Giant Panda Bear
At one time, giant panda bears inhabited most of southern and eastern China, northern Myanmar, and northern Vietnam. However, over thousands of years, hunting, climatic changes, farming and land development have continuously declined their number and forced them higher into the mountains. Their habitat today has been reduced to the bamboo forests in 6 separate mountain ranges in central China at elevations of 4,000 to 13,000 feet. They claim smaller territories than most bears, usually between 1 and 3 square miles.
Male panda bears on average measure between between 5 feet and 6 feet long (nose to end of tail) and weigh between 175 and 275 pounds. They have been known to weigh up to 350 pounds. Females are about 20 percent smaller than males. Giant pandas have a very heavy fur coat consisting of a long coarse outer layer and an under layer which is dense and wooly. Like polar bears, their fur is very oily to repel water and protect them from the cool damp climate. Their torso and disproportionately large head are both white. They have black rounded ears, black eye patches, a black band across their shoulders, and black legs. Their front paws have extended wrist bones (radial sesamoids) which are flexible and can be used like a thumbs. This allows the bears to more skillfully handle their food such as bamboo stems.
The panda's eyes have pupils with vertical slits like many nocturnal animals and have excellent night vision. However, they are nearsighted and are thought to have limited color vision. They have extremely sharp senses of both hearing and smelling. Their molar teeth are larger than those of any other mammal which, along with strong jaw muscles, make it fairly easy for the giant pandas to crush bamboo. Both their esophagus and stomach have a tough lining to protect them from being injured by bamboo splinters.
Just like American black bears and Asiatic black bears, the giant panda bears have short claws and are excellent tree climbers. They are slow moving creatures and will speed up to a slow trot only if they feel they are in danger which is also one reason they climb trees.
Although giant pandas share ranges, they try to avoid one another and live very solitary lives except during mating season. They mark their territories using several scent glands which they have below their tails. They usually mark large objects such as ridges, boulders, or conifer trees.
Giant panda bears do not hibernate because they have a year-round supply of bamboo, and also because the bamboo, which their diet mainly consists of, does not supply them with a sufficient amount of fat to store for the winter. Instead of hibernating, giant pandas descend to lower elevations where it is warmer and they can continue to feed. The are most active in the early evening, though on occasion, they may be active throughout the day and night feeding.
Giant pandas have the digestive system of carnivores. However, over time they have adapted to a vegetarian diet and now feed almost entirely on bamboo. Over 99% of their diet consists of the leaves, stems and shoots of bamboo. Because bamboo is low in nutrients, they are forced to spend 12 to 16 hours a day eating 20 to 40 pounds of it in order to get an adequate amount of nutrition. Another reason why they must eat so much is that their carnivorous digestive system is capable of digesting only about 20 percent of the bamboo they eat. The giant panda will also on occasion feed on insects, small rodents, and fish.
Female giant pandas mature between 5 and 7 years of age. Mating season is from the middle of March to the middle of May. Females are in heat for anywhere from 2 days to 3 weeks, during which they often mate with several different males. Gestation period on average lasts about 135 days, but can range anywhere from 83 to 163 days. Like with other bears, there is a delay in the implantation of the embryo. The mother usually gives birth 2 cubs either in late August or September. At birth, the cubs weigh from 3.2 to 4.6 ounces and are about the size of a chipmunk. Regardless of however many cubs the mother may give birth to, she only attends to one. The others are left abandoned and soon die. It is believed that the second cub may be seen simply as insurance just in case the first cub isn't viable. The cubs are fully weaned by about 9 months and weigh about 75 pounds at one year. They usually remain with their mother for about 1.5 years.
It has been estimated in 2006 that there are more than 2,000 giant pandas in the wild, showing a recent increase in their population. However, some researchers claim that this apparent increase could be the result of a more detailed survey rather than an actual increase in the bear's number. Giant pandas in captivity have lived up to 35 years. However, their average lifespan in the wild is 15 to 20 years.