The giant panda (Ailuropoda melanoleuca), also known as the panda bear (or simply the panda), is a bear species endemic to China.[4] It is characterised by its bold black-and-white coat and rotund body. The name "giant panda" is sometimes used to distinguish it from the red panda, a neighboring musteloid.
For many decades, the precise taxonomic classification of the giant panda was under debate because it shares characteristics with both bears and raccoons. However, molecular studies indicate the giant panda is a true bear, part of the family Ursidae. These studies show it diverged about 19 million years ago from the common ancestor of the Ursidae; it is the most basal member of this family and equidistant from all other extant bear species. The giant panda has been referred to as a living fossil.
The word panda was borrowed into English from French, but no conclusive explanation of the origin of the French word panda has been found. The closest candidate is the Nepali word ponya, possibly referring to the adapted wrist bone of the red panda, which is native to Nepal. The Western world originally applied this name to the red panda.
In many older sources, the name "panda" or "common panda" refers to the lesser-known red panda, thus necessitating the inclusion of "giant" and "lesser/red" prefixes in front of the names. Even in 2013, the Encyclopædia Britannica still used "giant panda" or "panda bear" for the bear, and simply "panda" for the red panda, despite the popular usage of the word "panda" to refer to giant pandas.
Adults measure around 1.2 to 1.9 metres (3 feet 11 inches to 6 feet 3 inches) long, including a tail of about 10–15 cm (4–6 in), and 60 to 90 cm (24 to 35 in) tall at the shoulder. Males can weigh up to 160 kg (350 lb). Females (generally 10–20% smaller than males) can weigh as little as 70 kg (150 lb), but can also weigh up to 125 kg (276 lb). The average weight for adults is 100 to 115 kg (220 to 254 lb).
The giant panda has a body shape typical of bears. It has black fur on its ears, eye patches, limbs and shoulders. The rest of the animal's coat is white.[42] The bear's distinctive coat appears to serve as camouflage in both winter and summer environments. The white areas may serve as camouflage in snow, while the black shoulders and legs provide crypsis in shade. Studies in the wild have found that when viewed from a distance, the panda displays disruptive coloration while close up, they rely more on blending in. The black ears may signal aggressive intent, while the eye patches might facilitate them identifying one another. The giant panda's thick, woolly coat keeps it warm in the cool forests of its habitat. The panda's skull shape is typical of durophagous carnivorans. It has evolved from previous ancestors to exhibit larger molars with increased complexity and expanded temporal fossa. A 110.45 kg (243.5 lb) giant panda has a 3D canine teeth bite force of 2603.47 newtons and bite force quotient of 292.[citation needed] Another study had a 117.5 kg (259 lb) giant panda bite of 1298.9 newtons (BFQ 151.4) at canine teeth and 1815.9 newtons (BFQ 141.8) at carnassial teeth.
Despite its taxonomic classification as a carnivoran, the giant panda's diet is primarily herbivorous, consisting almost exclusively of bamboo. However, the giant panda still has the digestive system of a carnivore, as well as carnivore-specific genes, and thus derives little energy and little protein from consumption of bamboo. The ability to break down cellulose and lignin is very weak, and their main source of nutrients comes from starch and hemicelluloses. The most important part of their bamboo diet is the shoots, that are rich in starch which they have a higher capability of digest than strict carnivores, and have up till 32% protein content. During the shoot season, which lasts from April to August, they put on a lot of weight, which allows them to get through the nutrient-scarce period from late August to April, when they feed mostly on bamboo leaves. Pandas are born with sterile intestines and require bacteria obtained from their mother's feces to digest vegetation. The giant panda is a highly specialised animal with unique adaptations, and has lived in bamboo forests for millions of years.
The average giant panda eats as much as 9 to 14 kg (20 to 30 lb) of bamboo shoots a day to compensate for the limited energy content of its diet. Ingestion of such a large quantity of material is possible and necessary because of the rapid passage of large amounts of indigestible plant material through the short, straight digestive tract. It is also noted, however, that such rapid passage of digesta limits the potential of microbial digestion in the gastrointestinal tract, limiting alternative forms of digestion. Given this voluminous diet, the giant panda defecates up to 40 times a day. The limited energy input imposed on it by its diet has affected the panda's behavior. The giant panda tends to limit its social interactions and avoids steeply sloping terrain to limit its energy expenditures.
The giant panda is a terrestrial animal and primarily spends its life roaming and feeding in the bamboo forests of the Qinling Mountains and in the hilly province of Sichuan. Giant pandas are generally solitary. Each adult has a defined territory and a female is not tolerant of other females in her range. Social encounters occur primarily during the brief breeding season in which pandas in proximity to one another will gather. After mating, the male leaves the female alone to raise the cub.
Pandas were thought to fall into the crepuscular category, those who are active twice a day, at dawn and dusk; however, Jindong Zhang found that pandas may belong to a category all of their own, with activity peaks in the morning, afternoon and midnight. The low nutrition quality of bamboo means pandas need to eat more frequently, and due to their lack of major predators they can be active at any time of the day. Activity is highest in June and decreases in late summer to autumn with an increase from November through the following March. Activity is also directly related to the amount of sunlight during colder days.
Pandas communicate through vocalisation and scent marking such as clawing trees or spraying urine. They are able to climb and take shelter in hollow trees or rock crevices, but do not establish permanent dens. For this reason, pandas do not hibernate, which is similar to other subtropical mammals, and will instead move to elevations with warmer temperatures. Pandas rely primarily on spatial memory rather than visual memory.
Though the panda is often assumed to be docile, it has been known to attack humans, presumably out of irritation rather than aggression.
Pandas have been known to cover themselves in horse manure to protect themselves against cold temperatures.
