Published: March 31, 2008 03:01 pm         

We’re just one of 5,000 mammals

What’s special about mammals?

Humans are among nearly 5,000 species of mammals, the class of the animal kingdom whose members have a remarkable ability to adapt to their environment. Mammals are warm blooded, enabling them to live over a greater variety of habitats than the other classes.

The smallest mammals (gray climbing mouse) weigh in at 1⁄4 ounce, compared to a seven-ton elephant (heaviest land mammal) or a 200-ton blue whale. All mammals are nursed by milk secreting mammary glands.

The earliest mammals arose about the same time as the first dinosaurs some 200 million years ago. But it was after the demise of the dinosaurs (65 million years ago) that mammals grew to prominence and exploded in variety.

In terms of their young, mammals can be divided into three groups: first, the monotremes or egg laying mammals, second the marsupials, whose very small young must cling to their mothers’ teats and be carried around for months and third, the placental mammals, whose young have developed considerably in the womb before birth. Even in this third category, the young must rely on their mother’s milk.

Of the mammals seen locally, the marsupials are represented by the Virginia opossums.

The local placental mammals have a number of different orders. The most numerous are the rodents, which make up 40 percent of all mammal species. Our local Eastern gray squirrels and Eastern chipmunks are rodents.

Now that spring has begun, rabbits (order of Lagomorpha) are out and about. Our local Eastern cottontail can weigh up to 3.5 pounds and feeds from late morning to evening.

The order of even-toed ungulates include our cattle, deer and pigs. The creatures of this order are usually ruminants. Their digestive system includes a rumen, a stomach where their food is fermented by bacteria, then regurgitated and chewed a second time. Complete digestion via this arrangement can take up to four days; this process allows the ruminants get more nutrition from their food.

The order of odd-toed ungulates includes our local horses. Digestion involves the cecum and large intestine. This two-day process is not as efficient as for ruminants. Odd-toed ungulates have to eat more food to get the same nutrition as their Even-toed cousins. (In contrast, the average transit time for human food is 32 hours.)

The most prominent local animals are of the order Carnivora, which include bears, cats, dogs, raccoons and skunks. Most bears are omnivorous (eat both meat and plants, just as humans). Bears have flattened carnassial teeth (used by cats and dogs to shred flesh), best suited for vegetation.

Cats are the supreme carnivores and hold the speed records for mammals. Our house cats come from feral cats domesticated by the Egyptians to kill mice feeding on human grain piles.

The dog family or Canidae includes, dogs, wolves, coyotes, jackals and foxes. Our domestic dogs (Canis familiaris) arose from wolves about 15,000 years ago who hung around human garbage dumps looking for scraps. Human controlled breeding in the last few centuries has given our dogs the widest range in size and form of any mammal species.

Raccoons are of the family Procyonidae, found only in the Americas. Raccoons’ omnivorous eating habits has allowed them to thrive both in the wilderness and in urban areas. Skunks are of the family Mustelid, nocturnal creatures, hence we usually smell them at night when they are on the prowl. Their family also includes badgers, ferrets, fishers, martens, minks, otters, weasels and wolverines.

In a future column, I’ll review the most exciting Mammal exhibits at the Frostburg State Exploratorium, which is open each Sunday at 5 p m. and 8 p.m. (through May 18) for free viewing.

April 2008 sky sights

This year, April is the best month to view the ringed planet Saturn through a telescope. For in the early evening, Saturn is high in the south, close to the bright star Regulus of Leo. To find Saturn, look for the Big Dipper high in the north and upside down, dumping its soup.

The leftmost stars of the Dipper’s scoop are the pointers; a line through the pointers going down will take you to the North Star. These same two stars point up towards Saturn and Regulus high in the south. Saturn is on the left and shining steadily while Regulus twinkles. A telescope magnifying 40X will show the rings of Saturn.

April is the last month to see some beautiful star clusters in the evening sky. (A star cluster is a concentration of stars that were formed together.) Low in the Northwest is the Pleiades or Seven Sisters star cluster, resembling to the eye a tangle of lightning bugs.

Farther to the left of the Pleiades is the Hyades, a looser star cluster, whose main stars form a sidewards V. To the right of Saturn and Regulus is the faint star group Cancer. If you take binoculars and look into Cancer, you’ll see a scattering of star dust, the Beehive star cluster.

Today will be the last planetarium showings of “The Ancients and the Sky” with free public showings at 4 p.m. and 7 p.m. Afterwards, planetarium visitors are invited to visit the FSU Exploratorium to see an awesome collection of preserved Mammals from five continents. The Planetarium is just off the front lobby of Tawes Hall.

Tawes Hall is near the FSU Clock Tower, the Lane Center, the Performing Arts Center and the Compton Science Center (where Exploratorium is located). To get a free Planetarium/Exploratorium bookmark and map, call (301) 687-7799 and leave your name and mailing address.

Bob Doyle invites reader’s comments and questions; email him at rdoyle@frostburg.edu .