.jpg)
Bristol’s Panda (Pristinailurus bristoli), found only at the Gray Fossil Site, is an ancient North American relative of the living Red Panda (Ailurus fulgens). Known from intact skeletons, it is the most complete fossil ailurid from North America and most complete ailurine found anywhere else in the world.
Etymology
Its
genus name (Pristinailurus) comes from the Latin word pristinus meaning “former” or
“previous”, and Ailurus for the living
Red Panda (Ailurus fulgens) to which the
fossil species is closely related. The species name (bristoli) is named for Larry Bristol who discovered the first fossils
from Bristol’s Panda. Commonly, this species is also known as “Bristol’s
Appalachian Panda.” The word “panda” itself is derived from the Nepalese term nigalya poonya, which means
“bamboo-eater,” a reference to the diets of the living Red Panda and the
unrelated Panda Bear (Ailuropoda
melanoleuca).
Habitat & Distribution
Bristol’s
Panda is special because it is one of only two ailurine pandas known from North
America. The other is an unnamed Parailurus
species from Washington State, and it is known by a single tooth. Although the
living distribution of Bristol’s Panda was undoubtedly more expansive, fossils
are known only from the late Miocene-early Pliocene locality of Gray,
Tennessee. The environment in which it lived was a forested region with a
subtropical climate as evidenced by the alligator and other fossils unearthed
here.
Physical Attributes
wmkd.jpg)
Bristol’s
Panda differs from the Red Panda in a number of ways, the most obvious being
its much larger size. The fossil panda would have weighed 8 to 15kg (17 to 33lbs)
in life, compared to the modern Red Panda which averages 5kg (11lbs). The skull
of Bristol’s Panda is not as domed and it lacks a sagittal crest suggesting a
weaker bite. However, its snout was longer with larger incisors and canines.
The upper carnassial is also longer and not as wide, suggesting that it was not
as dependent on plant matter as part of its diet.
Bristol’s
Panda shares several physical characteristics with the modern Red Panda which
point to climbing ability. They both have a long tail for counterbalance, broad
paws with recurved semi-retractable claws, and a nimble body with powerful
muscles in the forelimbs and lower back. There are some major differences
between the ancient and modern red pandas. Several aspects of Bristol’s Panda’s
anatomy hint at a more terrestrial existence than its living relative. Compared
to the tree-dwelling Red Panda, Bristol’s Panda has proportionally shorter and
more robust forelimbs while the hind limbs were significantly longer. This body
plan is typical of carnivorans such as civets, small cats, and certain foxes
that actively hunt on the ground while retaining considerable climbing ability.
wmked.jpg) |
| Skull and head comparison of Bristol's Panda (left) and Red Panda (right). |
We
see further evidence of a terrestrial lifestyle in Bristol’s Panda in the arrangement
of its wrist and finger bones. The modern Red Panda has particularly
well-developed “false thumbs” on its front paws that form an effective clamp
for gripping tree trunks and thin branches. The false thumbs of Bristol’s Panda
are proportionally much smaller. This suggests less frequent usage of the
“false thumbs” and overall less time spent in the higher branches of trees.
 |
| Size comparison between the Bristol's Panda and the Red Panda. Note the larger size and proportionally shorter forelimbs, longer hind limbs, and longer body in the Bristol's Panda. |
Ecology & Behavior
The
body proportions of Bristol’s Panda were those of an active and agile predator
that spent most of its time on the ground but could readily climb trees when
necessary. Like many small forest-dwelling carnivorans it was probably
nocturnal and solitary, perhaps sleeping in burrows during the day and emerging
at night to forage. Together with the Woodland Badger (Arctomeles dimolodontus), Bristol’s Panda is the most commonly
found small carnivoran found at the Gray Fossil Site. This suggests that these
animals had a relatively high population density, which is typical of small
mammals with versatile diets. For Bristol’s Panda, the menu would have included
various small animals and fruits, as well as eggs and insects, all of which are
typically abundant in forested habitats. With food sources available all year
round, Bristol’s Panda may have required small territories.
References
& Further Reading
Wallace
SC (2011). “Advanced Members of the Ailuridae (Lesser or Red Pandas – Subfamily
Ailurinae)”. pp 43-59 in AR Glatston (ed), Red Panda: Biology and Conservation
of the First Panda <Book>
Salesa
MJ, Anton M, Morales J (2005). “Evidence of a false thumb in a fossil carnivore
clarifies the evolution of pandas”. PNAS 130(2): 379-382 <Full article>
Wallace SC, Wang X (2004).
“Two new carnivores from an unusual late Tertiary forest biota in eastern North
America”. Nature 431: 556-559 <Full article>
Roberts MS & Gittleman JL
(1984). “Ailurus fulgens”. Mammalian
Species 222: 1-8 <Full article>
