Adult giant pandas may be generally solitary, but they do communicate periodically through scent marks, calls and occasional meetings. Recent research has also found that giant pandas may form communities of seven to 15 individuals within the local population. These individuals occupy a "group" territory, within which male home ranges overlap almost completely, while female home ranges overlap far less. Members of different "groups" generally avoid socializing with each other. Offspring stay with their mothers from one and a half to three years.
Giant pandas reach breeding maturity between four and eight years of age. They may be reproductive until about age Female pandas ovulate only once a year, in the spring. A short period of two to three days around ovulation is the only time a giant panda is able to conceive. Calls and scents draw males and females to each other. Female giant pandas give birth from 90 to days after mating. Although females may give birth to two young, usually only one survives.
Giant panda cubs may stay with their mothers for up to three years before striking out on their own. This means that a wild female, at best, can produce young only every other year. In a lifetime, a giant panda may successfully raise only five to eight cubs. The giant pandas' naturally slow breeding rate prevents a population from recovering quickly from illegal hunting, habitat loss and other human-related causes of mortality.
At birth, a giant panda cub is helpless, and it takes considerable effort on the mother's part to raise it. A newborn cub weighs ounces and is about the size of a stick of butter.
Except for a marsupial, such as a kangaroo or opossum, a giant panda baby is the smallest mammal newborn relative to its mother's size. Cubs do not open their eyes until they are weeks old and are not mobile until they are 3 months old. A cub may nurse for eight to nine months and is nutritionally weaned at 1 year old, but not socially weaned for up to two years.
In the wild, giant pandas typically nap between feedings for two to four hours at a time, snoozing on their side, back, or belly, either sprawled or curled up. While a giant panda is resting, it continues to defecate. The number of droppings at a rest site can be used to gauge the relative amount of time a giant panda spent at that site.
During a short rest of less than two hours, there are five to ten droppings. Eleven to 25 droppings often accompany rests lasting longer than two hours.
Most rest periods are two to four hours in duration but may increase to six or more hours during the summer months. Scientists are not sure how long giant pandas live in the wild, but they are sure it is shorter than lifespans in zoos.
They estimate that lifespan is about years for wild pandas and about 30 years for those in human care. Chinese scientists have reported zoo pandas as old as The largest threat to giant panda survival is habitat destruction. People in need of food and income have cleared forests for agriculture and timber.
This logging has fragmented a once continuous habitat, leaving small groups of pandas isolated from each other. When populations become small, they are extremely susceptible to extinction due to environmental or genetic influences, such as drought or inbreeding. Small populations cannot rebound the same way large populations do; as groups of pandas become more isolated, it is more likely that reproduction, disease resistance and population stability will be threatened.
For more than 40 years, the Zoo has celebrated these charismatic bears by creating and maintaining one of the world's foremost panda conservation programs. In that time, the Zoo's team — consisting of dozens of animal care staff, scientists, researchers, international collaborators and conservationists — has made great strides in saving this species from extinction by studying giant panda behavior, health, habitat and reproduction. Specifically, it has allowed scientists at the Smithsonian's National Zoo and Conservation Biology Institute to learn about panda estrus, breeding, pregnancy, pseudopregnancy and cub development — work that is shared around the world with other institutions that also care for and breed this vulnerable species.
See a history and timeline of giant pandas at the Zoo here. Much has been learned since that time, but there still remains much more to learn. With the arrival of Tian Tian and Mei Xiang, the Zoo has developed a ten-year research plan that will hopefully culminate in a growing, thriving population of giant pandas. Some research areas will repeat behavioral observation studies on Tian Tian and Mei Xiang in order to increase sample size and determine whether a behavior pattern is common to giant pandas or particular to an individual.
In other areas, such as reproductive biology, the advanced techniques scientists use today largely did not exist when Ling-Ling and Hsing-Hsing were alive. Also, opportunities for research and conservation initiatives in the wild, including the potential for increasing the wild giant panda population in China through reintroduction, are greater today than at any time in the past.
However, these plans and initiatives will be costly to carry out, as will China's official National Plan for the Conservation of Giant Pandas and their Habitats. Scientists from the Smithsonian Conservation and Biology Institute's Center for Conservation Genomics, have become adept at studying the genetic relatedness of pandas in human care. Chinese colleagues maintain an up-to-date studbook of these vulnerable animals. Zoo scientists developed the formula used to make breeding recommendations for the entire giant panda population in human care, ensuring that it is genetically healthy.
Scientists are working to preserve 90 percent of the genetic diversity of the giant panda population in human care. Panda breeding season is a race against the biological clock. It only comes once a year, and the giant panda team, including scientists from the Smithsonian Conservation Biology Institute's Center for Species Survival, and vets, keepers and biologists from the Zoo's animal care teams, must be ready. Giant panda females, like Mei Xiang, ovulate for just 24 to 72 hours. To identify the opening of that tiny window, animal keepers carefully watch Mei Xiang for any behavioral sign of estrus.
The low nutrient value of bamboo figures prominently in the biology of the giant panda. They have extremely powerful jaws and associated muscles to crunch through the woody stems of bamboo. Each hand bears a specialized metacarpal bone in the wrist that functions as a thumb would in humans, to allow them to grasp the circular bamboo stalks.
While other herbivorous animals, such as antelope, zebras, or rabbits, have very long digestive tracts, the giant panda retains an essentially bear-like digestive tract. Thus, the digestive efficiency of the bamboo they consume is quite low. Examination of the feces demonstrates that their food has been only partially digested. The low nutrient value of their food and their low digestive efficiency results in an animal that is constrained to a low-metabolism.
This lifestyle explains why giant pandas sleep so often and why they eat such enormous amounts of bamboo. Individuals do not travel long distances, and males will establish territories that are not particularly large compared with other species in the Order Carnivora.
Adult females average about pounds in weight, with males sometimes reaching pounds. Their hair is very dense, conserving their body heat in their cold habitats. Their iconic coloration remains a mystery to scientists but may aid with camouflage. Females are fertile for only a very short period of time and exhibit delayed implantation. Although twins are not unusual, a mother will typically only rear one cub.
Adults are solitary, with mating pairings being quite brief. The tiny cubs are altricial, or not born in an advanced state of development, and are completely helpless, blind and deaf, and without the fur necessary to regulate their own body temperatures.
As a result, maternal care is extensive. Cubs do not begin eating bamboo until they are around a year old. When twins are born in zoos, extraordinary measures are taken to train the female to accept swapping of her cubs regularly 24 hours a day, so that she only cares for one a time, but that both receive adequate care.
Bai Yun was not on display for much of Friday, but no one seemed to notice with Xiao Liwu content to put on a show. He got up from his sitting spot, climbed across logs in the enclosure, grabbed another bamboo stalk, leaned back and started to chew again. Each movement was captured by dozens of smartphones. Molnar and Bradley J. Fikes, who contributed to this report, work for the San Diego Union-Tribune. He is an award-winning New Jersey, California and national reporter.
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Facebook Twitter Show more sharing options Share Close extra sharing options. Bai Yun and another giant panda are leaving San Diego Zoo. The last day they can be viewed by the public is expected to be April By Phillip Molnar.
How the San Diego Zoo helped unlock the mystery of panda sex and parenting » Advertisement. Xiao Liwu, shown at 7 months, tries to get mom Bai Yun to play in Phillip Molnar.
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