The giant panda has long been the poster child for the ‘suicidal species’; spend any time working in panda conservation with the public and you will be asked, usually once a month, why they behave as though they want to become extinct. While the mere idea of a species intent on its own extinction is abhorrent to any scientist, the fact is that pandas have been dying, quite successfully, for a very long time indeed.
The Reluctant Bear
Pandas have existed for around 8 million years, living and dying during all that time. These days, most of the pubic focus on pandas is not how they die, but how they, allegedly, fail to breed. Much of their bad reputation comes from the idea that it has been notoriously difficult to get pandas to make babies in captivity.
The first pandas appeared in zoos in the 1950’s, however it wasn’t until the early 1990’s that zoo scientists decided that they should co-ordinate their knowledge, and make a concerted effort and try to learn what pandas want and need in order to breed successfully. Forty years of practically no captive breeding had essentially ingrained the idea, in the public mind, that pandas were bad at making babies. In actual fact, it is often notoriously hard to breed almost any species in captivity, but pandas – being famous – seem to bear the brunt of the bad reputation. Today, as a result of these recent, focused efforts, there are now around 400 captive bred pandas in the world. the. When you consider that there are only about 1864 giant pandas in the wild, that’s a pretty impressive captive breeding achievement. To put it another way, if you have ever seen a real live giant panda, chances are you have seen panda that has been bred in captivity.
However, captive breeding of giant pandas is still fraught with uncertainty. This is due to a low birth rate, a narrow window for conception to occur, and sometimes even just the fact that ‘mummy’ and ‘daddy’ panda don’t like each other (though, like all relationships, this can change on a yearly basis). On top of everything else, even when a female does get pregnant, this doesn’t automatically mean that she will give birth. A team led by Erin Willis, at the Memphis Zoological Society, studied the pregnancies of four giant pandas across zoos in the US and their findings confirm the idea that, in captivity at least, giant panda mothers are very prone to losing their cubs before birth.
Given the above, it is perhaps understandable why some people think that the panda is determined to make itself extinct, but let’s put the facts into context. For instance, a low birth rate is not the same as a bad birth rate; pandas might not pop out hundreds of babies in their lifetime, but neither is a lack of babies the reason for their declining numbers. Giant pandas give birth, on average, every 2-3 years. That means that they are more than capable of maintaining and growing their population; they just don’t do it as fast as, say, humans or bacteria. And while a three day window, once a year, might not sound like much of an opportunity for babies, this is the roughly the same chance to get pregnant that your average sheep has; many animals only have several days (or hours) in the year during which they can become pregnant.
Trouble in the Mountains
As with most endangered species, habitat loss is the primary driving force behind the giant panda’s endangered status. Where the giant panda’s range once covered much of South and East China, today it is restricted to a fragmented range, approximately 30,000km2 in total size, along the Sichuan Mountains of China, at the edge of the Plateau of Tibet.
While an area the size of Belgium might sound like plenty of room for an endangered bear to get busy, the truth is that all that valuable bamboo forest is scattered across five different mountain ranges and the pandas themselves are divided up into around fourteen different, isolated groups (see Figure 1: Where to Find Pandas in China). Furthermore, a study carried out by the ITC Natural Resource Department in the Netherlands, in conjunction with the Foping Nature Reserve in China, found that within the available bamboo forest habitat, giant pandas are quite picky about where they will live – it needs to have the right type of bamboo, at the right altitude, with the right landscape.
The effects of all this fragmentation are most significant during breeding season. Male pandas can spend over a week wandering the forest, looking to find a female during her 3 ‘magic days of conception’. If there are no barriers in the way, a lucky male can find up to 9 different females to mate with. However, the fragmentation of the habitat can mean that some males may find only 4 females; that means less than half the number of pandas being born in the wild.
In the very isolated populations, genetic inbreeding – e.g. cousins breeding with cousins, fathers with daughters – can lead to severe and even fatal deformities in the young cubs; one might say that, in those cases, the pandas are breeding themselves into extinction. Fortunately, such cases are rare in the wild, but inbreeding is also a worry for those in charge of the captive panda population. In fact, one study, that included scientific input from the Chengdu Research Base of Giant Panda Breeding, concluded that, while well managed, the current captive population could do with an injection of wild panda genes to prevent any long term ill effects.
Trouble in the Forests
Even in a suitable area of bamboo forest with an appropriate selection of mating partners nearby, the problems of the giant panda are far from over. In a study that looked at cause of death for almost 800 wild pandas over a period of 35 years – including data from many previously unavailable sources – Jin-Shou Zhang and colleagues, from the Chinese Academy of Science, discovered that the main causes of panda demise have changed several times over the last few decades (see Figure 2: Changing times and changing causes of death in wild pandas).
From the 1970’s through to the mid 1980’s, starvation was the sole cause of death in the wild pandas studied. This is perhaps not surprising as it was during this time that a mass flowering and subsequent die-off of bamboo occurred. Bamboo is an unusual plant in that every member of a species will simultaneously flower and then die off in an area. While the time between these die-offs can be decades long, if you happen to be an animal that feeds almost exclusively on said plant, the outcome can be understandably disastrous.
The impact of the food shortage for the pandas was compounded by the already mentioned fragmented nature of its existing bamboo forest habitat. Giant pandas are known to eat 25 different species of bamboo. However, bamboo has very little energy, which is why pandas spend most of their waking hours eating as much as 40 kg per day, and then sleeping up to 16 hours a day digesting it. In the past, a bamboo die-off simply meant moving to an area where there was another edible species, but when you’re limited to a small pocket of forest up in the mountains that isn’t really an option, plus they don’t really have the energy to walk for miles in search of food. The result is thin, hungry, dead pandas.
Having made it through the lean 1970’s and 1980’s, the distinctive fur of the black and white bear proved to be its next downfall. If there’s one thing humans like doing, it’s killing animals to sell their bits. Poaching accounted for almost 90% of the recorded panda deaths between 1986 and 2000, with the only respite from hunting coming following the passing of strict laws against panda hunting. Today, hunting pandas is punishable by death.
The only good news during these times came from the fact that, following the bamboo famine of the previous decades, some pandas were actually living long enough to die of old age.
The Unexpected Threat
Having survived (to an extent) home destruction, starvation, and hunting, another threat recently became apparent to the survival of the giant panda. Nobody wants to think of the cute and cuddly panda as a parasite infested wild animal – certainly not those responsible for the marketing of panda merchandise – but, Zhang and his colleagues have shown that this is indeed the case. Since the early 1990’s, death due to infection from roundworm parasites has grown to become the biggest cause of death in wild pandas today; the larvae of the parasites burrow through the internal organs of the infected panda with inevitably serious consequences.
In a perfect example of the complexity of the natural world, the increase in panda deaths from parasite infection is thought to be a direct effect of the habitat loss and fragmentation that made the species endangered in the first place. Less space to live means more pandas living closer together, which means they are more likely to pass on parasites and diseases to each other. As Zhang reports, between the mid 1970’s to the mid 1980’s, the density of pandas in the average bamboo forest increased by around 400%; this time-scale that coincides with the increase in parasite related deaths.
How to Kill a Panda
The giant panda is not cuddly, lazy, or bad at making panda babies. It is a parasite infested, smelly, wild animal that has been the victim of habitat destruction and hunting; except for the hunting, that’s actually okay. At the simplest level, if you want to kill a panda you limit its living space. This is exactly what we, as a human society, have done.
We know how to kill pandas, and we are very good at it. We are also, fortunately, getting better at learning how to save them. If we are lucky, we might be able to use the knowledge we gain doing that to save many other species, including ourselves, from a similar fate.
About the Author
The author has worked alongside pandas for two years and continues to enthusiastically praise their virtues to any visitors who will listen to him.
He has no plans to kill any pandas.
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