream, sable, fawn piebalds, and dogs with masks. However, those could for the most part be included under the heading of "fawn." It would make much more sense to simply list the acceptable and unacceptable colors without the need to get so pointlessly wordy. Even worse is their wording on what is and is not acceptable pigment intensity to the skin and eyes. Namely, eyes must be dark and noses black except on lightly colored dogs. So, basically blue and liver aren't allowed, but according to this wording, a cream dog such as the one above could have a liver nose and be considered acceptable according to the standard. Anyway, on to the mismarks:

• Blue eyes
• Tan point
  
• Ticking
• White seen on dogs should be free of ticking spots
• Lack of stripes
• All black dogs must have at least one visible brindle stripe
• Non-black pigment
• Liver
• "Mouse" (apparently blue and Isabella/fawn)

This Frenchie has blue eyes

The exclusion of blue eyes in any standard that allows piebald dogs is...problematic. This is due to the fact that it is far from uncommon for piebald dogs to end up with blue eyes, particularly if one of their eyes is partly or completely surrounded by white. Dogs that are extreme white (aka extreme white piebald) are even more likely to have one or two blue eyes since the gene greatly increases the likelihood that the dog will have little to no white on its face. Both genes can and do occur in the breed quite frequently.

A black and tan dog

Tan point is quite unusual in the breed, but does pop up on occasion. Since it is a recessive gene, it can potentially be hidden under a wide variety of colors. Sable is dominant to tan point on the Agouti locus, and thus it is possible that sable dogs may carry the gene. Recessive red, which is seen in the breed, can hide every other color, including black and tan. It's also possible that some of the dogs identified as "black" or very heavy brindles could actually be tan point. This would be due to the layering you get between the Agouti locus (and thus tan point) and the black K locus (and thus brindle). Heavy brindle markings would make it nearly impossible to see the crisp tan markings that are present in the dog at left and would instead cause a dog to have few, if any, tan stripes visible on the legs.

This puppy has ticking

Ticking, though not addressed in the official standard, is seriously frowned upon by breeders, showers, and exhibitors. Ticking is caused by a dominant gene that is only visible on a dog with white markings. As such, any solid dog that has a copy of the gene is indistinguishable from solid dogs that don't. If a solid dog that carries piebald is crosses with a piebald or another carrier and that solid dog has a copy of the ticking gene, you would get surprise ticked puppies. Since it isn't even mentioned in the standard, I don't know why it would be frowned upon in the first place since "all other colors are acceptable."

A possible black Frenchie

The lack of stripes thing is also a bit odd, particularly when it comes to the preferences that are seen within the breed. Among the brindles, those that are mostly black are preferred. So, basically the fewer the stripes the better. Yet a solid black dog isn't okay? To be allowable, there has to be at least one tan stripe visible on an otherwise black dog. Having a single tan mark means the dog is basically black.

A black and white Frenchie

Moving beyond my earlier point about dark brindle and the tan point gene, piebald throws a bit of a wrench into the works. Since the preference is for dark brindles, the more white a dog has, the more likely that what few tan stripes it may have are hidden by that white. I would suspect that there are more French bulldogs that are disqualified for being black that have white markings than those that do not. I would also say that most people that are outside of the French bulldog breed would look at a lot of the show dogs that are out there and call them black. Even if some of the dogs that are disqualified for being black are genetically black, it's still quite possible that their appearance could be a surprise. Since recessive red is seen in the breed, it's quite possible that some of the recessive red dogs out there are hiding the dominant black gene.

It is also quite possible that black in French bulldogs is actually recessive black (which is on the Agouti locus), in which case any dog could be carrying the gene. If the right two dogs come together, then a surprise black could appear. The only gene that would prevent a dog with two copies of the recessive black gene from being visibly black would be the recessive red gene.

A liver Frenchie

A blue puppy

Finally, there is the disqualification of dogs with pigment other than black. Both the liver gene and the blue gene are recessive, and thus can be carried by practically any dog. The "mouse" color that is mentioned in the standard appears to refer to both blue dogs and dogs that are expressing both blue and liver at the same time, which is in other breeds known by such names as grey, fawn, Isabella, lavender, and lilac. However, the lilac coloration is seen least often of the three due to the need of the dog being homozygous recessive for both the liver and blue genes. As such, it's quite possible that "mouse" refers only to blue and the liver+blue lilac is completely ignored by the standard. This is what is implied by the French Bulldog Club of America. This amuses me somewhat since lilac can appear quite similar to fawn in color and since the standard allows for light pigment in light colored dogs, it's possible that a lilac could be considered acceptable.

A blue masked fawn

Anyway, such things simply distract from my overarching point. Except for a small possibility of blue dilution alopecia, there is nothing health-wise that would give a reason behind the exclusion of any of these colors from the standard. Thus, there really isn't any reason to exclude any of these "mismark" colors. The French bulldog is a companion breed, and as such arguments cannot be made for its working ability. However, color doesn't affect a dog's temperament, which is the biggest concern in a breed that is meant to be a companion.

Health in the breed is of even greater concern. The French bulldog has a number of issues, including serious breathing problems and a large number of their dogs being unable to give birth naturally. While these are caused by selection for short faces, large heads, and small hips, other problems are caused by a lack of genetic diversity in the breed. This list includes vertebral issues, luxating patella, and allergies. The vast majority of such issues are inherited and the reason why they become common in purebreds is due to selection and breeding methods. Heavy selection narrows genetic diversity by dropping dogs out of the gene pool entirely. By selecting for color, dogs who may be very healthy are being removed from a population due to a silly aesthetic reason. This has the potential of being very problematic for the breed.

Sources are the American Kennel Club, French Bulldog Club of America, Absolut Bullmarket French Bulldogs, and D'Accord Frenchies. Images are from Wikimedia Commons and Flickr.com under Creative Commons licenses: one, two, three, four, five, six, seven, eight, nine.

Mismark Case Study: Shar-pei

Thanks to the new Blogger I wrote this post a while ago, but forgot about it after it was buried under a number of other posts. I used to keep my unpublished posts always visible, so it's taking a little time to get used to.

A show dog in perhaps the most commonly seen color in the breed: red. The standard allows all shades of red to include cream, black, blue, liver/chocolate/brown, Isabella/lilac/fawn, and sable.

A bone mouth shar-pei

To the Western world, our knowledge of this rather unusual looking breed is usually restricted to the type seen in the show dog above. However, a number of traits can vary greatly. Overall, the breed can be split into two major types: meat mouth and bone mouth. Meat mouth dogs are like the one above: heavily wrinkled with a puffy muzzle and lost of excess tissue overall. In contrast are the bone mouth dogs, considered to be a better representation of what the breed once was, which has far less wrinkle and less exaggerated tissue overall.

Another point of variation that many people aren't aware of are the coat variations and color variations. There are three coat types: horse, brush, and bear, with bear being disallowed by the standard. In addition, there are a wide variety of colors. The vast majority are acceptable, but a few are not. Here are the mismarks:

• A non-solid color other than sable 
• Flowered (aka piebald, parti-color, spotted)
• Brindle
• Black and tan
• Albino

Though these are all mentioned in the standard, some are far more common than others. Albino, for example, may not even be present in the breed, let alone dogs in general. If it is, it's likely to be nearly indistinguishable from very pale cream dogs with skin diluted by both the liver and blue genes. If the gene is present, it's a simple recessive for which carriers cannot be easily distinguishable from non-carriers. Brindle and black and tan are quite unusual, but do still occur on occasion. Brindle is dominant to non-black/brindle (aka sable), but would be hidden by dominant black and recessive red. Black, though on the same locus, is dominant over brindle. Recessive red hides any and all black pigment that would have otherwise been expressed. Both of these genes are known to occur in the breed. Black and tan, in contrast, can be hidden by basically every other color seen in the breed. It's recessive to sable as well as hidden by dominant black and recessive red. Since all of these things are true, it makes it quite likely that the genes will never disappear from the population. Instead, they will remain hidden until the right cross causes the color to pop up.

Flowered liver

Flowered, by far, is the most common and well known of the shar-pei mismarks. It's caused by a couple of recessive genes: piebald and extreme white. The acceptable colorations according to the standard are all genetically solid. However, considering how common the flowered coloration is, quite a number of these dogs also carry a copy of either the piebald or extreme white genes. When the right two dogs come together, they will produce puppies with white.

Flowered red

I have also found evidence for the occasional dog with a copy of the Irish white gene, which produces the marking pattern most often associated with such breeds as the border collie. Some shar-pei breeders do not consider this coloration part of the "flowered" term. However, since the coloration is also a mismark for the same reason as the dogs with more white, I prefer placing them in the same category. It also appears that a very large portion of the flowered shar-peis you will find are also ticked. As such, the breed as a whole likely has quite a number of individuals that are genetically ticked, but this can't be seen due to a lack of white markings.

Flowered black

The reason why flowered dogs pop up so frequently is likely due to the breed's history as part of the dog fancy. Like so many breeds, only a small number of dogs were used in the creation of the lines that continue to be bred today in countries like the United States. According to analysis by one breeder, due to the small gene pool basically every single shar-pei that exists today is related to a flowered dog. This makes it rather likely that they will themselves carry the gene. In fact, it's estimated that one third of the population are carriers. The color remains fairly controversial, partly since the reasons for its exclusion from the standard are rather ambiguous.

Flowered red with a blue mask

All in all, there really is no reason that flowered dogs should be considered unacceptable in the shar-pei breed. One of the biggest reasons to allow the color comes down to genetic diversity. Shar-peis suffer from a startlingly large number of inherited diseases that have come from their small founding population and selection against certain colors and characteristics and for the exaggerated, wrinkled type that is so well known today. It's really quite amazing. Since this is such an issue, and so common at that, genetic diversity if precious. It's likely that there have been many flowered dogs who are far healthier than some of the dogs that are ancestors of the dogs you see in shows today. It's unfortunate that a silly aesthetic preference has led to the irreplaceable loss of genetic diversity. In the shar-pei, out-crosses could go a long way in trying to alleviate these genetic issues, and such groups as bone mouth shar peis and mismarked meat mouth shar peis could be very helpful additions to the gene pool.

Sources are American Kennel Club, Chinese Shar-Pei Club of America, University of Saskatchewan, Royal Shar-Pei, and Jewel's Shar-Pei. Images are from Wikimedia Commons or Flickr.com and are under Creative Commons licenses or are copyright free: one, two, three, four, five, six.