Monday, July 19, 2010

Apple #472: Bears by Size

I went to the zoo last weekend with a friend.  We saw polar bears, black bears, brown bears.  This raised the question, which type of bear is the largest?  Is it really the polar bear, as the exhibit claimed?  What about the Kodiak bear?  Time for the Apple Lady to get to work.

In looking for facts about each species, I found some facts that seemed to be common among most of them.  Bears are mainly huge and strong, but they're also smarter and more capable than I think most of us today typically give them credit for.  Here are some of those common traits:
  • Bears are not nearsighted, as is commonly believed.  Their vision is actually quite good.
  • They have extraordinarily keen sense of smell, often able to smell food from miles away, even canned food.
  • They have excellent long-term memories and their navigation abilities exceed those of humans.
  • Most bears are good swimmers. Some can swim half a mile or farther in fresh water.
  • Many can run as fast as 30 mph.  Imagine a 500-pound animal running at you at 30 miles an hour!
Here's the list of bears in order of size, from biggest to smallest:
  1. Polar bear
  2. Kodiak bear
  3. Grizzly bear (type of brown bear)
  4. Black bear
  5. Giant panda
  6. Sun bear
  7. Sloth bear
Now here are the details about each, including dimensions, species name, and a few facts about what they eat and their habits.

Polar bear
Ursus maritimus

This polar bear has collapsed from heat exhaustion. Not a happy sight, but I chose this photo to give you a sense of the bear's size.
(Photo from Eco-Enquirer)


nose-to-tail length: 7 to 8.4 ft.
shoulder height: 5.3 ft. (that's as tall as me)
avg weight: 900 to 1,600 lbs
Polar bears are the largest land predators alive in the world today.


Range, in yellow, of the polar bear
(Map by National Geographic)

  • There are about 25,000 to 40,000 polar bears in the world.
  • Their paws have several features which help them in their environment:
      • slightly webbed, which helps them swim better,
      • furry even on the underside for greater protection against the cold ice
      • wide and flat, which makes them act like snowshoes
      • that shape also helps them literally shovel snow to build their dens
      • are covered with small papillae -- miniature cleats -- and indentations -- mini suction cups -- both of which help increase friction and stability on the ice
  • Forepaws are 5-3/4 in long and 9 in wide (fatter than they are long). Hind paws are 13 in long and 9 in wide.
  • Their fur is white, which provides camouflage. 
  • Their skin beneath is black, to help absorb heat from the sun.
  • Mature males' fur turns yellow as they age.
  • When polar bears dive into the water, their ear canals close in protection against the frigid water.
  • Seals are their main food source. Polar bears sit by cracks or holes in the ice. When seals surface to breathe, the polar bears lunge its head forward and grab the seal in its mouth.
  • A polar bear will eat a seal once every 5-6 days.  Their stomachs can store 150 lbs of food. 
  • Polar bears can smell seals up to 40 miles away. 
  • They also eat grasses, seaweed, berries, lemmings, and voles.
  • They may also hunt beluga whales and walruses.
  • Females dig their dens into deep snow drifts.
  • 2/3 of all polar bear births are twins.
  • Polar bears have no natural enemies except humans.

A couple naturalists observed a polar bear and a husky dog becoming friends and playing with each other.
(More photos at Session Magazine)

video
Polar bear swimming. She's using her front paws almost exclusively. 


Kodiak Bear
Ursus arctos middendorffi

The massive shoulder hump on the Kodiak is obvious here.
(Photo from the North American Bear Center)

nose-to-tail length: up to 10.5 ft
shoulder height: 5 ft
avg weight: up to 1,500 lbs
The largest Kodiak in captivity was Clyde, who lived in the Dakota Zoo in N.D.  When he died at age 22, he weighed 2,400 lbs.


The green spot is the Kodiak Archipelago, the only place on earth where Kodiak bears live.
(Map from Alaska Department of Fish & Game)

  • Kodiaks are a subspecies of the Brown bear
  • They live only on the Kodiak Archipelago in Alaska
  • Only about 3,000 Kodiaks are alive today
  • They have a large shoulder hump, which is a mass of muscle, that helps them dig for food
  • They eat 90 lbs of food a day, most of it plants and berries.
  • Also eat salmon, deer, elk, or cattle.
  • They are usually solitary, but they often feed in large groups. To make sure everyone gets enough to eat without fighting, they have developed their own unique language and social structure.


Bart the Bear, a Kodiak bear actor, who lived 22 years. This photo gives you a good idea of this bear's size.
(Photo from Bart the Bear's unofficial home page)


Brown Bear / Grizzly Bear
Ursos arctos / Ursus arctos horribilis

The grizzly bear's white-tipped fur, shoulder hump, and long snout are its easily distinguishable traits.
(Photo from the USGS)

nose-to-tail length: 6 to 7 ft
shoulder height: 3 to 3 1/2 ft
weight: coastal, up to 1500 lbs
weight: inland, up to 850 lbs
avg weight: 550 lbs



Range, in orange, of the Grizzly or brown bear
(Map from Defenders of Wildlife)

  • In coastal Alaska and Canada, they are called Brown bears.
  • In the inland 48 states, they are called Grizzly bears
  • Around 1,000 - 1,200 grizzlies in the lower 48, around 30,000 in Alaska.
  • Has a hump on its shoulders and long, straight claws
  • Outer, long hairs called "guard hairs" on back often have white tips, giving them a "grizzled" appearance
  • Brown bears' fur may range in color from dark brown to light blond.
  • Grizzly bears like vegetation and will eat grasses, roots, berries, mushrooms.
  • Coastal brown bears eat salmon but a lot more vegetation than grizzlies.

I saw this brown bear at the zoo.  He's tearing into a stump to get at the bugs in it. He had just gotten out of the water, where he'd been scooping up seaweed from the bottom of the pool with his claws and eating it by the pawful.
(Photo by the Apple Lady)

  • Inland grizzlies eat moose, caribou, or elk, or small mammals, as well as vegetation. 
  • 70% of human deaths from grizzlies were by a female defending her cubs.
  • In the lower 48, grizzlies are Endangered, except for those who live in Yellowstone.
  • In Alaska, they are a game animal and may be hunted but according to very strict regulations.

Grizzly bear's paw. Man, that's big.
(Photo from Frances Hunter's American Heroes Blog)


Black bear
Ursus americanus

A black bear from Tennessee
(Photo from First People)

nose-to-tail length: 4 to 7 ft
shoulder height: 2 to 3 ft.
avg weight: 200 lbs to 600 lbs


Range, in yellow, of the black bear
(Map from National Geographic)
 
  • May be black, blue-gray, blue-black, whitish-blue, brown, cinnamon, blonde, or even white
  • Eat plants, fruits, nuts, berries, bugs, honey. Also salmon, small mammals, and carrion.
  • About 600,000 black bears in North America, about half in the US.
  • Their eyes are blue when they're born but turn brown as they mature.
  • Black bears have never been known to attack a human. In fact, all adult black bear deaths are human-related.
  • There are 16 subspecies of black bears, mostly distinguished according to where they live.
  • The Cinnamon Bear, Kermode Bear, and Glacier Bear are all subspecies of black bear.
  • Louisiana black bear and Florida black bear are threatened subspecies.

The Kermode Bear, in the foreground, is a white subspecies of the black bear. You can tell it's not a polar bear by the shape of the head, which is much more round than a polar bear's wedge-shaped skull.
(Photo from UniqueDaily)


[edit:] Eagle-eyed regular reader Jason alerted me to this news article about a bear -- a black bear, I think -- that broke into one family's Toyota, accidentally shut itself inside, knocked the car into neutral, and rolled downhill. Really funny and worth a look.


Giant Panda
Ailuropoda melanoluca

Giant panda, doing its favorite thing: eating bamboo
(Photo from Scientific American)

nose-to-tail length: 5 1/2 to 6 ft
shoulder height: 2 to 3 ft
weight: 200 to 330 lbs.


Giant pandas live in only six small bits of forests in mountain provinces of China -- those little red dots.
(Map from the San Diego Zoo)

  • Naturalists weren't sure for a long time whether pandas were more like raccoons or bears. Finally they decided that pandas were a type of bear. But they remain classified separately from all other types of bears.
  • Only about 1,000 to 2,000 giant pandas exist in the world.
  • Eat bamboo almost exclusively, 10 to 12 hours each day.
  • Have large crushing molars, large jaws, and an exceptionally wide esophagus, all the better to eat and swallow the bamboo.
  • Because they can't build up enough fat on their bamboo diet, they don't hibernate in winter but instead migrate to warmer climates.
  • Panda bears were the second animal after dogs to have their genome decoded by scientists.  They discovered, among other things, that pandas can't taste umami, that mysterious and complex sixth taste. So researchers think that meat simply doesn't taste good to pandas, and that this may explain why they prefer bamboo.
  • Unlike many other bears, they're not quick movers, but if necessary, they will catch small animals for food.
  • Have an enlarged wrist bone which is functionally a sixth digit that pandas use similarly to a thumb.
  • They don't roar like other bears but make a bleating sound like a goat.


Sun Bear
Helarctos malayanus

The Malayan Sun Bear showing off its claws and its telltale yellow-orange chest patch.
(Photo from the Wellington Zoo)

nose-to-tail length: 4 to 5 ft
avg weight: 60 to 150 lbs.


Range, in yellow, of the Sun Bear
(Map from National Geographic)

  • Named for the lighter-colored bib-shaped patch on their chests, which were said to resemble the rising sun.
  • Sometimes also called the honey bear.
  • Unlike most other bears which are active during the day, sun bears are nocturnal.
  • They are very shy and live in remote areas, so not much is known about them.
  • They are omnivores, but the fruits they like are coconuts, palm trees, and bananas. 
  • They also eat small birds, lizards, and rodents.
  • Sun bear mothers have been observed cradling and carrying their young in their arms while walking on their hind legs.


Spectacled Bear
Temarctos ornatus

Some spectacled bears have markings that go all the way around their eyes, like this one. But not all of them do.
(Photo from Zoos Worldwide)

nose-to-tail length: 5 to 6 ft.
avg weight: 220 to 340 lbs.


Range, in yellow, of the Spectacled bear
(Map from National Geographic)

  • Markings on the spectacled bear are unique to each bear, like a fingerprint.
  • Sometimes called the Short-Faced bear or the Andean bear.
  • The only bears that live in South America, they live in the jungles in the Andes Mountains.
  • Mostly nocturnal, solitary except during mating season, and very shy.
  • Eat vegetation including tree bark and orchid bulbs, fruit, berries, cacti, honey. 
  • May also eat meat such as rodents, small birds, insects, and small cows.
  • They have been known to climb trees, break off branches to make a platform, and sit there waiting for several days for fruit to ripen.

Another spectacled bear, with fairly different markings
(Photo from the Phoenix Zoo)


Sloth Bear
Melursus ursinus

The sloth bear has shaggy fur which reminds me of a dog's.
(Photo from Bears of the World)

nose-to-tail length: up to 6 ft
avg weight: 120 to 310 lbs.


Range, in yellow, of the Sloth Bear
(Map from National Geographic)

  • Have a shaggy black coat, and a cream-colored snout and bib on their chest.
  • Eat mainly termites and ants. They will use their claws to dig open rock-hard insect mounds, blow away the excess dirt, and suck up the insects through a gap in their front teeth.
  • Also eat mangoes, figs, flowers, and sometimes honey.
  • These bears are also sometimes called honey bears.
  • There are 2 subspecies, the Indian and the Sri Lankan.
  • The only bears to carry their young on their backs.

Sloth bears going after a termite mound in the London zoo.
(Photo from the London Zoo)


Other "bears" that are not bears
  • The koala is not a bear but a marsupial.
  • The red panda is not a bear but its own species, more closely related to the raccoon.


Sources
Alaska Department of Fish & Game, Brown Bear, Kodiak Bear Fact Sheet
Kodiakbear.net, Kodiak Bear Facts 
Defenders of Wildlife, Grizzly Bear, Black Bear
Great Bear Foundation, Brown Bear, Panda Bear (giant panda)
National Geographic, Grizzly Bear, Black Bear, Sun Bear, Polar Bear, Sloth Bear
North American Bear Center, Quick Black Bear Facts, Polar Bear Facts
Pandabearmd, Panda Bear Facts
San Diego Zoo, Mammals: Giant Panda, Mammals: Andean (Spectacled) Bear
Katherine Harmon, Giant panda genome sequenced, explains taste for bamboo, Scientific American, December 13, 2009

7 comments:

  1. fork stealer7/21/2010 12:27 AM

    I can't believe you left out the Pooh Bear!

    ReplyDelete
  2. Wonderful post! The extent of your research never ceases to amaze me. www.satisfiedsole.com

    ReplyDelete
  3. Very enlightening post, especially for those interested in bears. Well done!

    ReplyDelete
  4. Excellent post about bear sizes! I've learned so much from this post. Thank you!

    ReplyDelete
  5. very nice post. just what i needed.

    thanks!

    ReplyDelete
  6. Thank you! Very nice pictures and good information on bears. I've heard of black bears reaching 800 lbs where I lived on Purdue Mountain in Centre County, Pennsylvania.

    ReplyDelete
  7. Oops, this is decidedly not true --> "Black bears have never been known to attack a human. In fact, all adult black bear deaths are human-related."

    While the latter statement true true, black bears *will* attack a human particularly in areas where they have become habituated and think of humans as easy sources of food.

    The good news is that black bears are not as ferocious as brown/grizzly bears, so injuries from black bears tend to be less severe.

    See http://ext.nrs.wsu.edu/publications/Blackbears1.htm for a good brief summary.

    ReplyDelete

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