What's behind your cat's striking eye color

By Kim Campbell Thornton

It's not just the fur or the purr that cats use to hold us spellbound: It's those eyes. Whether they are blue, green, gold, copper or some variation of those shades, a cat's eyes are one of his most beautiful features. Here's how they come to be that way.

Eye color is genetically linked to coat color. Kittens are born with blue eyes, which may stay that way or change color as the kitten matures. For instance, all pointed cats have blue eyes. Cats who are solid white or mostly white may have blue, green, gold or copper eyes. The most common eye colors range from greenish-yellow to gold.

You may have heard that white cats are always deaf. Not necessarily. Some are, and some aren't. White cats with blue eyes are more likely to be deaf, however, than white cats with gold or green eyes.

Deafness is associated only with the dominant white gene, not the white spotting gene, says feline geneticist Leslie A. Lyons, Ph.D.

"There's a high association of dominant white with deafness and dominant white with blue eyes, and if you are dominant white with blue eyes, you're more likely to be deaf."

Between 10 and 20 percent of white cats with eyes of other colors may be deaf. White cats with only one blue eye may be deaf only in the ear that's on the same side as the blue eye.

Eyes with the brilliant copper of a shiny new penny or the bright green of an emerald usually are the result of selective breeding, but genes don't discriminate. Those eye colors can appear in cats without a pedigree as well. Pedigreed cats noted for their distinctive eye color include the Burmese, with large, round gold eyes; the tonkinese, with sparkling aqua eyes; the Egyptian mau, with gooseberry green eyes; and the Russian blue, with vivid green eyes.

Some cats have "odd eyes," meaning one eye is blue and one is green or gold. The scientific term for this is "heterochromia," from the Greek words "hetero," meaning "different," and "chromia," referring to color. The difference in color might not be noticeable in a kitten, but changes gradually as the kitten moves toward adulthood.

We usually see odd eyes in white cats or cats with the white spotting gene, such as bicolor and tuxedo cats. Breeds in which odd eyes are common include Turkish angoras and Turkish vans. A description of angoras stated that the eyes should be "as green as the lake and as blue as the sky." Other breeds that may sport odd eyes are Persian, sphynx, Oriental shorthair and Japanese bobtail cats.

Odd eyes occur when a dominant white gene (meaning it masks other colors) or a white spotting gene blocks the concentration and distribution of natural pigments within the iris tissues during development. It's unusual to see odd eyes in cats who lack both the dominant white and the white spotting genes, but it can happen.

An unusual and attractive look is the dichromatic, or dichroic, eye, usually seen in white cats. That's one with two colors in one iris. For instance, the eye might be half green and half blue or have a green iris encircled by yellow. One or both eyes can be dichromatic, sometimes with each eye mirroring the other. Even more rarely, only a section of the eye may be a different color. Think of a pie-sliced shape of brown in what is otherwise a blue or green eye. Those eyes aren't just odd; they're downright weird, but undoubtedly beautiful.

Q&A

Can dogs benefit

from cancer diet?

Q: My dog has been diagnosed with lymphoma. I've heard that there's a cancer diet that may help. What can you tell me about it? Are there any other dietary changes I can make? -- via email

A: Many pet owners hope that a change in diet can help pets with cancer. So far, little published research has been done in this area, so I'm afraid I can't tell you that there's a "silver bullet" feeding regimen that will cure your dog. But I can discuss cancer-related changes in metabolism and evidence-based approaches that are being looked at to help reduce or eliminate those problems.

Dogs with cancer may lose weight or experience muscle wasting as a result of chemotherapy or radiation treatment. It's really important to make sure they are able to take in nutrients and maintain a healthy weight as they undergo treatment. This can mean continuing to feed your dog his regular food that he likes and does well on, or switching to a particular commercial or homemade diet recommended by a veterinary nutritionist.

You have probably heard that a low-carbohydrate diet is beneficial to cancer patients. There's no strong evidence for that yet, but on the other hand, it can't hurt to try it, as long as you choose an appropriate food that contains less than 20 percent of its calories from carbohydrates. Bear in mind that a low-carb diet is not the same as a grain-free diet, which can still be high in carbohydrates, fat and calories. Ask your veterinarian to consult a veterinary nutritionist about appropriate choices.

We don't currently have specific nutritional requirements for dogs with cancer. The best thing you can do to help your dog recover is to continue to feed a food that will maintain his body condition and meet his energy needs during treatment. -- Dr. Marty Becker

Do you have a pet question? Send it to askpetconnection@gmail.com or visit Facebook.com/DrMartyBecker.

THE BUZZ

Dogs fetch help for

farmers with disabilities

-- Border collies, Labrador retrievers and other dogs are learning to help farmers with disabilities perform chores, thanks to a small group of volunteers called PHARM Dog USA: Pets Helping Agriculture in Rural Missouri. Founder Jackie Allenbrand evaluates farmers' needs, assesses farms and makes placements. She and other trainers teach the dog-farmer teams to work together. Tasks the dogs may perform include bringing or picking up tools, opening gates, carrying buckets, managing livestock, helping farmers brace themselves and going for help. The dogs, donated by breeders or acquired from shelters, are placed at no charge to farmers.

-- Pet owners will spend nearly $16 billion on veterinary care this year, estimates the American Pet Products Association. If you're considering purchasing pet health insurance, here are five things you should know: 1. Some insurers provide discounts to AARP or AAA members, active-duty and veteran military personnel or to customers who enroll two or more pets. 2. Some employers offer pet insurance as an employee benefit. 3. Policies are available for birds, reptiles and other exotic pets. 4. Older pets can be insured, usually until they are 12 to 14 years old, but policies may exclude coverage for age-related illnesses. 5. Policyholders can usually take pets to any veterinarian.

-- You're probably familiar with sighthounds -- dogs that hunt by sight, such as greyhounds -- and scenthounds -- dogs that use their sniffers to track quarry -- but did you know that some hounds are multitalented, able to hunt by both scent and sight? Sometimes called utility hounds, they include the Rhodesian ridgeback, basenji, pharaoh hound and Ibizan hound. Other versatile hunting dogs that are classified as hounds are the Finnish spitz and Norwegian elkhound, spitz-type dogs that were created to hunt game birds, elk and bear. -- Kim Campbell Thornton

ABOUT PET CONNECTION

Pet Connection is produced by a team of pet-care experts headed by "The Dr. Oz Show" veterinarian Dr. Marty Becker and award-winning journalist Kim Campbell Thornton. They are affiliated with Vetstreet.com and are the authors of many best-selling pet-care books. Joining them is dog trainer and behavior consultant Mikkel Becker. Dr. Becker can be found at Facebook.com/DrMartyBecker or on Twitter at DrMartyBecker. Kim Campbell Thornton is at Facebook.com/KimCampbellThornton and on Twitter at kkcthornton. Mikkel Becker is at Facebook.com/MikkelBecker and on Twitter at MikkelBecker.

CAPTIONS AND CREDITS

Caption 01: Multiple genes determine eye color. Position: Main Story

Caption 02: Always ask about exclusions, deductibles and possible provider restrictions before purchasing pet health insurance. Position: Pet Buzz/Item 2

Mischievous and curious, ferrets are a hoot to live with, but they have some special needs. Here's what to expect if you're planning to acquire one of the slinky critters

By Kim Campbell Thornton

In love with the furry tube of fun that is the ferret? These members of the mustelid family (hint: that means they're stinkers) are inquisitive and energetic -- think toddler-on-chocolate energetic. Their busy nature makes them entertaining companions, but it also means they get in to everything. As you can imagine, ferrets have some special needs, some that you might not be aware of. Here are 11 tips on living with them.

-- Ferrets are carnivores with higher protein and fat requirements than cats. Feed them a high-protein diet made for ferrets, and avoid sugary treats such as raisins and carrots. In a pinch, you can feed canned kitten food, but it's not appropriate as a full-time diet. Because ferrets can be prone to insulinomas (pancreatic tumors), it's best to avoid high-carbohydrate dry foods, recommends Scott Weldy, DVM, of Serrano Animal and Bird Hospital in Lake Forest, California. Choose a food that's at least 32 percent animal protein and 20 percent fat with minimal amounts of plant-based ingredients.

-- Ferrets are hunters. They can be great friends with cats and dogs, but pocket pets and birds aren't safe around them. On the plus side, you won't have a problem with mice, rats or other vermin in your home.

-- Ferrets have sharp, pointy teeth, and they can be nippy in play. Supervise their interactions with young children, and protect valued items. Grandma's piano can make a fine ferret chew toy if you don't keep Ferdinand away from it and give him acceptable items to play with.

-- Ferrets steal stuff. "They are worse than any 2-year-old," says Kristi Krause, DVM, who also practices at Serrano Animal and Bird Hospital. "They will take off with your car keys. Your wallet is gone. Your slippers are gone."

-- Ferret-proofing a home is a difficult art. Ferrets fit through tiny spaces. Never assume they can't get to something or get in or out of a certain area. If they can squeeze their head through an opening, the body will follow. And of course they can use their paws to manipulate objects. Don't be surprised to find your ferret inside the dishwasher or in the back of your kitchen cabinets.

-- Ferrets need large living quarters for when you're not home to keep them out of trouble. Choose a cage that's at least two feet wide and four feet high with two or more levels. Flooring or bedding can range from carpet or wood to pine shavings or artificial grass, but get rid of anything your ferret chews up.

-- Ferrets are nocturnal, but they will adapt to your schedule. When they're not playing hard, they're sleeping hard, up to 16 hours a day.

-- Ferrets enjoy playing on large exercise wheels and running through tunnels. An easy, inexpensive option for a tunnel is a flexible clothes dryer vent, Dr. Weldy says. Ferrets will play in them all day, especially if you toss treats inside for them to find.

-- Ferrets smell. With their noses, of course, but they also have an odor, unique to each animal, produced by their musk glands. Some people like the scent; some don't. Be sure you can live with it before getting a ferret.

-- Ferrets need distemper and rabies vaccinations as well as flea and heartworm preventives.

-- Ferrets must be spayed or neutered or have birth control implants. Spaying protects a female ferret's health by limiting the secretion of estrogen, which at high levels can cause fatal anemia. Altered ferrets stink less, and neutered males have less aggressive behavior.

Ferrets can bring their people many hours of joy, but they're not for everyone.

"I think you have to be a special person to be tolerant of their behaviors," Dr. Weldy says. "They're unique animals."

Q&A

Unusual behaviors may

signal health problems

Q: I always hear that when pets are acting out, you should take them to the veterinarian to see if there's anything wrong with them. What kinds of health problems can cause behavior changes? -- via Facebook

A: You name it! Behavioral changes are sometimes the only way we have of knowing there's an underlying health problem. Behavior changes can help us recognize pain, infections, tumors, degenerative conditions, nutritional deficiencies, metabolic diseases, gastrointestinal problems and skin diseases.

For instance, behavior changes that may indicate pain include decreased activity or social interactions; vocalizing more or less than normal; biting or licking at a joint; or breaking housetraining. Cats may groom themselves less often.

Behaviors that might indicate neurological problems include sleeping more than normal, circling, pressing the head against a wall or other solid surface and changes in personality. Many people associate seizures with convulsions and loss of consciousness, but other types of seizures can cause behaviors such as fly biting, chewing, tail chasing and aggression. Pets with neurological symptoms may be suffering from infections, types of cancer, toxins, epilepsy, cognitive dysfunction or metabolic disorders.

Metabolic diseases such as hyperthyroidism in cats can cause pets to be irritable or aggressive, unusually active, unusually hungry or unusually vocal. Dogs with hypothyroidism may seem anxious, eat less and sleep more. Pets with diabetes or kidney disease may have accidents in the home because they're drinking more water than usual.

Pets with painful gastrointestinal problems may show such signs as excessive or unusual licking, sucking, lip smacking, gulping or chewing. Itchy or painful skin diseases and food allergies may cause them to bite or chew at themselves.

If you're lucky, your pet's unusual behavior will turn out to be a one-time aberration, but it never hurts to get it checked out to make sure nothing serious is going on. -- Dr. Marty Becker

Do you have a pet question? Send it to askpetconnection@gmail.com or visit Facebook.com/DrMartyBecker.

THE BUZZ

Missing parrot returns

with new language

-- African grey parrot Nigel was a California bird, but he spoke in the same British accent as his owner, Darren Chick. The bird escaped from his home in 2010, but was found last October and returned to Chick, thanks to his microchip. Chick recognized Nigel immediately, but was surprised by his new vocabulary. Nigel was speaking fluent Spanish, and his British accent was gone. Turns out he'd been found by a Spanish-speaking family, who came forward after seeing news stories about "their" lost bird's return to his original owner. Happy ending: Chick decided to give Nigel to them after hearing how heartbroken they were at his disappearance.

-- Dogs with confirmed mammary cancer and osteosarcoma, as well as some other cancers, may be eligible to enroll in a study of a cancer vaccine at Veterinary Cancer Center in Norwalk, Connecticut. The study is run by Gerald Post, DVM, of VCC, and Mark Mamula, professor of medicine at Yale School of Medicine. They hope the vaccine can be an effective treatment for dogs -- and eventually humans. Use of the vaccine does not interfere with other forms of treatment, such as surgery or chemotherapy. More information is available from clinical trial coordinator Gillian Rothschild, Gillian@VCCHope.com.

-- Watching fish is calming and distracting, boosts your mood and lowers blood pressure and heart rate, research shows. Scientists at Great Britain's National Marine Aquarium, Plymouth University and the University of Exeter measured the heart rate and blood pressure and assessed the mood of volunteers as they watched tanks with gradually increasing numbers of fish. The more fish, the better, they found. "This study has, for the first time, provided robust evidence that 'doses' of exposure to underwater settings could actually have a positive impact on people's well-being," says Deborah Cracknell of the National Marine Aquarium. -- Dr. Marty Becker and Kim Campbell Thornton

ABOUT PET CONNECTION

Pet Connection is produced by a team of pet-care experts headed by "The Dr. Oz Show" veterinarian Dr. Marty Becker and award-winning journalist Kim Campbell Thornton. They are affiliated with Vetstreet.com and are the authors of many best-selling pet-care books. Joining them is dog trainer and behavior consultant Mikkel Becker. Dr. Becker can be found at Facebook.com/DrMartyBecker or on Twitter at DrMartyBecker. Kim Campbell Thornton is at Facebook.com/KimCampbellThornton and on Twitter at kkcthornton. Mikkel Becker is at Facebook.com/MikkelBecker and on Twitter at MikkelBecker.

CAPTIONS AND CREDITS

Caption 01: Ferrets can learn to use a litter box and walk on leash. Position: Main Story

Caption 02: Watching fish in aquariums is one way to bring the stress-relieving benefits of nature indoors. Position: Pet Buzz/Item 3

Do you know how to prevent dog bites? Here's some expert advice

By Kim Campbell Thornton

It's easy to find information on the signals dogs give before they bite and ways to prevent dog bites. But a recent study published in the Journal of Veterinary Behaviour found that educating people about canine body language and high-risk situations isn't enough. All too often, people believe dog bites won't happen to them or that their dog won't bite, and they ignore a dog's warning signs.

"Nobody wants to believe that their beloved dog would cause harm, but all dogs have the potential to bite, whether it be in aggression or in play," says Carri Westgarth, Ph.D., a dog behavior expert at the University of Liverpool's Institute of Infection and Global Health. She and other researchers suggest that raising awareness of that reality is an important part of successful dog bite prevention.

What are the situations in which bites are most likely to occur, either to people or other animals? Trainer and expert witness in dog bite cases Jill Kessler-Miller of Palos Verdes, California, notes the following:

-- When dogs are off their leash and off their property.

-- When people carelessly permit dogs on extendible leashes to roam.

-- When children and dogs are left unsupervised.

Dog bite attorney Kenneth M. Phillips of Beverly Hills, California, says other common situations that invite bites involve unsupervised children entering a yard with a dog or dogs in it; dogs who are tethered; unneutered male dogs; and multiple dogs.

Mistakes people make include reaching in to break up a dogfight, getting too close to a dog's face and letting dogs approach other dogs or people without first asking permission.

Even the nicest dog can bite if he feels threatened, but most bites are preventable with 10 reasonable precautions.

1. Teach dogs to wait for permission before approaching other animals or people.

2. Use a 4- to 6-foot leash instead of an extendible leash. It's too easy to let a dog get out of control, and the leashes can injure people as well.

"People get tangled in them, thrown off their feet and have had fingers torn off," Miller says.

3. Be alert to your surroundings so you know if other people or animals are approaching. You need to always be ready to either control your dog if he's reactive or get him out of harm's way if an aggressive dog approaches.

4. Teach children to ask permission before approaching any dog.

5. Take your dog to puppy kindergarten followed by obedience class. They are opportunities to work on training and socialization. Consider taking the class again so your dog gets more practice, especially if he is a large or active breed or mix.

6. Stay out of dog parks. They can be breeding grounds for canine bad behavior, such as bullying and aggression.

7. Pay attention to your own actions. Don't put your face close to a dog's face, especially if you don't know him or if he has been injured. That's just asking for a bite. The dog doesn't know you're trying to be friendly or to console him.

8. To separate fighting dogs, avoid the head, where the teeth are. Each owner should grab his dog's hind legs and pull the dogs away from each other.

"Don't let go," Miller says. "They will re-engage."

9. If you or your pet are bitten, clean the wound thoroughly and seek medical or veterinary attention. Report the bite to animal control.

10. Don't ignore or downplay aggressive behavior from your dog or someone else's dog, such as lunging, pulling on the leash or growling when he sees other people or animals. Nipping is a red flag, too. Dogs who get away with it become more ambitious and may graduate to more serious bites. Get help from a certified applied animal behaviorist or veterinary behaviorist.

Q&A

Itchy bunny may have

parasites, allergies

Q: My rabbit seems to really be scratching himself a lot and is starting to lose fur. What could be causing his itchiness? -- via Facebook

A: Skin problems aren't unusual in rabbits, and itching and hair loss are common signs. The "usual suspects" in these cases are parasites such as fleas, rabbit ear mites (Psoroptes cuniculi), Cheyletiella mites and mange mites (Sarcoptes scabei), or environmental allergies to bedding, chemicals used to clean cages or treat fabrics or other materials in the home, such as cedar wood shavings.

Your veterinarian is the only one who can make a diagnosis, and only after examining your rabbit. He or she may suspect ear mites if your rabbit is shaking his head frequently, scratching at the ears and head or has a thick, reddish-brown crust in the ears. If you notice this type of crustiness, don't try to remove it by cleaning the ears. That would put your bunny in a world of hurt. Your veterinarian will prescribe medication to kill the mites.

Rabbits can pick up fleas from dogs or cats in the home. If they live in an outdoor hutch, they may also be exposed to a different species of flea carried by wild rabbits in the area.

Cheyletiella and sarcoptic mange, caused by different types of mites, are diagnosed through skin scrapings that are examined microscopically for the presence of the mites.

Depending on the problem, your veterinarian will likely prescribe a topical or oral treatment, such as ivermectin, Revolution or Advantage. The medication and dose will need to be tailored to your rabbit, so don't assume it's OK to use the same product or amount you use on your dog or cat. Some products can be fatal to rabbits.

If an environmental allergy is suspected, try changing the bedding, washing the cage thoroughly to make sure all traces of cleansers are removed and switching to a scent-free detergent or fabric softener for any items the bunny comes in contact with. -- Dr. Marty Becker

Do you have a pet question? Send it to askpetconnection@gmail.com or visit Facebook.com/DrMartyBecker.

THE BUZZ

Cats beat dogs in

evolutionary race

-- Cats beat up dogs in the distant past, according to a study of 2,000 ancient fossils published in Proceedings of the National Academy of Sciences. More than 30 dog species were living the dream on the North American continent some 20 million years ago. Then cats arrived from Asia and started kicking dog tail, outcompeting canines for food with their awesome hunting skills.

"The arrival of cats to North America had a deadly impact on the diversity of the dog family," says the report's lead author, Dr. Daniele Silvestro, of Switzerland's University of Lausanne. Today, North America has only nine species of wild dog. No evidence shows that dogs wiped out any felid species.

-- Illinois becomes the latest state to protect pets from being left in cars in extreme weather conditions. With an amendment to The Humane Care for Animals Act, it becomes a misdemeanor to "expose the dog or cat in a manner that places the dog or cat in a life-threatening situation for a prolonged period of time in extreme heat or cold conditions that results in injury to or death of the animal." People convicted of violations face a fine of up to $2,500 or up to one year in jail. The legislation goes into effect on Jan. 1, 2016.

-- Is there a snake in your garden? Your first instinct might be to kill it, but snakes, even venomous ones, play an important role in the ecosystem. Len Ramirez of Auburn, California, travels the state humanely removing and relocating rattlers. To find a similar service in your area, contact animal control, a local herpetological association or your nearest university extension service for a recommendation, or do an Internet search for "humane snake removal" and let the experts handle it. They can also advise you on how to snake-proof your property so you won't have any more unwanted visits. -- Kim Campbell Thornton

ABOUT PET CONNECTION

Pet Connection is produced by a team of pet-care experts headed by "The Dr. Oz Show" veterinarian Dr. Marty Becker and award-winning journalist Kim Campbell Thornton. They are affiliated with Vetstreet.com and are the authors of many best-selling pet-care books. Joining them is dog trainer and behavior consultant Mikkel Becker. Dr. Becker can be found at Facebook.com/DrMartyBecker or on Twitter at DrMartyBecker. Kim Campbell Thornton is at Facebook.com/KimCampbellThornton and on Twitter at kkcthornton. Mikkel Becker is at Facebook.com/MikkelBecker and on Twitter at MikkelBecker.

CAPTIONS AND CREDITS

Caption 01: An estimated 4.5 million dog bites occur each year in the United States. Children and men are most likely to be bitten, according to the Centers for Disease Control and Prevention. Position: Main Story

Caption 02: Competition from cats played a more important role than climate change in the extinction of a number of ancient wild dog species. Position: Pet Buzz/Item 1