Friday, February 1, 2013

Science Week 17: Great Bears of the Forest and Ice Floes

Except for opossum babies, no other mammal infants are as tiny in comparison to their mother as the bear infants. Born during the mother's winter hibernation, they may weigh as little as 1/200th of her weight. In the dark, cold den, the small rat-sized cubs are nearly lost in the dense fur of their mother. Hairless and blind, they snuggle contentedly into the shaggy folds of the mothers abdomen, where hidden milk glands allow for warm, comfortable nursing.

photo credit: Drive to Nature blog

Bears are mostly created for forest and mountain regions. In the spring bears graze like cattle on the new tender shoots and grasses. Later in the season, they use their strong shoulders, and powerful claws, to rip open rotting logs to lick up ants, beetle grubs, termites, and many other insects. Digging into ground burrows, they find chipmunks, marmots, moles, mice, ground squirrels, and lemmings. Crickets, grasshoppers, birds and their legs, snakes, frogs and toads, acorns, fruits, and wild honey, keep these big mammals well nourished.

Black Bear
photo credit: Bears of The World

The black bear is the smallest and most common of the American bears, and like other bears, it travels alone except for when still being cared for by its mother as a young cub. The same trails through forests and thickets will be followed for 50 years or more. Along these trails, bears will stand on their hind legs and rub their backs against the bark of trees. They bite it until it shreds loose in places, where pitch oozes out and sticks their hair to the trees. The next bear on the trail will do the same thing, leaving his scent behind for the next trail walker.


Grizzly Bear

Next in size to the widespread black bear is the grizzly. Originally found in the western part of North America, from Alaska to central Mexico, and east to Minnesota, there are now very few south of the Canadian border except in protected wildlife park areas.


The grizzly's diet is roughly 80-90% vegetation, though they come down to meet the salmon that run up-river from the sea. As the salmon swim up-river, the bear will knock it out of the water with a blow from its paw. When injured or attacked, the grizzly will react fearlessly.  It can run as fast as a horse, and a blow from its paw will crush or break the bones of even a huge bison.

Grizzly Bears, Bears of the World

File:Bear Square.JPG
photo credit: Wikipedia

The brown bear, also known as The Alaskan Brown Bear or Kodiak Bear is the largest of all bear species. Like the grizzly, it has its own set of trails along the rivers of British Columbia and southern Alaska. As the salmon swim up the river by the thousands, the big brown bears have a feast. After spawning, the salmon die and float down-stream, sooner or later coming to rest against a rock or sandbar. The great bears enjoy eating carrion, so the smelly dead heaps of fish are quickly removed and the riversides become clean in short order.

Brown Bears, Bears of the World
Brown bears, Alaska Dept. of Fish & Game be sure to check all the tabs below the article for more information

Brown bears are larger than black bears with male grizzly bears standing about 7 feet tall and generally weighing from 200 to 600 pounds. There have been some male bears that have weighed more than 800 pounds. Females are smaller, usually weighing between 200 and 400 pounds. Generally remaining on all fours, when a grizzly does stand, it is commonly perceived to be a threatening pose however they are just simply curious or surveying their surroundings.
Despite being categorized as ‘black bears' and ‘brown bears' to make a distinction, color is never an indicator of species. Both black and brown bears can range from almost white to blonde to pure black and many color phases in between depending on age, sex and season.
The main differences between the black bear and brown bear, is that the brown bear has a rather concave face, high-humped shoulders, and long, curved claws. The grizzly's thick fur, which varies from light brown to nearly black, sometimes looks frosty-looking, hence the name "grizzly," or the less common "silvertip."
Furthermore, the grizzly has more rounded shorter ears. Nevertheless, you cannot pin point one characteristic to distinguish between a grizzly and black bear, it is a combination of characteristics that will help you identify the bear specifically. Each may have a similar-colored coat, a less-than-concave face and small or large shoulder humps.
~~via Brown bear.org




File:Polar Bear - Alaska.jpg
photo credit: Wikipedia

The polar bear is the monarch of the arctic ice pack. On snow covered floes, these great bears will drift for hundreds of miles in the Arctic ocean, the Atlantic ocean, or through the Bering Strait into the Bearing Sea. They may swim 15-20 miles out to an iceberg in search of their most important food source, seals. When the seals are scarce, they will live on carrion. A sudden freeze may strand a white whale or a narwhal inside a little bay that later becomes so small the creature cannot breath adequately. A polar bear may kill even a whale that is 15 feet long. The powerful carnivore is able to drag an 800-pound animal out onto the ice. A large dead whale will provide food for bears, arctic foxes, gulls, and ravens all winter.
Fast Facts
  • Size
  • Males: 600–1200 lbs. 8–10 ft.; Females: 400–700 lbs.
  • Lifespan
  • 25 years
  • Distribution/Range
  • Circumpolar, northern hemisphere only
  • Diet
  • Ringed seals, bearded seals, walruses, beluga whales
  • Predators
  • Male polar bears, and Alaska Native hunters
  • Reproduction
  • 2 cubs once every 3 years


Bears lapbook, Homeschool Share, another one here, heared toward Preschool-1st
Polar Animals lapbook, Homeschool Share
Polar Bear Squidoo Lens
Polar Bear lapbook at The Schroeder Page blog
Polar Bears, Early and Modern at Bears of The World

Bears like to clown around and play like most animals. A polar bear will rock themselves on a drifting ice floe or slide down a slanting, slippery glacier side. They have been seen walking along a narrow wall of ice with an almost vertical glacier below, then jump onto the slick surface of the glacier and whiz itself down, without trying to slow themselves down, until they reach the edge of the glacier. There, with a sheer 50 ft drop, they will sail into the air and plunge into the water below. Sometimes they will sit near an icy slope and, just as you or I would, rock themselves back and forth to get started sliding downward. 

bear track account, Wilderness College







Monday, January 28, 2013

Science Week 16:The Weasel Family, Rich Fur and Musk Bags

Finally, right? Life in a large family on a wide, rural, animal-filled homestead isn't always conducive to proper scheduling I guess.

Can you believe some folks simply don't SEE God in nature around them? Everything has been designed with such order, and yet it still eludes so many people as to the fact it actually has been planned out, designed for a purpose.

God has, in His Divine Wisdom, placed trees, reptiles, birds, fishes, mammals and such into groups together, into habitats where each depends on the other to varying degrees for food, for shelter, for life. Too often, man determines that this Plan is wrong, and starts to take matters of design into his own hands, redesigning the habitats of all around him. Man decides one day that he alone, being a higher creature, has the right to be a predator. The predatory animals, he determines, are greedy and blood-thirsty. He alone should have the free reign to hunt other animals. So he sets about to put his own plan into motion.

In 1906 the Grand Canyon National Game Preserve in Arizona sheltered 4000 deer. State Game officials determined that many more deer could, and would, live in this area if predators were removed.  They closed all deer hunting for a time. Then they instituted a paid hunt program in which men were paid a designated price for each large predatory animal killed. Records show that up until 1924, 4889 coyotes, 781 cougars, 30 wolves, and 554 bobcats had been destroyed because of this paid hunt program. In 1916, 30,000 deer were living in the protection of the forest. Two years later, 40,000 were roaming the game preserve, and by 1924 there were close to 100,000. The plan to increase the deer population, and decrease the predator population was a success...right?

Because of the increase in deer, young saplings and new shoots were devoured, larger trees died as hungry deer chewed off bark and dug up roots in effort to stay alive.  Erosion of the bare slopes began. In truth, the whole of the countryside looked as though it had been devoured by a swarm of locusts. Over 40,000 deer died from starvation and disease during the next 2 winters. Tens of thousands died until the herds of deer numbered only 10.000, and many of these were quite small and weak. Even with just 10,000 deer on the acreage, the food supplies remained scarce. Other populations suffered as well. The cougars, wolves, coyotes, and bobcats had not only prospered the deer, they had also protected the vegetation and trees the other animals were dependent on.

God's Wisdom created groups of animals and placed them together into habitats to be useful, even beneficial, to one another. Mans efforts to reorder the Master Design all too often appear to be working, but in time prove to be failures, often to the point of extinction of certain animal and vegetation.

Carnivores, or meat eaters: the smallest of these studied so far has been the kit fox, that weigh in at only 4-6 lbs. The weasel, tiniest of all, weighs less than an ounce. Long and slender in body, round ears, short legs...
weasel
photo credit: Chris Beever

Weasels are known for the beauty and softness of their brown fur, and for the little bags of musk carried in glands under their tails.  Weasels living in the north lands turn white almost overnight when the first snow falls. Brown hair is shed and white grows in its place. This snowy plush fur is known as ermine. In Europe weasels are called stoats. Their pelts often trim very showy clothing.

Weasels move quickly, and continually. Heartbeat, breathing, and digestion are fast and much food is needed to sustain them. Dogs and cats may maul, or play, with their prey, but weasels are hungry all the time. They kill their food at once. Weasels may store piles of dead mice in their burrows or under leaf litter. Shrews, moles, and nesting birds are also taken. White-footed mice and meadow voles (nice PDF here) make up 50-80% of the weasel's diet. 

The Slinky, Stinky Weasel Family, from The Young Naturalists check out the sidebar for some great printable teaching resources too.
Weasels, from ThinkQuest


Skunks
photo credit: Free-Extras

The most common and well-known member of the predator weasel family is the skunk.  There are 6 species of skunk found in the United States, Mexico, and Canada: eastern spotted, western spotted, hog-nosed, eastern hog-nosed, hooded skunk, and the striped skunk. The fur of these creatures, both natural and dyed, are highly sought after.

Skunks eat hoards of crickets, grasshoppers, and beetles. These slow animals den under sheds and barns, finishing off their mouse populations. In New York State, the skunk is protected for the sake of the hop crop that is eaten by a grub that the skunk likes to feed on. All in all, skunks are said to destroy more insects than all other kinds of mammals combined.

All skunks carry the bags of musk common to weasels.  However, they have spraying muscles that other weasels don't have.
Skunk Spray, a chemical called N-butlymercaptan, is a volatile mix of sulfur-containing compounds. The skunk produces and stores these chemicals in a pair of glands on the lateral sides of its anus. It stores enough for roughly 5 sprays, and it will need more than a week to produce more. The spray can reach almost 15 ft with impressive accuracy. The victim will not only succumb to the smell, but may also xperience temporary eye irritation or blindness. It is an effective defense that keeps all but a few sneaky predators away.
skunk printable, Enchanted Learning
Handbook of Nature Study Outdoor Hour Challenges #12 and #50

photo credit: The Independent

The low, wide, powerful clawed badger is among the best digging mammal in the United States. Underground, in burrows, the badger has the ability to catch any creature it smells because it can dig faster than any other animal can. Badgers dig complicated burrows with sleeping and eating rooms where carrion is often stored. Several generations of badgers may live in the same maze of tunnels as long as food is plentiful. The mothers care for the young, while the fathers do not usually stay with the families. Like skunks, badgers grow fat in the autumn, but they do not hibernate, although they will sleep for extended periods of time during the winter.  They have grown more scarce than they once were due to their main food source, prairie dogs, being decreased in population. Eagles or coyotes carry off young and small badgers, and larger predators, such as cougars or wolves, sometimes succeed in killing full-grown badgers. 

American Badger, Nature Works
Badger printable, Enchanted Learning


Wolverine

The wolverine is the largest of the weasel family. In disposition, it is more like the weasel than the skunk or the badger. They may roam over 100 miles in search of food sources. They look like a small, chunky bear, and their muck glands carry scent as powerful as that of the skunk. In fact, their nickname is skunk bear.

Once, a group of men on Mount McKinley in Alaska, discovered where a wolverine had killed a Dall's sheep, weighing about 150 lbs,  and had carried the sheep a mile and a half, down the mountain and across a river, before climbing a steep bank with it and beginning to eat it.  Not only is the wolverine known for its unusual strength, it is also very fast and can easily run down a moose, deer, or hares.  When chased by wolves, it can easily leave them far behind.  It is also a strong swimmer and can cross lakes and rivers to search for or follow food. It is also a skilled climber. Sometimes wolverines retreat before bears or packs of wolves come, other times they will remain and fight without fear, chasing off cougars, bears, wolves, or coyotes from food they want for themselves.

Wolverines, like others in the mustelid family, have valuable fur.  Moisture will not freeze on wolverine fur, and it is usually cut into large strips and used to line the opening of parka hoods.  Arctic travelers have always preferred wolverine fur for this reason. Skiing and winter sports created a larger demand for the wolverine-lined hoods as well.

Wolverine Fact Sheet, Defenders of Wildlife
Endangered Species: Wolverines U.S. Fish & Wildlife Services






Friday, November 23, 2012

a Science Week break thru the New Year

I know we have skipped yet another week, but with Thanksgiving preps and crafting projects, we are working a jumbled schedule around here. I expect this to be true for the majority of December as well, so if you are following along, please plan to catch-up or resume the weeks with us after the New Year.

When we resume, we will learn about:
the fur-bearers and musk gland group
Bears, the kings of the forest lands
whales, dolphins, porpoises and manatees
fin-foots and kelp-dwellers (seals, walruses, and sea otters)
the burrowing life of shrews, moles, pocket gophers, chipmunks, ground squirrels, prairie dogs, marmots and armadillos)
Leafy Treetop dwellers (red tree mouse/red tree heather vole, pinon mouse, golden mouse, southern flying squirrel, red squirrel, gray squirrel, fox squirrel, marten, the fisher)
mammals of the flowing water (northern water shrew, mink, chocolate cottontail, marsh rabbit, muskrat, coypu, river otter, beaver)
desert dwellers (pocket mouse, kangaroo mouse, ord kangaroo rat, collared peccary)
mammals of the barren ground and polar seas (lemmings, arctic ground squirrels, arctic fox, ringed seal, narwhals, white whales, bowheads, musk ox)

We'll see you back here for Science Week lessons beginning on January 7th.