Strictly speaking, brown giant pandas should be called brown-and-white giant pandas. The black fur on their bodies has turned brown.
The first recorded brown giant panda was named “Dandan.” On March 26, 1985, Dandan was discovered in the Foping Nature Reserve of Qinling, Shaanxi Province. At the time of discovery, Dandan was very weak. After being rescued, she was taken to the Xi’an Zoo for care. Since Dandan, five more brown-and-white giant pandas have been discovered. All of them live in the core area of Qinling and belong to the Qinling subspecies, which are relatively larger in size compared to other giant pandas.
Scientists have conducted long-term research on the reasons behind the fur color change in brown-and-white giant pandas. Currently, there are three main theories:
- Environmental Factors: This theory suggests that brown-and-white giant pandas live in the same area where certain trace elements in the water, soil, and climate affect melanin synthesis. These trace elements are ingested by the pandas through drinking, eating, and breathing, leading to a decrease in melanin in their fur. However, this theory is not flawless, as only a small portion of pandas in the Qinling area are brown-and-white.
- Genetic Expression: This theory posits that the fur color change is a result of genetic expression. In organisms, genes can be dominant or recessive. Dominant genes express themselves in visible traits, while recessive genes only express traits when they are in a homozygous recessive state (both genes are recessive). Additionally, there are cases of incomplete dominance and polygenic traits. Most giant pandas have dominant genes for black-and-white fur, whereas brown-and-white genes are either recessive or non-existent.
- Atavism: This theory suggests that the brown-and-white fur is an atavistic trait. Compared to the Sichuan subspecies, the Qinling subspecies has rounder heads and shorter snouts, resembling their ancestral giant panda forms. Scientists have observed that many normally colored Qinling pandas have some orange fur on their chests and abdomens. Combining these observations, scientists hypothesize that the brown-and-white fur might be an atavistic phenomenon.
However, the mothers and offspring of the currently discovered brown-and-white pandas all have normal black-and-white fur. Since male pandas do not participate in rearing offspring, it is difficult for scientists to conduct comprehensive genetic studies. Therefore, the question of why some giant pandas have brown-and-white fur remains unanswered.
Related Knowledge
Why Do Brown-and-White Giant Pandas Only Appear in Qinling?
Approximately 300,000 years ago, giant pandas in the Qinling Mountains diverged from those in other regions. One theory suggests that due to geographical isolation, these pandas lost contact with their counterparts in other areas, resulting in a lack of gene flow. However, this theory still requires more robust evidence to be fully validated.
Other Animals with Fur Color Variations:
In addition to giant pandas, several other animals exhibit rare fur color variations:
- Migaloo: A white humpback whale living in Australian waters, known as the only known white humpback whale in the world.
- White Lion: A rare color variant of the African lion.
- White Tiger: A rare color variant of the Bengal tiger.
- Black Panther: A term used for leopards with black fur.
- White Black Bear: An exceptionally rare variant of the American black bear.