Queens vary in the age at which they first go into heat. Some breeds (such
as the Siamese) may have their first heat as early as 5 months. Others,
particularly the longhaired breeds such as Persians, are not sexually mature
until 10 months or older.
Cats are seasonally polyestrous. This means they will
have repeated heat cycles over a year unless they are bred, and the heat cycles
are influenced by the seasons. The mating season in cats is determined by a
number of factors, including the...
The short answer is scientists don't know. If you have allergies and want a cat, it may be possible to find one that won't bother you. But experts can't explain why.
Anatomy of an Allergy
People with cat allergies react to a protein in the animal's saliva, skin, and urine. The allergen collects on the cat's fur when the animal licks itself and comes off in tiny flakes of skin that glom onto walls, carpet, and furniture or stay in the air. A cat's lick or scratch can cause skin welts or itchiness. In the nose and lungs, the protein causes itchy, watery eyes and nasal congestion and can lead to asthma.
The allergens are so powerful that they can hang around for months, causing effects long after the cat is gone.
Some cats secrete less of the protein, some cats put out less saliva, and some cats produce less dander. But all cats make the allergen in some form -- and a tiny amount can cause a lot of symptoms, depending on how clean you keep your house and how often you're around the animal, says Robert Zuckerman, MD, an allergy and asthma specialist in Harrisburg, Pa.
"Even a cat that has a little bit of allergen can cause allergy if you have enough exposure to it," Zuckerman says.
The other variable is your immune system. Maeve O'Connor, MD, an allergy, asthma, and clinical immunologist in Charlotte, N.C., says one person can hold a cat and have no symptoms, while another has an asthma attack standing near a person with cat dander on his or her clothes.
Still, some allergy sufferers find their symptoms don't flare up around certain cats. Maybe they can tolerate domestic shorthairs but not oriental breeds -- or vice versa. Some can pet a white cat but start sneezing as soon as they touch a dark gray or black one. Many patients report they can only handle being around Siberian cats.
But research offers only clues, not answers.
"There are no scientifically validated studies to show that any particular breed of cat, whether it's Siberian or anything else, is 'hypoallergenic,'" says Martin Chapman, PhD. He's the president of Indoor Biotechnologies, an allergy testing company that provides the kits for most of the world's studies on allergen exposure.
Short of scientific proof, breeders have noted that Siberian cats seem less likely to trigger allergies.