English Greyhound

The world’s three main registries give three different descriptions of the Greyhound — and the discrepancy between them is not an error but a consequence of documents being updated at different rates. A standard is the primary source for what is written in it. But it is a registry’s position, not the result of a measurement, and that is exactly why it helps to see all three texts side by side.

The most visible discrepancy is the minimum height for females: the FCI says 68 cm, the British Kennel Club says 69 cm. This is not a typo, and these are not different breeds. The FCI text was fixed in its 2010 edition and has not been revised since, while the KC updates its standards regularly: the current Greyhound revision is dated August 2025. When two documents describe the same dog fifteen years apart, a gap of one centimeter is exactly what you would expect.

The second difference matters more to a breeder. The FCI color list includes fallow — a separate dull sandy shade that simply does not exist in the British text. The same dog can therefore be described in its pedigree by a color the other registry does not recognize. The AKC removes the question altogether: in its standard, color is “immaterial” — of no consequence for judging.

And the third point, the most practical one: neither the FCI nor the Kennel Club gives a weight at all. The only one of the three registries that does is the American AKC, and it does so in pounds: 65–70 for males and 60–65 for females. Mirror image: the AKC gives no height. So any “official Greyhound weight in kilograms” is always somebody’s retelling of the AKC, not the text of a European standard. In the breed card at the top of this page we have labeled where each number comes from.

The Greyhound’s history is that rare case where the prettiest episodes turn out to be the least supported. Let us take apart the two that travel from text to text.

Egyptian origin

The historical note inside the FCI standard traces the breed to ancient Egypt, and images of long-legged dogs in tombs do exist. The trouble is that a fresco records a phenotype, not a breeding line. Genetic work on sighthounds shows a different picture: the “sighthound” type — long limbs, deep chest, narrow head — arose independently in several regions, as a convergent answer to the same task of chasing prey by sight. The resemblance between a silhouette on a tomb wall and the silhouette of a modern Greyhound does not prove kinship between them.

The law of King Canute

The second story, the one every article about the breed loves: the law of 1016 that supposedly barred commoners from keeping sighthounds and thereby preserved the purity of the blood. The document it rests on — the so-called forest laws of Canute — is recognized as a twelfth-century forgery, put together more than a hundred years after the king’s death. We have taken this episode off the page and suggest treating it as literary material rather than as the legal history of the breed.

What is documented solidly is the British chapter. It was in Great Britain that the standard took shape, that coursing and track racing were organized, and it was from there that the breed spread around the world in its modern form. All three registries name Great Britain as the country of origin, without disagreement.

The Greyhound is a large but remarkably light dog of aerodynamic build: a deep chest, a tucked-up belly, long muscular legs and a thin short coat with no undercoat.

The Greyhound’s body is a triumph of functional anatomy. Every curve works to minimize air resistance and maximize thrust. It is a big dog, yet it never looks heavy.

• Head: Long, narrow, with a flat skull. The ears are small and rose-shaped (rosette); they lift when the dog is excited, but usually fold back against the head for better aerodynamics.
• Body: Defined by a deep rib cage (room for large lungs and a big heart) and a strongly tucked-up belly. The back is broad and muscular.
• Legs: Long, powerful. The hind legs carry incredibly developed thigh muscles that work like springs.
• Coat: Short, fine, close-lying. It has no undercoat, which leaves the dog vulnerable to cold (we cover that separately).

What happens in the turn

The most interesting biomechanics of the Greyhound are not on the straight but in the bend. Usherwood and Wilson (Nature, 2005) measured that on the curve of a racing track limb loading rises by about 65% compared with the straightaway. And the dog holds the turn not by leaning and not by the grip of its feet on the ground, but by the moment its hip muscles generate. That explains two practical things: why sighthound injuries are so often tied to turns specifically, and why a healthy pet Greyhound is better off building speed on a straight stretch than carving circles inside a small fenced yard.

One more thing should be said about that same paper. It is often cited for a top-speed figure — while what it actually studied is limb loading in the turn. The Greyhound’s speed was measured by other researchers, and that is the subject of the next section.

In a peer-reviewed measurement (Hudson et al., Journal of Anatomy) the Greyhound’s top speed is about 17 meters per second — roughly 61 km/h. That is the number we are willing to put our name to.

Now compare it with what the standard itself claims. The historical note of the FCI says the Greyhound reaches “over 45 miles per hour” — about 72 km/h, that is, roughly seven miles per hour more than the measured value. The figure from the standard’s note has spread across hundreds of sites and until recently stood on this page too; we replaced it with the measured result and left both versions side by side, so that the reader can see where the discrepancy comes from.

The difference is not academic. 61 km/h is the speed at which a dog covers one hundred meters in about six seconds. No person, no leash and no fence of the “he’d never clear that” variety has time to react to a start that begins with a glance. It is from this figure that the main management rule of the breed follows, and we come back to it below in the training section.

The FCI and Kennel Club standards describe the Greyhound as a dog of “remarkable stamina and endurance.” Peer-reviewed physiology describes it as a sprinter, capable of one powerful and very short burst. This is a direct contradiction, and it is the most important thing to know about the breed.

Let us go through the evidence from the physiology side — there are three pieces of it, from different decades and different laboratories.

• Muscle composition. Guy and Snow (1981) showed that in Greyhound skeletal muscle practically 100% of the fibers have high ATPase activity — these are “fast” fibers, built for power rather than for prolonged work. At the same time the activity of 3-hydroxyacyl-CoA dehydrogenase, the enzyme needed to oxidize fat, is reduced in them. In plain words: the fuel that distance runners work on is fuel the Greyhound uses poorly.
• What happens over 800 meters. Dobson (1988) measured that after a distance of 800 m the lactate content in Greyhound muscle rises 6–7 times, while intramuscular pH falls to 6.40. This is a state of deep anaerobic acidification — exactly what makes continuing the run impossible.
• What happens over 100 meters. Pellegrino (2018) showed that even one hundred meters raise blood lactate from 1.70 to 9.08 mmol/L. A distance that most dogs do not even notice is already metabolically expensive for a Greyhound.

The practical conclusion for an owner is paradoxical and pleasant: the Greyhound is not the dog you have to run with for hours. Two short walks a day plus the chance to open up a few times a week in a fully fenced area cover its exercise needs. Trying to turn it into a partner for long runs works against its own physiology: it will give you the burst, and then spend a long time recovering.

The heart: constitution, not training

Schoning (1995) examined 230 Greyhounds at necropsy and obtained a heart-mass-to-body-mass ratio of 1.3% in females and 1.2% in males. The key detail in that work is not the numbers themselves but the fact that the ratio did not depend on whether the dog had raced. The big heart of the Greyhound is a constitutional trait of the breed, not a consequence of training.

For an owner this has an entirely practical consequence: a Greyhound’s heart can look enlarged on a radiograph and be completely normal at the same time. If the veterinarian is seeing your dog for the first time and has no experience with the breed, it is worth mentioning this feature before the workup for an “enlarged heart” gets started.

Newcomers to the dog world often confuse the similar-looking breeds of the sighthound group. The Greyhound is the “happy medium” in size, but it has close relatives too. If, for example, you are looking for a dog like a Greyhound only smaller, the Whippet is worth your attention. It is effectively a scaled-down copy, ideal for city apartments. And if even the Whippet seems too big, there is the Italian Greyhound — the smallest of the sighthounds, weighing less than 5 kg yet keeping all the grace of its larger cousins.

The comparison with the Whippet deserves a line of its own. It is almost the same body plan at a smaller scale — and yet, by the large longevity study (McMillan et al., 2024), the median lifespan of the Whippet is 13.4 years against 11.5 for the Greyhound. Two sighthounds of nearly identical construction live different lengths of time, and the reason for that difference is not in the build.

At the other end of the spectrum stands the stately Scottish Deerhound. Unlike the smooth-coated Greyhound, the Deerhound has a rough coat and was bred to hunt deer in the harsh conditions of Scotland. The Greyhound is a sprinter of the flatlands. We will come back to the Deerhound below: it is in that breed that the genetic cause of the postoperative bleeding so often attributed to the Greyhound was found.

By temperament the Greyhound is a quiet, gentle and reserved introvert: it barely barks, does not guard and lives easily with people, but it has a strong prey drive toward anything that moves fast.

A widespread myth holds that Greyhounds need enormous amounts of exercise and constant running. As shown above, physiology says the opposite. At home these dogs behave astonishingly quietly, almost invisibly. They rarely bark, adore soft surfaces and often try to burrow under their owner’s blanket.

Traits of character that matter:

• Reserve: Greyhounds are often indifferent to strangers. They will not jump on guests out of sheer joy the way a Labrador does, but they will not show aggression either.
• Sensitivity: These are emotionally vulnerable dogs. Shouting or harsh discipline can push a Greyhound into a state of stress. They remember being wronged.
• Prey drive: This is the most important point. The Greyhound is a sight hound: it hunts by eye. Anything that moves fast (a squirrel, a cat, a small dog, a plastic bag) is automatically read as prey.

This chase instinct separates them fundamentally from scent hounds, which work with the nose. The English Foxhound, for example, can follow a trail for hours without ever seeing the quarry, while a Greyhound reacts instantly to a visual stimulus. Owners should be careful about off-leash walks in open country.

Are Greyhounds aggressive?

The racing muzzle is regularly misread, so let us say it plainly: the racing regulator’s rules name a single reason the dog runs muzzled — preventing bites in a pack of dogs finishing side by side. The popular version, “so the dogs can be told apart in the photo finish,” is not supported by the rules. In ordinary life Greyhounds are not aggressive toward people. Many confuse their muscular power with fighting potential. Unlike the American Pit Bull Terrier, which may show animal aggression or guarding qualities, the Greyhound is a hunter, not a fighter and not a guard. It is more likely to fall asleep on a burglar than to stop one.

A Greyhound is entirely trainable, but it is harder to train than the working breeds: it is independent, it gets bored with repetition fast, and it works for a reward rather than “for its owner’s sake.” This is neither stubbornness nor a lack of intelligence — for centuries sighthounds were selected for the ability to make their own decisions in the field, not to carry out a handler’s commands. So the key to teaching them is short (5–10 minutes), playful sessions with high-value treats, without pressure and without shouting.

The hardest and most important cue is the recall. Because of that instantaneous reaction to movement, no Greyhound has a 100% reliable recall in open country: the moment it sees a rabbit or a cat it is gone before you can call. Go back to the figure from the speed section: 17 meters per second is the distance the dog covers while you are drawing breath to shout. That is exactly why the golden rule of the breed is to let it off leash only inside a fully fenced area, with no “there is nobody here anyway” exceptions.

Basic obedience (place, down, walking on a loose leash) comes easily to sighthounds, because more than anything they love calm and comfort. Conditioning for a calm exam works well too: since this breed has more veterinary handling ahead of it than the average dog — from toothbrushing to routine checkups — a dog that lets you look at its mouth and feet without a fight saves both sides years of nerves.

A separate topic is adjusting to household life in former racing dogs: having spent their whole lives in kennels, they may never have seen a slippery floor, a mirror or a glass door, and may not know what stairs are. Patience in the first weeks decides everything.

Keeping a Greyhound is different from caring for an ordinary shepherd dog or a spaniel. Here are the three things that really determine the quality of life of this breed — and the most important of them is not the one usually talked about.

Teeth: the real main problem of the breed

According to the VetCompass program (O’Neill et al., 2019), periodontal disease was recorded in 39.0% of Greyhounds against 9.3% across all breeds together. That is four times the general level and, on the available data, the most common documented problem of the breed — noticeably more frequent than anything usually listed among “Greyhound diseases.”

The practical consequence is simple and unpopular: daily toothbrushing for a Greyhound is not a hygienic detail but the core care procedure, more important than everything else in this section. Start on day one in the home, and for a former racing dog in the first week of adjustment. Regular veterinary exams of the mouth also make sense to schedule more often than “once a year along with the shots.” One more argument: a dental cleaning in a Greyhound means anesthesia, and anesthesia in this breed has its own particulars (the section below), so it is smarter not to let things get that far.

Temperature

The Greyhound has a very thin coat with no undercoat and little subcutaneous fat. That means it feels the cold about the way a person without clothes does. In winter, in fall and even on cool spring mornings the dog needs a coat — this is not a fashion whim.

With heat the situation is symmetrical, and here there are measured data. McNicholl and colleagues (2016) tracked the body temperature of Greyhounds after a run: on average it rose by 2.1 °C. Dark dogs heated up more than light ones — +2.2 against +2.0 °C — and the difference proved statistically significant (p = 0.005). For the owner of a black Greyhound that means something simpler than any theory: in hot weather his dog needs more shade, more water and shorter bouts of activity than the fawn neighbor on the same field.

Paw pads and corns

Hard keratin growths in the paw pads — the so-called corns — are described in Greyhounds. They grow into the pad and cause severe pain when the dog walks on hard surfaces. Annual prevalence on the available data is 2.4% — not a mass phenomenon, then, but for an individual dog the difference between limping and not limping. The cause of corn formation still has not been established, so there is no universal prevention either: what remains is regular inspection of the feet and attention to sudden lameness on hard ground.

By the largest study of canine lifespan to date (McMillan et al., Scientific Reports 14:531, 2024; sample of 584,734 dogs) the median lifespan of the English Greyhound is 11.5 years (95% CI 11.4–11.6).

On its own that is a normal figure for a large dog. The interesting part begins with the comparison. In the same work the median for mixed-breed dogs is 12.0 years, and the hazard ratio for the Greyhound is 1.19. By this sample, then, the breed lives somewhat less long than dogs of mixed origin, not longer.

And a second reference point, more telling still: the Whippet — effectively the same construction at a smaller scale — has a median of 13.4 years. Almost two years of difference between two breeds with the same body plan.

We put this in a section of its own on purpose. The idea of the Greyhound as a long-lived breed rests on one real fact — rare dysplasia — and on an unstated assumption that a long life automatically follows from it. The McMillan data do not confirm that assumption. That is why we do not use evaluative wording in the breed description: where there is a number we give the number, and where there is no number we do not put an adjective in its place.

This is the most practical section on the page. A healthy Greyhound steadily falls outside the all-breed reference limits on several values at once — and a veterinarian who does not know this starts treating a healthy dog.

Below are the breed reference intervals published by IDEXX (2025) from a sample of 220 dogs and built by CLSI methodology. An important caveat: these limits are given for IDEXX’s own methods. In another laboratory, with different analyzers and reagents, the limits may differ, so the table is a reason to talk with your veterinarian, not a basis for a conclusion of your own.

Read this table again through the eyes of a clinician seeing a Greyhound for the first time. High hematocrit, low platelets, low white blood cells, elevated creatinine and a low T4 add up — by all-breed limits — to a picture of several diagnoses at once. In the Greyhound this is normal.

Creatinine: muscle, not kidneys

Elevated creatinine in the Greyhound is a consequence of large muscle mass, not of kidney failure. Direct evidence came from Drost and colleagues (2006): the glomerular filtration rate in the Greyhound turned out to be higher than in dogs of other breeds — 3.0 against 2.5 mL/min/kg. The kidneys are not worse; they work harder. What helps tell “breed normal” from “real problem” is urine specific gravity: if the kidneys concentrate urine normally, a high creatinine by itself is not a diagnosis.

Thyroid: do not rush to hypothyroidism

Gaughan and Bruyette (2001) showed that Greyhounds have reliably lower basal T4 and lower free T4, while TSH does not differ from other breeds. That is the key to the diagnosis: a low T4 in a Greyhound does not by itself mean hypothyroidism. The diagnosis has to rest on three things together — a low T4, an elevated TSH and a clinical picture.

How widespread this is was shown by the work of Shiel (2007): in 91.3% of young untrained Greyhounds total T4 was below the all-breed normal range. The sample of untrained dogs is decisive here — it proves that this is a property of the breed, not a consequence of racing workloads.

Why Greyhounds are asked to be blood donors

Two reasons. The first is the high hematocrit from the table above. The second is blood types: among Greyhounds only 13% are DEA 1.1 positive, and that makes the breed a convenient blood source for the banks.

And here is a common confusion worth untangling. “Universal donor” and “DEA 1.1 negative” are not synonyms: universality is not defined by a single antigen, and among Greyhounds the share of genuinely universal donors is about 57%. So “my Greyhound is DEA 1.1 negative” does not yet mean “suitable for anyone”: typing is decided by the laboratory, not by the breed on the pedigree.

This is the information worth telling the veterinarian before the start of any procedure involving anesthesia — including a dental cleaning. Court (1999) formulated the practical rule that has since entered veterinary practice: thiobarbiturates are not used in Greyhounds. The acceptable options named are propofol, ketamine combined with diazepam, and methohexital.

The mechanism is enzymes, not “low body fat”

The most popular explanation — “a Greyhound has little fat, so the drug has nowhere to redistribute to” — does not hold up under checking. Two arguments from the studies themselves stand against it: oxybarbiturates of similar lipophilicity do not produce a breed difference, and induction of liver enzymes speeds up recovery. Both facts point to metabolism, not to distribution in tissue.

The molecular answer came from two papers. Martinez and colleagues (Scientific Reports 10:69, 2020) pointed to the enzyme CYP2B11, and a paper from 2024 (PLoS ONE 19:e0297191) pointed to POR (cytochrome P450 reductase). So the matter comes down to specific liver enzymes and to the variants of the genes that encode them.

The counterintuitive detail: “the racing dogs are the risky ones” is a simplification

You would think the metabolic peculiarities ought to concentrate in the racing lines. The data say otherwise, and in two directions at once. The CYP2B11-H3 variant occurs in 18% of racing dogs against 59% of show dogs. The POR-H3 variant is the reverse: 35% in racing dogs against 10% in show dogs. Two genes affecting the same system are distributed between the lines in opposite ways. So the simple rule “be careful with the racers” does not work: the caution belongs to the breed, regardless of whether a given dog ran on a track or walked in show rings.

What not to tell your veterinarian

The formula “Greyhounds metabolize drugs slowly” has become a convenient shorthand — and it is too broad. KuKanich and colleagues (2012) checked several drugs and showed that phenytoin, theophylline and diazepam behave within ordinary limits in Greyhounds. The metabolic peculiarity of this breed is substrate-specific: it concerns particular drugs, not the whole of pharmacology. The right sentence for the appointment sounds roughly like this: “this is a Greyhound; the breed has described peculiarities in thiobarbiturate metabolism and its own laboratory reference limits.”

A checklist for the veterinary visit

If you gather everything breed-specific from this page into one short list, you get exactly what is worth going over with the doctor before the procedure rather than after it:

• Anesthesia: no thiobarbiturates; among the acceptable options named are propofol, ketamine with diazepam and methohexital (Court, 1999).
• Lab work: the breed has its own reference limits — high hematocrit, low platelets and white blood cells, elevated creatinine, low total T4. The IDEXX table above works as a printout for the clinic.
• Kidneys: interpret a high creatinine together with urine specific gravity — in the Greyhound the glomerular filtration rate is higher, not lower (Drost, 2006).
• Thyroid: a low T4 without an elevated TSH and without clinical signs is not hypothyroidism (Gaughan & Bruyette, 2001).
• After surgery: schedule a check for the second day — late bleeding starts 36–48 hours out, and preoperative coagulation testing does not predict it.
• Heart: an “enlarged heart” on a radiograph in this breed calls for its own reading (Schoning, 1995).

The most dangerous breed feature of the Greyhound is not the surgery itself but the second day after it. Lara-García and colleagues (2008) described late postoperative bleeding in 26% of Greyhounds after neutering, with onset 36–48 hours after the procedure. For comparison, in other breeds the same figure in their observations was 0–2%.

The practical conclusion sounds mundane, but it is the one that saves dogs: the critical check is not on the day of surgery but on the second day. Bruising, swelling around the incision, lethargy, pale gums a day and a half after discharge — that is a reason to call the clinic, not to wait until morning.

What can be done about it

Marín and colleagues (2012) ran a randomized controlled trial in 100 dogs. In the placebo group bleeding occurred in 30%, in the group given aminocaproic acid (EACA) in 10%, a statistically significant difference (p = 0.012). This is one of the cleanest pieces of evidence in breed-specific veterinary medicine.

Dosing we deliberately do not give: in the available sources the recommended doses differ sevenfold, and the choice among them belongs to the veterinarian who operates, not to a page about the breed. This is our editorial decision, not a doubt about the drug itself.

The topic is not closed, at that. A retrospective study from 2024 on tranexamic acid (TXA) showed no effect — so the question of which antifibrinolytic and for whom remains a matter of discussion rather than a finished protocol.

Why standard lab work shows nothing

The most insidious feature of this condition: prothrombin time and aPTT in such dogs are normal. The preoperative coagulation panel therefore looks clean — and warns of nothing. The finding that does correlate with bleeding is a reduced antiplasmin level, that is, accelerated dissolution of a clot that has already formed.

Molecular confirmation of this mechanism exists: Court and colleagues (2023) found a causal variant in the SERPINF2 gene. One important caveat, usually lost in the retellings: that finding was made in Scottish Deerhounds, not in Greyhounds. Carrying the mechanism over to the Greyhound remains a reasoned assumption, not a proven fact, and we mark that plainly.

Most Greyhounds come into families not from breeders but through the adoption of former racing dogs: they finish their racing careers at 2–4 years old and then live another decade as affectionate pets. That makes the breed one of the few where an adult, already-formed dog can be taken on calmly — a sighthound’s character is stable, and there will be no “surprises of adolescence.”

Former athletes have their own quirks of adjustment. They are used to a strict routine and the company of other dogs, so the first days in the quiet of an apartment can leave them at a loss. Usually within a few weeks the dog “thaws”: it learns to play, discovers toys and for the first time in its life gets a soft bed of its own. Many adoption groups test such dogs in advance for compatibility with cats and children — that removes the prospective owner’s main question, so it is worth asking about the result of the test directly.

The veterinary side deserves separate preparation. A former racing dog often arrives with tartar — see the section on periodontal disease — and almost always has a spay or neuter still ahead of it. Both procedures have their own rules for a Greyhound: the anesthetic protocol and the check on the second day. The most useful thing you can do in the first week is find a clinic where they have already heard about the breed’s particulars, and bring them a printout of the breed reference limits.

How to read racing statistics

The racing industry is a sharp topic, and it is easy to get lost in the public argument around it. The useful thing to understand is this: the sides mostly disagree not about the data themselves but about the denominator and the boundary of the count. Injury rate “per race” and “per dog per season” are two different numbers describing the same reality, and they are not interchangeable. In the same way, in regulators’ reporting “left the registry” and “died” are two different populations, not parts of one whole. When you meet a striking figure, the first question to ask about it is not “true or false” but “divided by what, and what exactly was counted.”

Let us gather together everything taken apart above. The portrait of the owner who will do well with this breed is made up not of character traits but of living conditions.

A Greyhound will suit you if

• You live in an apartment and value quiet. This is the rare case where a tall dog is genuinely comfortable indoors: it barely barks and sleeps most of the day.
• You have access to a fully fenced area. Not a “quiet park” and not a “field with nobody in it,” but a fence. This requirement is not up for discussion, and it follows from that figure of 17 meters per second.
• You are ready to brush your dog’s teeth every day. Given 39% periodontal disease, that is not a wish but the core care procedure for the breed.
• You are fine with an adult dog whose character is already formed. Most Greyhounds come into a home through adoption after a racing career.
• You are ready to be the “translator” between your dog and the veterinarian — at least until the first appointment at a clinic where the breed is known.

It is worth looking for another breed if

• You need a partner for long runs. Greyhound physiology is built for the burst, not for the distance: one hundred meters already raises blood lactate several times over.
• There is a cat or small animals in the home. This is not an automatic no — many adoption groups test dogs for exactly this compatibility — but taking a Greyhound into a house with a cat sight unseen is not a good idea.
• You are looking for a guard dog. The breed has neither a guarding instinct nor a tendency to territorial behavior; the watchdog score in the breed card at the top is the lowest one there for a reason.
• You are not ready to dress your dog. A thin coat with no undercoat and little subcutaneous fat make clothing in cold weather part of care rather than an accessory.
• You need a dog for competitive obedience. Sighthounds were selected for centuries for making their own decisions, and a reliable recall in open country is out of reach for them in principle.

A set of striking claims circulates about this breed, copied from one text into the next. Being striking is a risk signal, not grounds for trust, so we checked each of them and took the most widespread ones off the page. Here they are, together with what is known instead.

• “The dog spends 75% of the gallop in the air.” A pretty figure that travels from site to site. That number is no longer on this page: we give only figures for which we can name a measurement. What has actually been measured about Greyhound movement is the +65% limb loading in the turn (see the section on aerodynamics).
• “A 270-degree field of view” and “sees for a kilometer.” A dog’s field of view overall is about 240–250°, and visual acuity is around 20/75 on the human scale, that is, noticeably lower than a person’s. The strength of the Greyhound is not in distance and not in the width of the field but in its reaction to movement: it launches at a moving object faster than it can make the object out.
• “The only breed mentioned in the Bible.” The claim rests on the English translation of 1611 (Proverbs 30:29–31). It is an artifact of that translation specifically: modern translations of the same passage give “rooster,” not “greyhound.”
• “The racing muzzle is there to tell the dogs apart in the photo finish.” The regulator’s rules name a single reason — preventing bites at the finish.
• “A Greyhound has less than 1% fat.” The figure comes from a measurement of dissectible fat — fat that can be separated by dissection. That is not the same as the percentage of fat in the body: a substantial part of the fat is distributed inside tissue and is not counted that way. The correct wording without a number: a Greyhound has very little subcutaneous fat — hence both its sensitivity to cold and the definition of its muscles.
• “Canute’s law barred commoners from keeping sighthounds.” The document is recognized as a twelfth-century forgery (see the section on history).
• “The Greyhound comes from ancient Egypt.” The FCI standard does say so in its historical note, but sighthound genetics point to the independent emergence of this type of dog in several regions.

One common claim, on the other hand, did survive the check, and with a number attached: a Greyhound really does have more red blood cells than the average dog. The hematocrit of 52–68.4% from the table of breed reference values is that same fact, only measured. It is this, and not the legend, that stands behind how often Greyhounds are asked to be blood donors.