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Name: Richard
Status: Student
Grade: 6-8
Date: 2/7/2005 

Why dose my dog loses a lotof hair every season?

Hi Richard,

You are very observant to notice that dogs shed more hair during certain times of the year. In areas where there is less temperature change (like California), and for pets that live indoors and are exposed to lightbulbs rather than sunlight, the change in coats between seasons is often less noticable. Changes in hair coat are often seen more for wild animals. In fact, some animals, like artic fox, grow hair of one color in the winter and of a different color for the summer.

For most animals, the winter coat has lots more soft, short, warm fur that forms an insulating undercoat. Many of these hairs are shed in the spring. The summer coat has fewer hairs, and the hairs are also longer and thinner. This is much cooler for the animal in summer.

Animals (and humans) grow and shed hair at a slower rate year-round. For many animals, changes in the amount of sunlight, in the spring and fall, cause the brain to send a signal to the base of the hairs where growth occurs. Some of the hair stops growing and are shed. More of the short undercoat hairs grow in the fall and less in the spring.

Keep thinking great "why" questions about science!

Laura L. Hungerford, DVM, MPH, PhD
Associate Professor and Interim Head
Division of Foodborne and Emerging Pathogens
Department of Epidemiology and Preventive Medicine
University of Maryland School of Medicine

Hi Richard!

If the hair loss is too great at every season (that means it looses all the time?) it could be some particular condition and you must look for a vet. But it is normal for furries to loose hair and mostly at a season or another.In winter they usually keep the fur, nature protection.

It depends also upon the animal race.Long hairĀ“s as Poodle looses a lot, for ex. We loose hair also, our hair grow and the new ones replace the old ones. Again if it is too much, like having patches of bald skin, could be some problem with the food, lacking some element or again some parasite or infection.

Thanks for asking NEWTON!

(Dr. Mabel Rodrigues)
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