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Background information on the question: “Do Pandas Really Exist? “ There are two animals that are called “pandas”, the giant panda (Ailuropoda melanoleuca) and the red (or lesser) panda (Ailurus fulgens). In 1825, Frederick Cuvier first described the red panda for western science. The giant panda was discovered and described in 1869 by Père David. Figure 2. Ailurus fulgens. From ARKive.org (2004). Figure 1. Ailuropoda melanoleuca. From baldeagleinfo.com (2005) When scientists discover and describe a new species, the first thing they do is give it a two-part scientific name and try to classify it into a group of its closest relatives. However, soon after these two species were discovered, scientists argued about what a panda is. Some scientists thought that both pandas are most closely related to members of the raccoon family (option 1). Others thought that the red panda is part of the raccoon family and the giant panda is part of the bear family (option 2). And yet others thought that the two pandas belonged together in a separate panda family (option 3). When this controversy started, scientists were limited in the type of information they could use to answer this type of question. Because they didn’t yet know much about proteins and DNA, they certainly could not use them to help answer these questions. Therefore, they had to rely on other types of information like biogeography (where organisms live), fossils, behavior, and morphology (how the animals are built). Here is some of the information they had to work with: Figure 3. Example members of the raccoon family (procyonidae): the northern raccoon(NPS.gov, 2004) and the coatimundi (Braddy, S. 2003). Figure 4. Example members of the bear family (ursidae): the sun bear (Bies, 2002) and the grizzly bear (Ballenger and Dewey,2002). ? ? Figure 5. Giant (baldeagleinfo.com, 2005) and red pandas (ARKive.org, 2004) Biogeography. Both of these animals live in China’s southwestern bamboo forests (Figures 6 and 7). The six bear species are found in Europe, Asia, and the New World (Figure 8). Except for the red panda, all of the other members of the raccoon family live in the New World (the Americas)(Figure 9). (Distribution maps based on Nowak, 1991.) Figure 6. Giant Panda range Ailuropoda melanoleuca Figure 7. Red Panda range Ailurus fulgens Figure 8. Worldwide bear (ursidae) distributions. Figure 9. Worldwide raccoon family (procyonid) distribution Fossils. Fossil raccoons first appear in North America and spread to Asia and Europe about 20 million years ago. Panda fossils (from about 12 million years ago) first appeared in Europe and North America. They are similar to a group of small bear fossils (that are all now extinct). Figure 10. Movement of the continents over time (CDSP, 2003) Behavior. The red panda feeds on bamboo sprouts, other plant material, and the occasional small animal. The giant panda feeds mostly on bamboo, but also eats other vegetation and occasionally hunts fish and small mammals. Unlike bears, the giant panda marks its territory using scent glands something that the red panda and the members of the raccoon family also do (Nowak, 1991). Morphology. Like other bears, the giant panda gives birth to very tiny offspring that grow into very large adults. The adult bears are 100s of times larger than the newborns. On the other hand, the red panda and members of the raccoon family give birth to newborns that are about 50 times smaller than the adults (Nowak, 1991). Both species have skulls, teeth, and forepaws that are specially adapted to eating bamboo. The table below presents information on the weights, skull lengths and dental formulas for some representative members of the raccoon and bear families and the two panda species. Table 1. Morphological characteristics. Species Family Raccoon (Procyon lotor) Raccoon Weight (kg) (Nowak, 1991). 6 Coatimundi (Nasua narica) Raccoon 4.5 13 Grizzly Bear (Ursus arctos) Bear 450 49.5 Sun Bear (Ursus malayanus) Bear 46 22 Red Panda (Ailurus fulgens) ? 5 11.5 Giant Panda (Ailuropoda melanoleuca) ? 100 26.5 Additionally, the giant panda has a wrist bone that sticks out like a thumb to help it grip the bamboo. This wrist bone (sometimes called a pandas “thumb”) is used to strip the leaves off of the bamboo (Morris and Morris, 2000). That way, the panda is left with only the nutritious bamboo shoot. Skull Length (cm) skullsunlimited.com (2005) 12 Figure 11. Sesamoid bone of the giant panda (Morris and Morris, 2000). Dental Formula skullsunlimited.com (2005) I 3 1 4 2 C P M = x 2 =40 3 1 4 2 I 3 1 4 2 C P M = x 2 =40 3 1 4 2 I 3 1 4 2 C P M = x 2 =42 3 1 4 3 I 3 1 4 2 C P M = x 2 =42 3 1 4 3 I 3 1 3 2 C P M = x 2 =38 3 1 4 2 I 3 1 4 2 C P M = x 2 =42 3 1 4 3 Figure 12. Comparison of the sesamoid bones of a grizzly anda a giant panda (Morris and Morris, 2000).