A genetic change known as the Himalayan gene has made this breed’s fur extra sensitive to temperature — but also leaves them easy to get certain diseases.
With 73 cat breeds recognized by the International Cat Association, it can be difficult to discern a Ragdoll from a Ragamuffin. Most of us, though, can pick out a Siamese cat. Known for their dark eye masks, nose, and tail — called “points” that stand out against their cream-colored bodies and sparkling blue eyes, the Siamese is one of the world’s easily recognized breeds.
Those trademark points stem from a genetic change known as the Himalayan gene, which was discovered in the breed in 2005. This hidden gene; passed down from both parents, also gives the felines (猫科动物) temperature-sensitive fur that can change color.
In the mother’s body, Siamese kittens develop at temperatures of about 101 Fahrenheit, a cat’s normal temperature. Once born, all-white kittens eventually begin to cool at their extremities (端点), such as their tail, legs, ears , and face. These lower temperatures cause the Himalayan gene to activate the body’s melanin (黑色素), also found in people. That’s why a Siamese cat’s warmer bodies stay light, but their cooler parts become darker as they mature.
“You can see them change,” says Betsy Arnold, a vet who runs a cats-only practice in Rochester, New York, and started breeding Siamese when she was in her teens.
At about two weeks old, Arnold says, dark color begins to spread to their limbs. By about a month old, their final color emerges, which may be one of several varieties, among them blue point, lilac point, chocolate point, and seal point, which has a light, cream-colored coat with dark brown color on its paws, tail, nose, and ears.
8. What may the underlined part in paragraph 2 mean?
A.Take care of those sick cats. | B.Tell the difference between them. |
C.Take them back to the rescuer center. | D.Evaluate their health conditions. |
9. Why is a Siamese cat easy to recognize from others?
A.It stands out against other cream-colored cats. | B.Its fur is sensitive to the temperature outside. |
C.It has a genetic change — the Himalayan gene. | D.Its extremities are all dark-colored with blue eyes. |
10. What can we infer from the last paragraph?
A.The color change of a Siamese is a gradual process. | B.An elderly Siamese can change its color. |
C.A Siamese can only change its color to black. | D.Siamese cats are sensitive to climate change. |
11. What might be the best title for the article?
A.How Siamese Cats Change Their Colors | B.How a Mysterious Gene was Found in Nature |
C.What Scientists Found in Himalaya | D.Why a Siamese Cat Looks Strange |