Today, there are less than 2,000 wild red pandas left in the bamboo forests of China, Nepal, and Burma. Their handsome coloration blends with the red moss and white lichens that grow so abundantly in the forests where they live. They feed upon bamboo (both the stalks and the leaves), berries, mushrooms, bark, and birds’ eggs. They are a small animal, seldom weighing more then 14 pounds. And like so many other species of wildlife, they are endangered.
Photo of red panda.
5 million years ago, red pandas were more widespread throughout the northern hemisphere. Though Miocene age fossil sites are rare in North America, fossils of red pandas have been discovered at 2 of them. Specimens of red panda dating to the Miocene were found at one locality in Washington state and at the spectacular Gray Fossil Site in northeastern Tennessee.
Skull of red panda found at the Gray Fossil Site in Tennessee. It probably ranged over most of North America during the Miocene.
The Miocene aged species of red panda (Pristinailurus bristoli) is a now extinct species different from the modern red panda (Ailurus fulgens). Nevertheless, anatomical characteristics between the 2 are similar enough for there to be no doubt it was a type of red panda. Perhaps it fed on the species of bamboo (Arundirea gigantea) that still grows in the south and until the 19th century was extremely abundant in extensive canebrakes that once covered hundreds, if not thousands, of square miles. Scientists have discovered macrofossils of bamboo cane at the Gray Fossil Site.
Despite the name, the red panda is not at all closely related to the zoo-friendly and famous giant panda (Ailuropoda melanoleuca). According to the latest genetic studies, the giant panda is part of a parallel sidebranch of the bear family. The red panda is in a family all by itself, located on the evolutionary tree between raccoons and weasels. Like giant pandas, red pandas have an opposable thumb for grasping bamboo, but this is an example of convergent evolution and not a shared inherited trait from a closely related ancestor.
Here’s a link to a youtube video of 2 red pandas playing. They are adorable. http://www.youtube.com/watch?v=tXAhGyX7aGc
Paleobotanical studies of the Gray Fossil Site indicate a remarkable affinity with the environment where red pandas live today. The vertebrate fossils at this site accumulated between ~7 million – ~4.5 million years ago. This corresponds to a Late Miocene and Early Pliocene Age. During this era, most of America and Asia consisted of forest with a similar composition of plant and animal species. The climate was stable and mostly subtropical over most of the continents. Instead of hot summers and cold winters, like we enjoy (or not) at the present time, the seasons were separated into wet monsoon winters alternating with drought-like summers. Macrofossils of Sinomenium, a member of the moonseed family, were found at the Gray Fossil Site. This species of woody vine no longer occurs in North America but does grow in regions where modern red pandas live today. Scientists also found seeds from 3 species of grapes at the Gray Fossil Site. They determined that 1 of the species of grapes was closely related and probably ancestral to a species of extant American grape, but the other 2 were kin to Asian species of grapes.
Moonseed (Sinomenium)–a woody vine that currently lives in Asia but also used to live in North America in the environment with red pandas. The forest that covered both North America and Asia then consisted mostly of oaks and pines and many of the species are still extant. Plant and animal species from both continents were very similar, and in some cases the same. The Miocene forest ecosystem in the northern hemisphere was stable and mostly continuous over both continents.
When Ice Ages began to occur early in the Pliocene, desert and grassland environments expanded while the mostly homogenous forest that prevailed during the Miocene contracted. The early Pliocene was particularly dry, and forested environments for the most part may have cyclically been restricted to riverine galleries. This ecological change spelled the end of the red panda’s existence in North America and caused an overall faunal turnover that led to the rise of late Pliocene/early Pleistocene species.
I was going to write a subheading about the Gray Fossil Site, but I found so many studies published since its discovery 12 years ago, that it is deserving of a feature essay on this blog. I’ll elaborate more about the site next week.
References:
Flynn, John; et. al.
“From Whence the Red Panda”
Molecular Phylogenetics and Evolution 17 (2) Nov 2000
Gong, F.; et. al.
“Vitis Seeds (Vitacea) from the Late Neogene Gray Fossil Site, northeastern, Tennessee, USA”
Review of Paleobotany and Palynology 162 (2010)
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