If your dog produces a litter of “rainbow puppies,” with every puppy looking like a distinctly different type of dog, she might very well have mated with more than one male. That will be especially obvious if you bred your purebred female to a purebred male and ended up with puppies that definitely aren’t that breed. Then you recall she did briefly get loose during her heat cycle…. Canine Reproduction An intact female dog generally comes into heat twice a year, approximately every six months. Small breed dogs experience more estrus cycles, perhaps as many as four per year. Very large breeds, such as great Danes, might only come into heat annually. Most dogs reach puberty at about 6 months of age. You’ll notice a bloody discharge when the cycle starts, but your dog shouldn’t get pregnant at that stage. Between a week to 10 days into the cycle, when the discharge becomes watery, the dog ovulates. However, there’s no truly safe time during heat when she can’t get pregnant, because every dog’s body is different. Multiple Fathers Once female dogs start ovulating, egg release continues over several days. Sperm can survive in the reproductive tract for a week after mating. This means if your dog mated with one dog shortly before ovulation, she could still become impregnated seven days later. Breeders usually recommend two or three matings over a few days to ensure pregnancy. Accidental breedings with different males can just as easily occur over that time period. Avoiding Accidents The easiest way to make sure your dog doesn’t get pregnant is by having her spayed. If that’s not an option because you intend to breed her, ask your vet about prescription hormone medications that can act as canine birth control. When your female dog is receptive to males, not only will she want to get out of the house, but intact male dogs in the area want to get to her. You can’t leave your female dog unsupervised for even a brief period when she’s in heat, and that includes leaving her in your normally secure fenced-in yard. If you take her out for walks, she’s leaving clues that’s she’s available every time she pees. Even if you’ve bred her deliberately, with two or more matings with the same dog, as long as she’s still receptive some strange dog could try his luck. Registration The American Kennel Club, the governing body of purebred dog registration, shows and many canine sports in the United States, recognizes that puppies in a litter might have different dads. While the AKC allows multiple-sired litter registration, the fathers must be the same breed as the mother. In order to register such a litter, the AKC requires DNA testing for the mother, potential sires and all puppies. Once the AKC determines the sires of particular puppies, registration can ensue. If one of the sires was a purebred dog of the same breed as the mother and the other was a different or mixed breed, the AKC might register the purebred puppies if DNA of all parents and puppies is submitted.

If you don’t mind putting away your dark wardrobe, you can choose a white canine in any size. While some breeds have a variety of permissible colors in their conformation standards, at least 14 dog breeds are strictly white, with no spots accepted, according to standard.

Small White Breeds

Small white dogs include the Maltese and bichon frise, both bred for companionship. A less common breed, the Bolognese, resembles the bichon frise. The West Highland white terrier sports the curiosity and drive of the terrier. The Coton de Tulear is named for his cottony white coat. All of these dogs mature at under 15 inches in height.

Medium-Size White Dogs

Originally trained as circus performers, the American Eskimo comes in toy, miniature and standard sizes. The standard size is actually a medium-size dog, between 15 and 19 inches in height. This smart, foxlike dog excels in agility and other canine competitions.

Large White Dogs

Several large white dogs, those maturing over 19 inches tall, originated as sheep guardians. They tend to blend in with the flock. These include the Great Pyrenees, Turkish Akbash, Slovenský Čuvač, Owczarek Podhalansk, maremma, kuvasz and komondor. Sled-pulling was the original purpose of the Samoyed, a northern breed.

Dogs with normal foot physiology have four toes on the hind feet. Some breeds possess a fifth toe on the hind foot, commonly referred to as a dewclaw, but more accurately called polydactyly. Normally located higher up the leg from the other toes, it may or may not come into contact with the ground when the dog runs and plays.

An Evolutionary Throwback

Dogs normally considered to be “flock guardians” present an extra hind toe or dewclaw most frequently. These breeds would include the Anatolian shepherd, Australian shepherd, rottweiler, shih tzu, standard poodle, and many Asian breeds including the shiba inu, akita, jindo, sasparee and Korean tosa. The great Pyrenees is the most commonly known polydactyl canine, and may even present six hind toes. The Norwegian Lundehund may present five toes on both his front and hind feet. In a study supported by the Korean Research Foundation and the Korea Science and Engineering Foundation, scientists came to the conclusion that the presentation of a fifth toe, most accurately called polydactyly, is a reversion from the evolutionary loss of the toe.

Caring for Dewclaws

A polydactyl dog’s dewclaw may be attached by bone or solely by skin. Dewclaws may be removed surgically to prevent them from getting caught on objects, which can cause injury to the dog. If not removed, the toenail should be trimmed regularly to prevent it from causing sores or other injury to the rest of the leg and foot.

German shepherds are the dogs that most people would assume is the breed of choice to be drug sniffers. Despite their long history of being search and rescue and police dogs, they don’t have a monopoly on drug sniffing jobs. It’s true that their versatility and resourcefulness are useful for the task, but other breeds also possess natural characteristics that are vital for drug detection.

The Nose Knows

The top dogs used for sniffing out drugs, according to John J. Ensminger’s 2012 book “Police and Military Dogs,” are English springer spaniels and border collies. Other dog breeds that have shown an aptitude for sniffing out drugs include Weimaraners, Labrador retrievers, golden retrievers and Belgian malinois. Alternative to traditional purebreeds, it could be that the solution lies in a hybrid breed of dog. In her article “Super Sniffing Dogs” for DogChannel.com, D. Caroline Coile, Ph.D. revealed that Russian scientists claim to have created a breed with superior sniffing capabilities by crossing Russian huskies with jackals.

Mixed Breeds Can Sniff, Too

Purebred dogs aren’t the only ones who can do a stellar job of sniffing out drugs. Cross- and mixed-breed dogs can do it, too. They just have to display the right qualities and have the work ethic. Sometimes those characteristics can come from the genes of different breeds the dog has inherited, and sometimes an individual dog just has a talent for it.

Drug Sniffing Qualities

Mixed breed or purebred, the best drug sniffing dogs have a combination of qualities that work together to make them good at what they do. In addition to having an excellent sense of smell and hunting and tracking abilities, drug dogs need to be physically fit, independent, agile, love hard work and have a hunger for praise. They have to really, really want to do the job, too. Dogs of any breed who aren’t interested can easily become distracted from the task at hand.

Certifying a Narcotic Dog

A dog’s breed won’t keep him from becoming a certified narcotic dog, if he has the right stuff to complete the course. The Hornbecks.net standards for narcotic certification don’t even include a list of dog breeds who can test for certification. Instead, the requirements are that a dog must know how to alert his handler when he’s located stashed drugs, is limited to 10 minutes to find two different stashes and must show proficiency in searching a variety of areas, including indoor areas, outdoors and vehicles.

Chow chows are well-known for having distinctive blue tongues, although it’s not known why this trait occurs. Only one other breed of dog has an entirely blue tongue — the Shar-Pei. However, many other breeds can have spots or patches of blue on their tongues.

About Blue Tongues

Although usually referred to as blue in color, dark tongues on dogs can sometimes appear more like dark purple or black. It’s unknown why Shar-Peis and chow chows have completely black tongues, but it’s caused by extra dark pigment in the skin. In dogs who just have spots or patches of blue on their tongues, it could be likened to a birthmark on a human. In fact, dogs often have small patches of dark pigment on their skin — you just can’t see them through their coats.

Chow Chows

Chow chows are an ancient breed, possibly one of the oldest in the world. They’re known for their thick fur and cuddly, bearlike appearance, as well as for their blue tongues. Originating from China, they were kept in the Emperor’s imperial kennels. Chinese legend states that they got their blue tongues at the point of creation, when one chow chow licked drops of blue from the sky as it was being painted. Although often independent and aloof, they’re fiercely loyal to their families and can be very protective.

Shar-Peis

Shar-Peis are striking and distinctive dogs. Covered in wrinkled skin as puppies, they gradually lose some of their creases and folds with age. They’re known to be intelligent, brave, loyal and playful. Although they form close bonds with their families, they’re generally friendly and good-natured around strangers. It’s thought that their blue tongues occurred as a result of some chow chow lineage in the creation of this breed.

Other Breeds

While no breed of dog other than the chow chow and the Shar-Pei have fully blue tongues, many breeds and mixed-breeds are known to have some blue pigmentation on them, just a couple of spots or significantly larger patches. Breeds that may have some blue on their tongues include Akitas, Dobermans, Australian shepherds, Irish setters, mastiffs, Pomeranians, Dalmatians, Airedales, golden retrievers and Newfoundlands.

Masks aren’t just for superheroes; a number of dog breeds sport multicolored facial markings that give them a masked appearance. Large and small breeds alike may sport masks, and while this list does not cover all breeds, it gives a comprehensive overview of masked dogs.

Small Masked Breeds

Pugs are one of the most recognizable of all masked breeds. These jovial little dogs come in a number of colors, but the fawn and apricot with black masked markings are most common. The shih tzu also sports masked markings, although the mask may be any color that is different from the base color of the coat.

Medium Masked Breeds

The Siberian husky comes in a plethora of colors, and may be born with or without masks. Huskies tend to fade as they age, so a heavily masked puppy may mature into a minimally masked adult. The Australian shepherd is one of the most colorful breeds in the dog world, and their masks follow the same colorful trend. Aussie masks often come in black or tan like many other breeds, or may be a lighter or darker variation of the base coat.

Large Masked Breeds

German shepherds are known for their rich tan or red coats and black saddles, although many people do not realize that their characteristic black muzzles and ears are a variation of the masked gene. Great Danes also display masked coloration, which may be present in all coat patterns and color varieties.

Truffles, among the world’s most expensive delicacies, are fungi that grow under the soil and leaf litter at the roots of several tree species. They require dogs or pigs to find them. The Italian dog known as the Lagotto Romagnolo is specifically bred for truffle hunting, but other breeds are suited to learning the task. Not only must you train these dogs to find truffles, but you must train them not to eat the little fungus fruits. The same canines that hunt for truffles can also find morels.

Truffle and Mushroom Hunting

Any dog can potentially become a truffle or mushroom hunter, but not every breed is perfectly suited to the task. You can try out your dog’s skills at truffle hunting clinics held throughout the country. The training period for “professional” truffle hunting canines lasts between two and four months. If you want to purchase a well-trained dog specifically for truffle or mushroom hunting, expect to pay in the six figures.

Lagotto Romagnolo

Originally used as a water dog in the Italian marshes, the Lagotto Romagnolo has been used for truffle hunting since at least the 19th century. Between the end of World War I and the start of World War II, the breed was used by virtually all Italian truffle hunters. The medium-size, curly-haired canine appears in various shades of brown. Besides his keen nose for mushrooms, this smart dog is easy to train and makes a good family pet.

Detection Breeds

Dogs that shine at detection work often succeed in truffle hunting. These breeds include the German shepherd and Belgian malinois, dogs used by law enforcement and security agencies worldwide. Not only are these dogs talented truffle hunters, but they’re also smart and easily trained, and they possess a good work ethic. While scenting is paramount in truffle training, it’s of little use unless the canine is also obedient and cooperative. The same sort of discipline required for truffle hunting is needed for the more serious pursuits of bomb detection or search-and-rescue.

Sporting Breeds

Dogs bred specifically for sport, such as Labrador and golden retrievers, can excel as truffle hunters. So can various types of setters and pointers. Even beagles can make good truffle hunters, since they’re especially ruled by their noses. If you want to train a sporting breed for the task, choose a dog from field lines rather than from show lines: Breeders of the former make a special effort to pass on hunting talent in their dogs.