Body length: 120 to 150 cm
Average weight: 67 to 160 kg (146 to 353 lbs)
Lifespan: 14 to 20 years (wild)
Distribution: Minshan Mountains of Sichuan and Gansu provinces of China, Qinling Mountains of Shaanxi Province, China
Status: Endangered (IUCN), Appendix I (CITES)
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Ursidae
Subfamily: Ailuropodinae
Genus: Ailuropoda
Species: Ailuropoda melanoleuca David 1869
English: Giant panda
Chinese: xióng māo (bear cat), huā xióng (spotted bear), zhú xióng (bamboo bear)
Taiwan: māo xióng (cat bear)
DNA fingerprinting has revealed different genetic patterns in giant pandas and a separation into 2 subspecies [25]. Based on cranial and dental morphology measurements and comparison of pelage coloration, the new subspecies Ailuropoda melanoleuca qinlingensis from the Qinling Mountain range is characterized by a smaller skull size, larger molar size, and different pelage coloration (i.e., dark brown on chest and venter) compared with the subspecies A. m. melanoleuca primarily found in Sichuan [26]. Reconstructing the panda’s demographic population history revealed an approximate 300,000-year separation between the Qinling and the non-Qinling populations. Also, a divergence of the non-Qinling subspecies into 2 geographically divided and genetically distinct groups occurred approximately 2,800 years ago [27].
As an endangered species, the giant panda is the symbol of conservation as the icon of the World Wide Fund for Nature (WWF), and probably is the most beloved animal worldwide. Historically, the systematic classification of the giant panda posed a challenge to taxonomists, but DNA analyses through molecular studies indicate that the giant panda is more closely related to the bear family (Ursidae) than to the raccoon (Procyonidae) family.
With its striking black-and-white coat, and a white face with oval and black eye patches, the giant panda’s pelage coloration pattern is unique among mammals. These black eye spots have been suggested to have evolved to reduce the “glare” effect of light reflecting off snow. Giant pandas inhabit Southwest China and can be found primarily in cool, damp, foggy mountainous forests, where bamboo (a type of giant grass in the family Poaceae) forms their nutritional base and comprises approximately 98% of their diet. Despite its diet, the panda retains the digestive system of a carnivore, which is relatively shorter than the digestive system characteristic of a typical herbivore. Therefore, the panda can only partly digest bamboo and must consume a daily ration of approximately 10–18 kg of bamboo to obtain sufficient calories and nutrients. The panda also has evolved a thumb-like appendage (also known as the “pseudo-thumb”) on each of its front paws. This thumb-like appendage (an extended radial sesamoid bone) is not opposable, but allows for a firm and well-directed grip when eating and handling bamboo. Pandas have large skulls with wide jawbones and powerful jaw muscles, which allow them to crush the tough bamboo stems.
Giant pandas are solitary and make little direct contact with conspecifics except during breeding season in spring. However, social dynamics appear to be predominantly regulated via scent communication. Scent marks are of great importance for marking home ranges and for advertising reproductive status. A male’s home range may overlap with smaller home ranges of several females, and several males may compete for breeding access to a female.
Adult panda body weight ranges from 67 to 150 kg. The species is sexually dimorphic, with males weighing an average of 10−20% more than females. Newborn pandas weigh approximately 100 g and are therefore approximately 1/900th of their mother’s size. With the exception of marsupials, newborn pandas are the smallest newborns within the mammalian phylogenetic tree. Pandas are weaned at approximately 18 months and reach sexual maturity at approximately 4−5 years. Similar to some of its ursid relatives (e.g., Andean bear [Tremarctos ornatus], sloth bear [Melursus ursinus], sun bear [Helarctos malayanus]), pandas do not hibernate; this behavior is presumed to be due to the year-round availability of food.
| Age | Body weight | Head length | Body length | Tail length | Fore foot | Hind foot | |
|---|---|---|---|---|---|---|---|
| Adulta | 10.5 | 100.1 | 37.4 | 123.4 | 15.4 | 17.3 | 22.2 |
| Subadulta | 3.2 | 94.4 | 37.9 | 112.1 | 15.7 | 18.5 | 22.2 |
| Juvenilea | 1.5 | 54.6 | 35.3 | 101.4 | 13.4 | 15.9 | 19.8 |
| Infantb | 0.2 | 3.7 | 17.4 | 46 | 7 | − | − |
Length measurements in cm and mass in kg. a Adopted and modified from [23]. b Adopted and modified from [16].
Sexual dimorphism: Males weigh an average of 10–20% more than females.
For many years the precise taxonomic placement of the giant panda within the order Carnivora has been subject of intense debate, particularly regarding whether giant pandas are more closely related to bears than to raccoons. However, studies indicate that the taxon of the giant panda is a sister group to other ursids [2–5].
The main food source of the giant panda is bamboo, which is available year-round; therefore, pandas do not need to hibernate. During most of the year, adult giant pandas live solitary lives with defined but overlapping home ranges [6]. The annual mating season between March and May is the only time when both sexes encounter each other [6, 7]. Females are mono-oestrous and are able to conceive for a short time frame of 1–3 days during ovulation [6]. Therefore, communication signals (e.g., olfactory and vocal) play an important role in coordinating mating efforts [8–14].
Female giant pandas follow a delayed implantation schedule wherein the fertilized embryo does not immediately attach to the uterine wall. Delayed embryo development results in variable gestation periods, so pandas give birth 85–185 days after mating. Births usually occur between August and September, with 1–2 newborns being typical. Cubs are born blind, with very little fur, and are completely helpless [6, 15, 16]. Weighing approximately 100 g (or 1/900th of the size of the mother), a giant panda cub is one of the smallest mammal newborns relative to its mother’s size [17]. Giant panda cubs do not open their eyes until they are 6–8 weeks of age and are not mobile until 3 months of age [18]. Cubs are highly vocal and emit a wide range of sounds such as a “squawk”, a high-pitched “squall” and a pulsed “” [19, 20]. The altricial condition of the giant panda neonate places a high demand of maternal care on the mother for nursing and other related behaviors such as direct contact [7]. In contrast to other bears, female giant pandas carry their cubs on their bodies more or less continuously for the first 1–2 postnatal weeks. Adult females are completely engaged in facilitation of suckling, thermoregulation, grooming, and bowel and bladder stimulation of the cubs [16]. A cub may nurse for 8–9 months and weaning occurs at approximately 12 months of age. However, a cub will remain with its mother for up to 24 months. As a result of the time investment required to raise young to independence, a female giant panda generally gives birth to only 5–8 young throughout her lifetime [6]. Infants and juveniles may fall prey to predatory mammals, such as the common leopard (Panthera pardus), but data on predation are scarce [21].
| Gestation (days) | Maximum litter size | Infant lifespan (years) | Subadult lifespan (years) | Adult lifespan (years) | Maximum age (years) |
|---|---|---|---|---|---|
| 85 - 185a | 3a | 1 - 1.53 | 1.6-4.5c | >4.5c | 34d |
Sources: a [16]; b [22]; c [23]; d [24].
Mating system: Polygynous
Breeding interval: Every 2 years
Breeding season: March to May
Independence: 18 to 24 months
According to the 2006 survey coordinated by the State Forestry Administration of China and WWF [28], 1,600 giant pandas currently are living in the wild. However, based on microsatellite analyses using fecal DNA, it is estimated that there are currently approximately 2,500–3,000 free-ranging individuals [29]. In 2013, there were 376 giant pandas living in captivity worldwide [24].
The giant panda’s geographic range includes 24 isolated populations [30, 31]. These 24 populations are found in temperate, deciduous, and coniferous forests at the edge of the Tibetan Plateau in Sichuan and Gansu provinces, and in the Qinling Mountains in Shaanxi Province [32].
Green = Extant, Yellow = Possibly Extant. Map data courtesy of IUCN Redlist.
The giant panda prefers mountainous regions where bamboo (e.g. Fargesia denudata in the Minshan mountains) is abundant [6]. In general, giant pandas avoid fragmented forests (i.e. forests that are discontinuous usually due to separation by roads, agriculture, or other human development) yet prefer mixed forests (i.e. forests with two or more dominant tree species) at variable scales [33].
Generally, a limited amount of bamboo is available at elevations between 1,950 m and 2,160 m. Giant pandas exhibit winter and summer preferences that can be predicted according to elevation [34]. During the winter months, giant pandas do not hibernate and instead migrate to elevations below 1,950 m. Relative to other bears; giant pandas do have a thick layer of fat that would allow them to tolerate extremes in cold temperatures. At these lower elevations, giant pandas are able to forage on bamboo stalks, avoiding leaves. In the cold months, bamboo leaves do not contain as much protein. Due to their thick fur, pandas prefer cooler temperatures during the summer months and migrate to elevations above 2,160 m, as high as bamboo species will grow [34]. In addition, giant pandas prefer gentle slope gradients (e.g., 10−20°) when available, but select for steeper slopes (i.e., >30°) naturally found at higher elevations during the summer months [33, 35, 36]. Gentle sloped gradients are usually associated with old-growth forests with nourishing undergrowth of bamboo and streams. Gentle sloped gradients are especially preferable by females who can select den sites in stands of old growth and large coniferous trees to raise their young.
During winter months, an understory consisting of the bamboo species Bashania fargesii is abundant; whereas, the bamboo species Fargesia qinlingensis is available during summer months. Local people refer to areas of bamboo grooves where culms are short (i.e., <2 m in length) and dense because of giant panda foraging activity as “ZhuYangZi” [33, 35, 36].
Average home ranges (i.e., area used by giant panda but not necessarily defended in whole) of individual giant pandas vary between 3.9 km2 and 15 km2 [29, 30, 37, 38]. Giant pandas use scent-marking to delineate their home ranges in areas where ranges overlap [39]; this helps sustain a physical separation between individuals [6]. Both males and females have overlapping home ranges; however, adult males will overlap with many females and nearby males, whereas some females will maintain sole ranges. Females can be sedentary at times, and may not frequent parts of their home ranges for weeks or months. In these areas of female home-range exclusivity, the average core area (i.e. area that no other giant panda will frequent mostly as a result of avoidance) varies from 0.3 to 0.4 km2. Conversely, males do not exhibit core area usage within their home ranges. The size of home ranges for males is related to the distribution and abundance of reproductive females [39]. During the winter months, male home ranges can vary from 1.1 km2 to 6.0 km2 and 1.3 km2 to 4.3 km2 during the summer months. During the winter months, female home ranges can vary from 2.3 km2 to 4.5 km2 and 0.7 km2 to 3.0 km2 during the summer months [40]. Further research is needed to confirm these numbers.
Although it is considered an omnivore with a typical gastro-intestinal tract of a carnivore, the giant panda’s primary diet is bamboo [39]. The giant panda lacks a caecum, has one stomach, and has a short intestine, all of which are characteristic of a carnivore. On average, the panda consumes 10–18 kg of bamboo/day, and processes 17% of dry matter of bamboo [6]. Thus, pandas must spend a large portion of their day on foraging activities to find and consume enough quality food. Pandas prefer different bamboo species and parts depending on the time of year. Based on observations in Wolong Reserve, pandas consume leaves and stems of Bashania fangiana bamboo during most of the year at elevations from 2,600 to 3,400 m [39]. During the spring months (e.g., May), pandas move to lower elevations (e.g., below 2,600 m) and consume Fargesia robusta bamboo. During late spring and early summer, pandas resume feeding on Bashania bamboo when the shoots are fibrous and developed. During winter months, pandas will select F. robusta bamboo when access to Bashania bamboo is limited because of snow cover or a die-back of Bashania bamboo [6].
Presently, the giant panda is classified as “Vulnerable” on the International Union for the Conservation of Nature (IUCN) Red List under Criterion 2a(i); under Criterion 1 of the Chinese Wildlife Conservation Law of 1988; and on Appendix I of the Convention on International Trade in Endangered Species (CITES) as a result of habitat loss, deforestation, and poaching [41]. Historically, the giant panda has been listed since 1986 as “Rare” by IUCN, with population estimates of 1,600 giant pandas living in the wild and 376 individuals in captivity [24].
Strict laws protect the giant panda, and commercial trade of pandas and panda products is prohibited. In the 1980s and 1990s, the Chinese government began a program to loan giant pandas to a number of international zoos, despite the strong criticism by CITES for trading this animal for commercial reasons. Pandas are loaned at a rate of US$1M/year, though this rate can vary depending on individual contracts with associated zoos. Since the establishment of the loan program and the raised funds through it, scientific research on pandas has expanded considerably, covering a wide range of research topics.
Concerted efforts to increase the ex situ panda population have been achieved through successful captive-breeding programs. The goal of these breeding programs has been to reintroduce captive-born pandas into the wild [42]. In April 2006, “Xiang Xiang” was the first giant panda to be released into the wild since captive breeding began >4 decades ago. Unfortunately Xiang Xian was found dead approximately 1 year later as a result of an attack by a conspecific.
Poaching of pandas has been largely controlled; therefore, the primary threat to giant pandas currently is habitat loss [39]. In the 1960s, the first nature reserves were established to promote protection of giant panda habitat. Currently, 64 nature reserves form a conservation network to protect panda habitats [44]. However, because of habitat degradation and fragmentation, giant pandas remain as 24 isolated populations [30, 31]. Migration corridors are critically important to link the isolated panda populations and to facilitate panda migration, dispersal, and genetic exchange among populations [44]. However, presently, due to natural barriers induced anthropogenic disturbances, much of the habitat in the panda nature reserve network is still poorly connected [45].
China allows land transfers or leases from farming households to external enterprises. Under this system, land access and rights are granted to commercial loggers; firewood collectors; and non-timber forest producers, tourism operators, and other industrial operations and developments [46]. These activities are contributing to the deforestation, alteration, degradation, and destruction of China’s forests, including approximately 3,457 km2 of giant panda habitat. Further, projected changes in both bamboo and panda distribution driven by climate change will pose a significant challenge to giant panda management [47].
The giant panda is viewed ecologically as an “umbrella” species. Pandas inhabit forests of the Yangtze River zone, which is an important water conservation area that controls soil erosion and reduces the severity of flooding [32]. Conserving giant panda habitat benefits many other species that share the same living space. Protecting giant pandas also results in the creation, protection, and maintenance of healthy ecosystems that provide drinking water for millions of people downstream of the giant panda’s range.
Mag. Anton Baotic – Department of Cognitive Biology, University of Vienna, Austria
Sandra Elvin, PhD – Environmental Studies, York University, Toronto, Ontario
IUCN Redlist: https://www.iucnredlist.org/species/712/121745669
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