Are Pandas Bears? Giant and Red Panda Family Tree

The giant panda is a true bear

The giant panda (Ailuropoda melanoleuca) is one of eight living bear species, alongside the brown, American black, Asiatic black, polar, sloth, sun and spectacled bears. It has the classic bear body plan: a heavy build, short tail, plantigrade feet (walking on the soles like people do) and a large head.

Within the bear family it sits in its own subfamily, Ailuropodinae. Molecular studies show that the panda’s lineage split off from the ancestors of all other living bears very early, with many molecular estimates placing the split around 19 million years ago. That makes it the most distinct living bear, roughly equally related to all the others.

Its unusual features, such as the round head, flat grinding molars and bamboo diet, are adaptations that developed after that split, not signs that it belongs elsewhere. Fossils of extinct relatives, such as the much smaller Ailuropoda microta, show pandas eating bamboo for at least two million years.

A debate that lasted more than a century

When the French missionary Armand David sent the first giant panda skin to Paris in 1869, he described it as a bear, Ursus melanoleucus. The next year the zoologist Alphonse Milne-Edwards studied its skeleton and teeth, noticed similarities with the red panda and placed it in a new genus, Ailuropoda. That started a long argument.

For most of the 20th century, scientists split into camps. Some grouped the giant panda with the red panda and raccoons, some with the bears, and some gave both pandas a family of their own. In 1964 the anatomist D. Dwight Davis published a detailed study of the giant panda’s anatomy and concluded that it was essentially a specialized bear.

The question was largely settled in 1985, when a team led by Stephen O’Brien published molecular evidence in the journal Nature showing that the giant panda belongs with the bears, while the red panda belongs elsewhere. The giant panda genome, published in 2010, and many later studies confirmed this result.

The red panda is not a bear

The red panda (Ailurus fulgens) is a small, cat-sized mammal of the eastern Himalayas and southwestern China, typically weighing about 3–6 kg (7–13 lb), with reddish fur and a long ringed tail. It was described in 1825, more than 40 years before the giant panda, and for that whole time it was simply called “the panda”.

Scientists once placed the red panda in the raccoon family or close to the bears. Genetic studies now put it in its own family, Ailuridae, within a larger group called Musteloidea. That group also includes raccoons and their relatives, skunks and the weasel family. The red panda’s lineage goes back about 20 million years, and fossil relatives have been found in Europe and North America.

Why two unrelated animals look alike in some ways

Giant and red pandas share some striking features despite being distant relatives:

Both have an enlarged wrist bone, the radial sesamoid, that works like a thumb for gripping bamboo. Both have strong jaws and broad cheek teeth. These traits evolved independently, a process called convergent evolution, because both animals adapted to the same tough food in the same mountain forests. Fossils suggest the red panda’s false thumb may first have helped its ancestors climb, and only later was used for holding bamboo.

For a full side-by-side look, see red panda vs giant panda.

Where the name panda comes from

The origin of the word panda is not known for certain. It entered English through French in the 19th century as a name for the red panda, and a commonly suggested source is a Nepali word, but this is not proven. When the giant panda became known in the West, it was called the “giant panda” to tell it apart, and the red panda became the “lesser panda” or “red panda”.

In Chinese, the giant panda is usually called da xiongmao, meaning “big bear cat”, which reflects the same old confusion over which animal it most resembles.

Do pandas behave like other bears?

In many ways, yes. Giant pandas are solitary, mark their ranges with scent, climb trees well and raise tiny, helpless cubs like other bears. Their main difference is that they do not hibernate, because a bamboo diet cannot build enough fat for a long winter sleep. To compare, see do bears hibernate?