Red Panda: The Fire Cat
by Miles Roberts (Photos by Jessie Cohen/NZP)
The first known written record of the red panda occurs in a 13th-century Chou dynasty scroll. But it wasn’t until some six centuries later that red pandas became known to Europeans. And Major General Thomas Hardwicke’s 1821 presentation of "Description of a New Genus... from the Himalaya Chain of Hills between Nepaul (sic) and the Snowy Mountains" to the esteemed Linnaean Society of London is regarded as the moment the red panda became a bona fide species in Western science. Hardwicke called the animal "Wha" because "It is frequently discovered by its loud cry or call, resembling the word ‘Wha,’ often repeating the same..." He also mentioned several other local names, including "poonya," which was eventually anglicized to "panda."
It may be poetic justice that Hardwicke received only partial credit for his "find." Hardwicke was delayed in returning to England from India with his specimens and, under the rules of taxonomic nomenclatural priority, was scooped by the ubiquitous French naturalist Frederic Cuvier, who gave the Wha its official scientific name: Ailurus fulgens, the "fire-colored cat." Perhaps we should be grateful the aristocratic Cuvier crossed the finish line first. He provided an elegant Latin name, christened Hardwicke’s Wha "the Bright Panda," and described it as "a beautiful species, one of the handsomest of known quadrupeds." However, British scientists saw it otherwise. They were incensed that Cuvier would "prevent England’s reaping the zoological harvest of her own domains," as irate British naturalist Brian Hodgson sputtered in 1847.
For almost five decades, Ailurus fulgens was the panda. Then, in 1869, a large black and white bearlike animal with teeth and diet remarkably similar to those of the Wha was discovered in China by Pere Armand David, a French missionary. This animal was dubbed "giant panda." Instantly, Ailurus fulgens became the "lesser" panda, a pejorative name that has been all but dropped in favor of the more apt and dignified red panda. In retrospect, the application of the same name to both species was prematurely based on superficial anatomical similarities and only fueled the controversy about how closely related these two species really are. Today scientists are still struggling to untangle the taxonomic knot that these unfortunate baptisms helped create.
After Hardwicke and Cuvier, only scant information about the red panda’s biology was forthcoming. Then the events of 1869 turned the panda spotlight squarely on the giants and very little of substance about the red pandas came to light for more than a century. But in the last 20 years, important new information has rapidly accumulated about red pandas from field and zoo studies, largely as result of work at the National Zoological Park, supported by Friends of the National Zoo and the Smithsonian Institution. Although far from complete, the picture of the red panda we have today gives us a reasonable idea of what this rare and beautiful species is all about and what we must do to preserve it.
Red pandas live only in temperate forests in the Himalayan foothills from western Nepal through northern Burma and in the mountains of southwestern China (Sichuan, Yunnan, and Xizang provinces) at altitudes between 4,900 and 13,000 feet. Their habitat occupies a cool montane/subalpine zone with little annual fluctuation in temperature. Seasonal monsoons, trapped by southern ranges and slopes, support a mixed forest of fir, deciduous hardwoods, and rhododendrons, with a bamboo understory on which red pandas depend. Thus, while the arc of the red panda’s distribution extends thousands of miles, from Kashmir in the west to northern Sichuan in the east, their requisite habitat lies in a very narrow and fragile ecological band.
The red panda’s diet specialization is very unusual in mammals. Only giant pandas, two bamboo rats (one in China and another in Brazil), and a small lemur in Madagascar are obligate bamboo eaters. Bamboo eating is apparently an ancient adaptation in this species. Red pandalike fossils, complete with the massive dentition and robust skulls necessary for attachment of powerful chewing muscles, have been found in Miocene (25 to 5 million years ago) deposits of eastern Europe and Pliocene (5 to 2 million years ago) strata of western North America. Other paleontological evidence suggests that the distribution of both bamboo and red pandalike animals has expanded and contracted in response to macroclimatic temperature and moisture oscillations.
Their range expands during warm, moist periods and contract during cool, dry ones. Today’s distribution, with bamboo and red pandas confined to small, isolated refugia, appears to be a mere remnant of a much more widespread one in the past.
The red panda’s ancient dietary specialization on bamboo has had dramatic consequences for the rest of its biology. In essence, bamboos are giant grasses that have evolved woody stems and tough, leathery leaves to deter predation. Because they are so high in indigestible fiber and are loaded with abrasive siliceaus compounds, bamboos are difficult to eat and to digest. Many mammalian herbivores, such as cows and horses, that eat grasslike plants, have evolved extra-robust teeth and special fermentation chambers in their gut to help them get as much energy as possible from their food. While the red panda does have massive teeth for crushing bamboo leaves, its gut is unspecialized. Karen Fulton, a colleague working at the National Zoological Park, found the gut retention time of bamboo in red pandas is a speedy six hours and only about 25 percent of the already limited energy is extracted from the bamboo. She also found that red pandas eating only mature bamboo leaves, which would be typical for an adult in the wild from late autumn through early spring, could barely maintain their body weight. Some even lose as much as 15 percent of their body weight on this diet.
Clearly, red pandas are on a tight energy budget for much of the year. Not surprisingly, they have several strategies to help make energetic ends meet. Pralad Yonzon, working in Nepal, and Ken Johnson, George Schaller, and Hu Jinchu, working in China, found that red pandas spend as much as 13 hours a day searching for and eating bamboo. In contrast to the giant panda, which Johnson’s team also studied, red pandas are very selective about what part of the bamboo plant they eat. The red panda selects only the tenderest young leaves and shoots and thoroughly chews each mouthful to increase digestibility. Giant pandas eat virtually every part of the bamboo plant except the roots and barely chew at all.
Brian McNab, a physiological ecologist working with National Zoo animals, discovered that to cope with a low-energy diet and cool environmental temperatures, red pandas have evolved an extraordinarily low metabolic rate, expending almost as little energy as a sloth. They also are able to temporarily lower their metabolic rate even more at very cold temperatures. These physiological adaptations, combined with dense fur covering the entire body (including the soles of the feet) and behaviors to regulate temperature (such as curling up into a tight ball when it’s cold), serve to conserve body heat and energy expenditure.
A tight energy budget driven by the reliance on low-energy food also influences reproduction in the red panda. Reproduction is energetically expensive, so red pandas reproduce in the late spring and summer when tender, more digestible bamboo shoots and new leaves are available and temperatures are warmer. John Gittleman and I, working with the National Zoo’s red panda collection, found that although food energy is more available during gestation and lactation, red pandas still produce small litters, averaging just two cubs each. And, at 135 days, the red panda has an extraordinarily long gestation period
for an animal of its body size. We also found that even though lactating mothers eat as much as they can as fast as they can, young grow and advance to sexual maturity slowly. Young reach adult size at about 12 months of age, sexual maturity at about 18 months. These conservative features of reproduction and growth add up to a very sluggish rate of reproduction and consequently very slow recovery from population declines.
The bamboo diet also influences red panda social behavior. Because the young grow so slowly, the association between a mother and her offspring is extended, lasting over a year. Pralad Yonzon believes the mother-young association is the only form of gregarious behavior in red pandas except for an ephemeral mating consortship during the brief breeding season
. Otherwise, red pandas are quite solitary.
Red panda ranging patterns are similar to those found in most Carnivora species on large, overlapping home ranges where they rarely meet one another. At first this seems somewhat counterintuitive for an animal feeding on something as abundant as bamboo. But because red pandas selectively feed on the tenderest shoots and leaves, usable resources are probably sparsely and patchily distributed in the habitat, much like the vertebrate prey of cats. Overcrowding and overuse of resources may be reduced by the dispersed social system.
Yonzon and Johnson and his colleagues found that female red panda home ranges average about one square mile, while male ranges are about twice that size - exceptionally large for an animal weighing only about 11 pounds. However, in keeping with the energy conservation strategy so paramount for survival in this species, individuals traversed their home ranges at the rate of only about 650 to 1,000 feet per day and used only about 25 percent of the total home-range area per month.
In a pattern typical of many other carnivores, male home ranges generally overlap those of more than one female and may even expand in the mating season. My studies at the zoo show that individuals scent mark their territories and home ranges with urine and with secretions from anal glands and glands on the soles of their feet. They also use regular latrine sites. These "scent posts" communicate information that helps maintain social spacing and undoubtedly convey information about the sex, age and reproductive condition of the depositor. Gustav Peters and I, again working with the Zoo collection, showed that red pandas use subtle body language, including head bobs and tail arching, and vocalization, including a threatening "huff-quack," an alluring "twitter," and a warning "whistle," to communicate at close range.
Recent field studies also provided vital new information about the red panda’s tenuous status in the wild. Prime red panda habitat is very similar in appearance and composition to the old-growth forests of our Pacific Northwest, and the consequences of disturbance are quite similar. A high canopy, composed of various species of conifers, most notably fir and hemlock, mixed with deciduous hardwoods, such as oak, chestnut, and maple, provides protection for a stable understory of rhododendron and bamboo. Clouds enshroud these forests for much of the year, promoting extensive growth of mosses and lichens on every possible surface. The densely packed intertwining root systems of this large amount of vegetation binds the soil on even the steepest slopes to maximize moisture retention and slow water runoff.
In recent years, however, this stable system has been profoundly disturbed by increasing human populations. People are logging the forests for building material and fuel, and their domestic animals consume understory plants and compact fragile montane soils. Even minor disturbance in this fragile habitat, such as clearing a small patch for agriculture, can initiate a familiar and devastating chain reaction: The impact of heavy seasonal rains falling through the canopy damages the soil and loss of interlacing root systems promotes soil erosion and rapid water runoff, which extends to downslope areas not yet directly disturbed. During the rainy season, brooks and streams become raging torrents that carry away precious mountain soils to distant plains.
Little of the remaining red panda habitat, even that in national parks and wildlife reserves, is spared this relentless degradation. For example, the 660- square-mile Langtang National Park in Nepal is believed to be that country’s largest bastion for red pandas. But 30,000 people also depend on resources within the park for their livelihood. These people strip and cut trees for building materials, forage for livestock, and fuel for cooking, tourism, and cheese production. Not only do these activities eliminate food, shelter and nesting areas for red pandas, and other wildlife, but hunting and the depredations of feral dogs also take a considerable toll on the red panda population. We suspect the same scenario is being played out elsewhere in the red panda’s range. Zoos have taken a special interest in the study and conservation of red pandas. At present (1992), about 85 zoos in the world hold more than 300 red pandas and in the last two decades more than 300 have been born in zoos, many of them at the National Zoo. Virtually all zoos with red pandas participate in management programs designed to ensure that a viable zoo population survives for the foreseeable future. For example, the red panda population in North American zoos is managed under the Red Panda Species Survival Program (SSP) of the American Association of Zoological Parks and Aquariums (AAZPA). This program, which I coordinate, maintains a studbook of all red pandas in North America, uses genetic and demographic management analyses to determine which animals should be mated, and develops long-term management and research strategies for the species. Similar programs have emerged in Japan, Europe, Australia, and China. Recently, the International Red Panda Management Group (IRPMG) was formed to coordinate these regional programs and integrate them with the conservation efforts of governmental and nongovernmental agencies around the world.
This sort of global conservation effort, linking the international zoo, academic, wildlife management, and political communities, requires an enormous amount of time, energy, and money from many sources. But our efforts seem to be paying a modest dividend. At the International Giant Panda and Red Panda Conservation Workshop held in Washington in June 1991, biologists from 14 countries met to review red panda status and biology and to forge a strategy for integrating field and zoo-based research and conservation efforts. Several priority projects identified at this workshop are now underway. Field studies in Nepal, Bhutan, Sikkim, and Sichuan are examining the exact status and quality for remaining red panda habitats and the nature of the human-environment-animal interactions occurring in them. Other studies are assessing the levels and rate of loss of genetic variation in wild populations, and zoo and wildlife biologists native to countries where red pandas are found are being trained in the research, management, and husbandry techniques necessary to preserve wild and zoo populations. To borrow a couple of terms from Cuvier, we hope that these and other measures will help create a bright and shining future for the red panda.
Miles Roberts is Deputy Head of the Zoo’s Department of Zoological Research.
(ZooGoer 21(2) 1992. Copyright 1992Friends of the National Zoo. All rights reserved.)