The zoo's cold-weather mammals have turned white as snow


October 31, 1990|By Ellen Hawks | Ellen Hawks,Evening Sun Staff

LUXURIANT fur, long and very bushy tail, small ears, short legs, changes color with the seasons.

What else but the Arctic fox,which is brown in the summer and white in the winter.

It is the only fox, or wild dog, in the Arctic polar region and the only one that changes to two distinct colors. These pack-ice roamers turn white in the winter to minimize heat loss.

The four little 6-month-old Arctic foxes who are growing up at the Baltimore Zoo have also changed from brown to white over the summer.

But these foxes are in temperate weather and are well fed, cozy and having a ball. You'd think their thermostats weren't putting out the ''change color'' order. Not so. They have changed and authorities have no answers for why.

They were born in mid-May, and ''when they came to us in mid-July all of them were dark charcoal gray and brownish. As the summer went on, they began to get softer gray and slowly became white. At the moment they are as white as they'll get,'' says Sandy Kempske, curator of mammals who has been with the zoo for 11 years.

Early in May, she says, they will begin to turn gray again and will be dark by summer.

All four foxes, three females and one male, are from different breedings. ''We purchased them from a commercial Arctic fox ranch in Wisconsin where they are bred and sent to zoos and zoological institutions,'' she says.

It is impossible to tell them apart so they haven't been given names. A tiny tattoo in each one's ear is their identity.

Compared to our red fox here in Maryland, the Arctic fox is low to the ground, standing about one foot and weighing from 6 to 15 pounds. His feet are covered in thick coarse hair, and his coat is dense and soft.

In a group they do very well. ''Our male will probably choose one of the females, and she will be the only one he will mate. If that female becomes pregnant, she will be removed from the group for a period of time,'' says Kempske.

But if this fickle fox's choice female is removed from the group, he will probably chose another, notes Kempske.

The color change is by a molt twice a year and is interesting to watch. Kempske gives out a groan when asked about shedding. ''They really do shed. And as they become older some do not take good care of their grooming and, if that happens, we will have to comb ours. However, at the moment they are young, energetic and they are grooming each other,'' she says.

Come this spring, their luxuriant white hair will begin to thin and the long hairs on their flanks will go first. Then the undercoat comes out in hunks and a much thinner brownish and gray summer coat will begin to show. In the late summer and fall, another molt will take them to white again.

According to species information, the Arctic fox has the agility and inquisitiveness of a cat. When it was not wary of man, as it is today, it would enter the tents of Arctic explorers and take food and all manner of items such as equipment and clothing.

In its native habitat with the polar bear on the pack ice of the Arctic Ocean, the Arctic fox is farther north than any other land mammal. It is often called the blue or white fox.

In the wild it eats lemmings, rodents, dead whales, small birds, berries, eggs and the remains of polar bear kills. Like a squirrel it will store food in the summer for the winter, often killing much more than it needs.

At the zoo, the young foxes are eating a simple diet of canned Ken-L-Ration mixed with Purina high-protein dry food for dogs. ''It is a good balanced diet for them,'' says Kempske.

They are housed in the main valley, the older section of the zoo.

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