Thursday, 26 November 2009

More social networking for pandas

Though olfaction is probably the most advanced of the panda’s senses, recent work on acoustic communication reveals just how important sounds are for successful social networking in a complex bamboo-based world.

A really thorough scrutiny of the acoustic structure of calls from individual pandas has just appeared in The Journal of the Acoustical Society of America and it shows them to be highly distinct. Furthermore, two particular features of a vocalization – its pitch and rapid variation in its volume – seem to be the factors that can best explain that distinctiveness. This computer-based analysis of panda acoustics also made a very interesting parting-shot. By comparing calls from related individuals, it appears as though certain acoustic features have a strongly heritable component. Vocal cues, suggested Ben Charlton and his co-workers in the abstract, “could be used as a measure of genetic relatedness.” I haven’t yet got to look at the entire paper, so I’m not sure whether they mean pandas, researchers or both might be using calls to assess relatedness.

OK, so there are fuzzy bits on graphs that humans can use to distinguish one panda from the next. But do pandas pay attention to these features of sound? In an experiment that mirrored one on olfaction carried out by Ronald Swaisgood and his colleagues more than a decade ago, Charlton and friends (including Swaisgood as a matter of fact) habituated female pandas at the Chengdu panda base to the recorded calls of a single male before switching to the bleats of another. The sudden increase in attentiveness on hearing the novel call demonstrates quite clearly that females are able to distinguish males on the basis of sound alone.

In a couple of follow-up experiments, the researchers manipulated aspects of the male vocalization to see what that did to females’ reactions. With the frequency normalized, females still perked up at the change from male A to male B but with volume variation under control they were not responsive to the switch. So volume variations seem crucial to the ability to distinguish between individuals. “Although giant panda bleats are low amplitude and features of amplitude modulation would be particularly susceptible to attenuation in the densely forested natural habitat that giant pandas inhabit…, these vocalizations could be used for close-range signalling of identity in direct encounters,” suggest Charlton and colleagues in Biology Letters.

A further paper, published in Animal Behaviour, revealed that there are clear differences in the bleats emitted by males and females, useful if you’re a solitary animal living in a dense bamboo forest. A male’s vocalization also appears to give an indication of his size and a female’s call appears to give away her age.

Next up. Panda vision.

Tuesday, 24 November 2009

Smelly pandas

I had a good day last Friday reading and writing about smelly pandas. From the earliest fieldwork on giant pandas during the 1970s and ’80s it was clear that these creatures have a complex system of olfactory communication. The “scent posts” that George Schaller and his Chinese colleagues discovered in the field in the Wolong National Nature Reserve appeared to be like “community bulletin boards” on which individual pandas would post all sorts of different messages, some of them alongside, some overlapping and some completely covering others.

A brilliant series of experiments on captive pandas at the China Conservation and Research Center for the Giant Panda in Wolong in the late 1990s began to reveal just how rich this olfactory world is. Males leave smells by urinating and marking using an anal gland and females leave smells mainly through urine alone, but another panda taking a sniff at these calling cards can probably work out the individual identity of the animal, its sex, reproductive status and get a feel for how far away it is.

In 2003, chemists identified almost 1000 different compounds in these panda secretions and excretions. Male markings contained much higher levels of short-chain fatty acids than did female markings, reported San Diego-based chemists Lee Hagey and Edith MacDonald in the Journal of Chemical Ecology. More than that, each individual had a pretty unique chemical signature such that given a sample at random, the researchers could, in the majority of cases, identify the individual it had come from. Though they needed a pretty sophisticated analytical tool to do this – gas chromatography-mass spectrometry – pandas have been living with these smells for many millions of years so one imagines have evolved the ability to make sense of them.

In a lovely bit of lateral thinking, Hagey and MacDonald then set about swabbing down a panda’s body to see if the mix of volatile chemicals varied from place to place. The resulting olfactory map is quite remarkable. I emailed Hagey to ask him a few questions about it and he very kindly gave permission for me to post it here (above). Basically, wherever the panda is black – on its four legs, its back, its ears and around its eyes – there is a complex mix of volatile chemicals.

“A panda’s forearms, legs and back don’t carry many smelly messages,” Hagey informed me, denoted by yellow in his map. Their ears, however, are heavily scented with urine, as are the undersides of their forepaws, which presumably act to ferry the stuff from their genitals to their ears (orange). Intriguingly, the black rings around a panda’s eyes, which get rubbed a lot, have a completely unique smell and are completely free of urine (turquoise). This is achieved by the panda being careful to use the back of a paw rather than the urine-scented underside (also turquoise). The dark blue represents the odour from the anal glad, which has been daubed on a nearby tree.

“The body of the giant panda is shown to be a kaleidoscope of scent patches and zones, each with a unique chemical makeup,” Hagey and MacDonald wrote in Giant Pandas: Biology and Conservation. They went on to propose that the urine scented ears act like miniature beacons, allowing these secretive smells to be caught by and spread on the wind.

I love this, though I’m only left wanting to know more. As far as I can tell nobody has yet had a go at manipulating this kaleidoscope to see how it works.

Image © Lee Hagey.

Wednesday, 18 November 2009

Selling compromise in conservation

This, I’m guessing, is rather hard. At the Linnean Society of London yesterday, I was one of (as it turned out) seven guest speakers at a day-long symposium about Galapagos. One of the presentations in particular stood out for me – that by Mark Gardener (below) of the Charles Darwin Foundation (CDF) in Galapagos.

His field of expertise is invasive plants, of which there are now around 700 in Galapagos. In his talk, Gardener laid out some stark figures: between 2001 and 2007, CDF carried out 29 plant eradication projects, covering 23 different invasive species and mostly focused on those still limited to a small area. Only four of these succeeded in their eradication goal and none of them involved areas greater than 1 hectare. His message was basically that eradicating plants is a practical impossibility.

It was not one that went down well with the well-healed London-based audience, or at least that was how I saw it. The dream of transforming these still relatively pristine islands back to a pre-human-like state is one that’s hard to give up. Without this rather straight-forward restoration ideal, it’s much harder to know what conservation means.

Gardener had a few ideas. He talked about “transformers”, those invasive plants that seem able to dominate the landscape and in so doing radically alter the availability of resources, the trophic structure and productivity. Understanding such species would be key.

Instead of removing them though – an impossible task for established transformers like the guava Psidium guajava - Gardener envisages “the maintenance of resilient novel or hybrid ecosystems rather than trying to return systems to their pre-Darwin state.” These novel ecosystems then would be “composed of mixtures of native and exotic elements that would never have occurred naturally” and would “concentrate on ecosystem function instead of iconic species.”

It sounded like a lot of sense to me, but ironically I imagine a compromise like this - which has a fair chance of succeeding – is harder to sell to the public and hence funding agencies than a purist ideal that has no hope in Hades of working.

Wednesday, 11 November 2009

Galapagos at the Linnean Society

Next week I have the privilege of speaking in the meeting room of the Linnean Society of London in Burlington House, Piccadilly. It is, of course, the same place in which the papers on natural selection by Charles Darwin and Alfred Russel Wallace were read out in May 1858.

The day-long event is entitled The Galapagos Archipelago: A living laboratory and has been organised by Sandy Knapp, a botanist at the Natural History Museum, and Sarah Darwin and it’s a privilege to be included as one of the eight “highly respected speakers”.

I’ll be talking about tortoises and the title for my presentation is “The Galapagos tortoise: an evolutionary journey”. This is going to touch on several of things: there’ll be a dose of Galapagos history (in which early visitors came, saw and ate tortoise); I’ll cover the early tortoise conservation successes from the 1960s onwards; the very exciting genetic research that has really improved what we know about these creatures; and of course the very important flagship role they play. Lonesome George will probably get a mention.

It will be very nice to hear the other talks (see here for the full programme) and in particular to meet several people. I have not met Danish botanist Ole Hamann, but interviewed him for my book on Lonesome George and he very kindly let me use some of his photographs. He happened to turn up on George’s island Pinta just after the tortoise was discovered in 1972 and he took some great photos of him just before he (George) got taken off to Santa Cruz.

Paquita Hoeck is also speaking. She is doing some great genetic work on the Floreana Mockingbird, which has required extracting DNA from the individual bird that Darwin shot on the island 180-odd years ago. Her father Hendrik Hoeck is a former director of the Charles Darwin Foundation and Paquita, now at the University of Zurich in Switzerland, spent her early years in Galapagos.

So whilst I crack on with my panda book, I am also writing my talk for the Linnean Society meeting, giving me the weekend to get it slick.

Monday, 9 November 2009

Fictional facts

Last week, I received a copy of a new panda publication - 100 Facts About Pandas by Claudia O’Doherty, David O’Doherty and Mike Ahern.

It is an extraordinary little book. It has no introduction, no preface, no prologue, no epilogue and draws no conclusion. It is a couple of hundred pages – a double-page spread for each “fact”. These play off just one joke: pandas.

According to its product description on Amazon, 100 Facts “chronicles for the very first time the amazing social, cultural and natural history of the panda, fully illustrated with photographic evidence, drawings and scientific diagrams and shocking case-studies.” That sounds a little like the blurb I might have put on my book. The difference is that 100 Facts About Pandas is completely devoid of facts about pandas. Not one.

Instead, Irish comedian David O’Doherty and his coauthors’ “facts” play around established scientific truths, historical figures or past events that have little or nothing to do with the giant panda. These in themselves are not funny, but the surprise insertion of a panda or two is remarkably effective at triggering a guffaw. I’m not sure another creature could sustain this format so successfully for so long, but the panda manages it.

O’Doherty and his co-authors will no doubt be amused that I struggled with their flamboyant disregard for fact. Take Fact 34, for example: “Owing to a bureaucratic mix up in registration by naturalist Dr Joseph Banks in 1831, the panda bear is officially classified not as a mammal, but as a nut.” The panda then appears in a rather pretty woodcut engraving alongside a shelled walnut.

Surprisingly, I was fine with the panda being a nut, but had a problem with the idea that species might get “registered”, that Banks had a doctorate (‘cos I don’t think he did) and that he could have carried out this taxonomic miscarriage from beyond the grave (he died in 1820).

It’s a cheerful stocking-filler, but it’s not for non-fiction nerds like me.

Wednesday, 4 November 2009

The afterlife of animals

I have been busy this week reworking one of my chapters into a paper for an academic workshop that’ll take place at the University of Manchester in December.

The meeting – The Afterlife of Animals – has been organised by historian of museums Sam Alberti, who is “seeking to promote a wider understanding of the preservation and provenances of specimens and to suggest new ways to develop collections as both natural and cultural heritage.” It was a somewhat daunting honour for me – a writer rather than a bona fide academic – to contribute a paper on what happened to Chi-Chi the giant panda after her death in 1972.

This, in Sam’s words circulated to the dozen-or-so contributors, is the premise of the project.

Animals travel through sites for display in the modern world, acquiring meanings as they go. It is the contention of these papers that this accrual continues post-mortem; that they are mobile, flexible entities in death as they were in life. Animals and their remains connect museums and the menagerie, the exhibition and the wild. They were and are at once natural and cultural, the material embodiment of what historians of science dub ‘knowledge in transit’.

Sam has divided the workshop into five sessions – primates, hunter/hunted, behemoths, personalities and pachyderms. There will be two papers in each and my contribution on Chi-Chi will appear in the “personality” session along a paper by Manchester historian of natural history Chris Plumb who will reveal everything about “The Queen’s Ass” (a zebra gifted to King George III’s wife Charlotte as a belated wedding present, which took Georgian London by storm). It’s going to be great and is expected to result in an edited book.

What with tidying up this paper, writing a new epilogue for a reprint of Lonesome George and half-term, I didn’t quite make my rather woolly target of two more chapters to my editor by the end of October. I have one of them ready (on Armand David and the discovery of the giant panda), the second is close and am on the way with several more.