Giant pandas are by nature solitary animals, most of the time avoiding direct contact with others of their own kind. Recent studies have changed the once thought idea that giant pandas rarely came together except during the breeding season. Now recent studies by researchers suggest that pandas live in overlapping territories and encounter each other outside of the once believed "breeding period." It is also believed that the pandas are familiar with their neighbors by their scent marks, urine and feces. Large groups of pandas have been seen together during breeding season which normally comprise of multiple males and a single female.

In their dense habitat, their coat may help make them conspicuous to each other and prevent them from surprising themselves by approaching too close to another of their own kind.

Even in captivity where there may be as many as 10-12 bears occupying the same caged area, rarely will you see them play with or acknowledge each other. They will find an unoccupied place in the area and sit down, content to munch on bamboo or other food items totally oblivious of each other.

But at crucial stages in their lives giant pandas, like all solitary mammals, are forced to spend time with each other. In the spring males and females must seek each other out in order to mate.

Giant pandas rely heavily on their sense of smell. They use their sense of smell to forage for food as well as knowing when they are crossing into another's territory.

Scent marking is a vital role in the communication of the giant pandas to each other. It is like the community bulletin board to all passer bys. The giant panda sprays urine (sometimes known as their "scent") which can be detected by other giant pandas and is believed to be unique to each the same way as DNA is unique to each human. It is also believed that the scent can distinguish the sex, age, breeding condition and other vital communications of the giant panda leaving the scent by other giant pandas. It can be detected for up to 4 months and is used as a calling card by females and for territory marking as well as enticing females closer for mating by the males.

More frequent scenting by the female signals that the estrus period (the period of heat, or rut; or the period of maximum sexual receptivity of the female) is nearby and within days the female giant panda will be at peak estrus and thus ready to mate.Peak estrus in the female lasts from one to three days, and the gestation period varies from about 97 to 165 days.

During the mating season the males attempt to ward off rival males by doing what is known as a "hand-stand scent mark." This is believed to be an intimidation factor to other males. Common theories suggest the reason for this is the higher the male panda can scent the larger the male must be, thus hopefully scaring off smaller males.

The giant panda usually reaches sexual maturity, and are known to begin mating, at 5.5 to 6.5 years six years of age. Mating usually takes place sometime between the months of March and May. Courtship is done by the female squirting urine as a calling card for the males. The males will then follow the scent to the female. The males will gather around and compete for the access to a female in heat. During this time, giant pandas are highly vocal animals. The males bark and roar as they try to intimidate each other, and courting pairs emit a goat like bleating sound. The female perches in a tree while the male remains on the ground fending off any rivals.

Through a process known as delayed implantation the fertilized ovum divides a few times and then floats free from the uterine wall and its development is suspended. Sometime in June or July, the embryo will re-attach itself to the uterine wall and the growth process begins.

In the months August or September, one or two cubs are born weighing 3 to 5 ounces each (1/900th of the mother's weight) in a sheltered den made by the mother of twigs and leaves. The cubs are born blind and hairless. The mother usually, but not always, cares only for the dominant cub and the other cub is generally rejected and dies within days of birth.

The mother will hold the cub to her chest with both paws and continues in this fashion until the youngster squirms away. The mother then captures the cub and the procedure starts over again. The chosen cub will become the mother's constant companion for the next 18 months or more. The mother will cuddle and nurture her cub with the love and tender care similar to a human mother and at times the mother has been seen in captivity, while asleep, to roll over onto her cub, smothering the cub. The mother will "cry" (sounds like a whimper) and go into a deep depression and may not eat or move for days grieving for her cub.

The cubs' skin will start to turn gray in the areas where the black hair will eventually start to grow. Their eyes open at 1 1/2 to 2 months and the cub becomes mobile at approximately 3 months of age. Giant panda cubs will start eating bamboo at around six months of age and at nine months are totally weaned from their mother. At about one year of age the cub will weigh around 35 kilograms (75 pounds).

The survival of the giant panda cubs is totally dependant on the skill of the mother in both protecting them as well as teaching them the basics of what to eat, where and how to get it and how to cope with danger. At 15-18 months the cub becomes totally independent having learned the "language" and necessary hunting and foraging skills they will need for their adult life. At this time the mother will drive off the cub as she prepares to mate again.

Although giant pandas rarely fight they will and do let other's know of their disapproval by grunting and with body language. Giant pandas signify aggression by lowering their heads and staring at their opponents. The giant panda is a generally a passive animal and not initiate to attack man or other animals. Giant pandas, however can become violent when provoked or surprised. Generally when hearing abnormal sounds the giant panda will escape the area immediately. Should they become trapped the giant panda will cover their face with their paws often hiding its eye-patches and curl up. This gesture states that they are scared and/or angry. This position is adopted by females during mating, and also by captive animals that are being harassed by humans - particularly vets with anesthetic darts. At close range, aggression is signaled by a swipe with a paw, or by a low-pitched growl or bark that will generally send an opponent (another giant panda) scampering up the nearest tree.

Pandas are generally not very vocal when they are alone.The most common sounds, are "bleating," a sheep like sound which signifies a social call for contact. When a female is in heat, she will chirp. A honk indicates mild alarm over a minor disturbance. The giant panda also belts out a very loud moan, roar, growl, and/or bark to indicate a range of moods and varying degrees of aggression.

There has been only one known attack on a human: The panda ripped open a thigh and then bit the other leg after being frightened by a female worker at a reservation falling down an embankment.