Thanks to Tet Zoo, I sometimes receive books to review, and earlier on in the year I was fortunate enough to receive a copy of Lewis Smith’s Why the Lion Grew Its Mane (Papadakis, 2008). Smith is a science reporter at The Times and in this book, billed as presenting ‘a miscellany of recent scientific discoveries from astronomy to zoology’, he takes us on a tour of some of the newest, neatest science. Despite its title, Why the Lion Grew Its Mane isn’t just about animals, but also includes sections on cutting-edge technology, astronomy, genetics and psychology. I don’t know enough about any of those subjects to comment on them, so what you’re going to get here is a review of only some of the book – namely, of course, the parts on tetrapods.
Basically what we have here is a hand-picked selection of newish science stories that are cool, involving charismatic or neat subjects. This means, I suppose, that coverage is biased towards dinosaurs, big cats, meerkats and so on, and if you keep an eye on new and breaking news, many of these discoveries will already be known to you: they’re exactly the sort of things that get picked up by National Geographic, BBC science news, and the broadsheet newspapers. Think parthenogenesis in Komodo dragons, dinosaurs found in burrows, the Spanish mega-sauropod Turiasaurus, spear manufacture in chimpanzees, orangutan bipedality, Tiktaalik, the incredible tongue of the Tube-lipped nectar bat Anoura fistulata, evolution in action among Darwin’s finches and Bahaman anoles, and the development of new songs in urban passerines. Here they are – together – bound up in a glossy, very attractive, large format, ‘coffee table’ book. Excellent photos appear throughout and the book really is a joy to look at. The volume is in fact so attractive that I tried hard not to be nasty about it, but read on.
The book takes its name from the section on baldness, virility, and mane size in lions Panthera leo. Lions are variable in mane size and extent, with males of some populations lacking manes entirely, and why lions have manes, and why manes are so variable, remain two of most debated questions in felid biology. Following research by Julian Kerbis Peterhans and colleagues, Smith states that fully-maned lions may in fact be ‘beyond their prime’ and that individuals with less-developed manes may be more attractive to females. He also notes that mane extent varies with climate, with lions from the hottest, most humid places having the thinnest manes. This is – based on what’s been published – partly right, but it’s also partly very wrong.
I presume that the research discussed by Smith is that eventually published by Gnoske, Celesia and Kerbis Peterhans (Gnoske et al. (2006) [as discussed below, sources are not cited in the book], but what’s confusing is that Gnoske et al. (2006) didn’t really say what Smith ascribes to Kerbis Peterhans. Concentrating on the (sometimes maneless) male lions of the Tsavo region [one shown here, from wikipedia], Gnoske et al. (2006) showed how mane development is not fully associated with sexual maturity (in other words, that mane development is extensively delayed in some populations), and that ‘climatic adaptations to the relatively hot and humid climate of GTE [greater Tsavo ecosystem] has resulted in changes that may slow down and delay the onset of mane development and growth. The slower development of the mane and the smaller mane surface should, in theory, improve the potential for maintaining efficient thermoregulation’ (p. 558) [on thermoregulation, see the thermographic image below, from wikipedia. The mane clearly has an insulative effect]. Kays & Patterson (2002) had previously argued that the sometimes maneless lions of the Tsavo region owed their sparse or absent manes to local environmental conditions (like the area’s abundant thorn bush and hot, dry climate), Patterson (2004) proposed that particularly high levels of testosterone (itself associated with a social system where a pride contains but a single male, rather than a coalition) resulted in the reduced/absent manes of the Tsavo region, and Patterson et al. (2006) later showed how up to 50% of the variation seen in mane length and density was correlated with climate.
Why manes are so variable is clearly a complex subject and there are several competing views; you might have recognised that none of this really tells you ‘Why the lion grew its mane’. I recognise that – given the short, snappy text and need to summarise – Smith was not able to indulge in complex, detailed discussions of the subjects he covered. Nevertheless, as demonstrated by the section on lions, I was left throughout the book with the impression that Smith had based his text on recent reports alone, and as a result his text merely presents one, recently mooted opinion on any given subject. Furthermore, his text often seems naοve in that it doesn’t seem informed by the work that has gone before.
One section that will perhaps be of greatest interest to readers here is that on new species, and by now I suppose that most of the stories covered in this section will be highly familiar: Smith looks at the resurrection of the Sundaland clouded leopard Neofelis diardi (or diardii) (covered on Tet Zoo here), at the discovery of the Kipunji Rungwecebus kipunji (covered on Tet Zoo ver 1 here) and at the naming of the Cypriot mouse Mus cypriacus. Ah, the Cypriot mouse. Smith doesn’t really repeat that most-disliked of statements (you know, the one claiming that the mouse was ‘Europe’s first new mammal in 100 years’), but he does at least allude to this idea, stating that discoveries of new mammals ‘almost always [occur] in remote regions of the world such as South American rainforests’, and ‘Europe has been well trawled by naturalists over the centuries, making it hard to believe than anything as big as a mouse remained undiscovered’. Long-time readers of Tet Zoo will recall my mild annoyance at claims such as these when they were first mooted in the popular press back in 2006. In reality, even boring old, well-explored, no-new-species-to-reveal Europe yielded 32 new mammal species between 1906 and 2006.
Smith also writes about DNA barcoding of North American birds, and I was particularly interested in the discussion of white-headed gull taxonomy as a two-page photo-spread declares in giant writing that ‘Over the centuries, eight gulls had been identified as separate species. Yet when they were assessed, their genes were found to be virtually the same’ (pp. 96-97). Smith also says that ‘one type of gull … had been categorised as eight different species’ (p. 95) and that these eight ‘should all be classified as the same bird or at the very least only as subspecies, according to their DNA’ (p. 95). The eight species concerned are the California gull Larus californicus, Herring gull L. argentatus [photo below by Neil Phillips], Thayer’s gull L. thayeri, Iceland gull L. glaucoides, Lesser black-backed gull L. fuscus, Western gull L. occidentalis, Glacous-winged winged L. glaucescens and Glaucous gull L. hyperboreus. Hold on – who says that they should be regarded as the same species?
We all know that the taxonomy and phylogeny of the white-headed gulls is very complex and very confusing – there are multiple populations that grade into one another [though forget the ‘ring species’ concept*] and multiple views on whether populations should be regarded as subspecies or species – but I was not aware of any recent article which had promoted such a massive act of lumping. If anything, ornithologists have taken to splitting up the white-headed gulls even further: as recently as 2007 it was being recommended that, based on mtDNA data (Crochet et al. 2002, Olsen & Larsson 2004, Pons et al. 2005), certain ‘subspecies’ of L. argentatus should be elevated back to specific level (namely L. smithsonianus, originally named as a distinct species in 1862 but later demoted to a Herring gull subspecies, and L. vegae, named in 1887 and also later demoted to a subspecies of L. argentatus).
* I wrote about this at Tet Zoo ver 1 in 2006 [here] after being surprised at seeing Richard Dawkins’ promoting the ring-species model in The Ancestor’s Tale.
It seems that Smith had one particular piece of research to hand: Kerr et al.’s 2007 paper ‘Comprehensive DNA barcode coverage of North American birds’ (Kerr et al. 2007). Does this paper really conclude that eight morphologically distinct white-headed gulls should be sunk into one? No, it does not. What it does say is that the DNA barcodes of the eight species overlap somewhat, as do those of 17 other sets of North American bird species, and that there are three possible explanations for this. (1) That the species have only diverged very recently and have yet to accumulate sequences differences within cytochrome c oxidase 1, the mitochondrial gene looked at in the study (the barcode study was based on data from a single gene); (2) that the species are doing a lot of hybridising; or (3) that they really are part of a single species. I therefore feel that Smith’s emphasis on the ‘all those gulls are virtually the same’ line to be misleading. Nobody doubts that all these gulls are very similar, but the study that Smith discusses did not come along and present some magic new perspective on this situation. In fact, if anything, Kerr et al. (2007) drew attention to the fact that their data indicated the presence of multiple cryptic species within the avifauna of North America.
Smith also includes a piece on the Kayan Mentarang animal: that peculiar, long-tailed, reddish mammal photographed at a Bornean camera-trap in 2003 (not 2005, as Smith says). By 2006 it was thought by many that the animal was not the new viverrid or mystery pseudo-lemur that some had thought but, in fact, a giant flying squirrel. I wrote about this at Tet Zoo ver 1 (2006) here and here, and Meijaard et al. (2006) published on it in Mammal Review. Given that Smith’s book was published in 2007, and probably mostly written in that year (the acknowledgements are dated ‘2007’), it is surprising that he hadn’t caught up on any of this.
A major gripe I have is that there is no bibliography whatsoever. I’m not entirely stupid: I know full well that publishers often don’t want authors citing references and listing papers and articles at the back of a book. But this book has nothing at all; at the very least it could have included tiny (8-point or something) ‘source notes’ or such on each page (there is plenty enough space on the pages for this). A list of journal titles is given in the acknowledgements, but that’s because Smith is acknowledging help, not citing sources. There is also, sin of sins, no index.
Anyway, enough complaining; this is a lavishly illustrated book that, despite my dissatisfaction, does a great job of bringing the wonder of science to the masses. Smith’s discussions of the discoveries he writes about are short, succinct and only really tell the highlights. That might prove annoying when you want to know more, but the whole point is that that’s not what this book is about: as it says on the back cover, Why the Lion Grew Its Mane is ‘entertaining – a colourful tour through the world of cutting edge science’. If it encourages any of its readers to go deeper – if it ignites the spark that makes them want to know more about any of the subjects it covers, then it’s done a great job and is a good ambassador for science, for knowledge, and for the wonder of discovery.
Smith, L. 2007. Why the Lion Grew Its Mane. Papadakis (London), pp. 287. ISBN 978-1901092837. UK price £20. See www.papadakis.net.
Refs – –
Crochet, P. A., Chen, J. Z., Pons, J. M., Lebreton, J. D., Hebert, P. D. N. & Bonhomme, F. 2003. Genetic differentiation at nuclear and mitochondrial loci among large white-headed gulls: sex biased interspecific gene flow? Evolution 57, 2865-2878.
Gnoske, T. P., Celesia, G. G. & Kerbis Peterhans, J. C. 2006. Dissociation between mane development and sexual maturity in lions (Panthera leo): solution to the Tsavo riddle? Journal of Zoology 270, 551-560.
Kays, R. W. & Patterson, B. D. 2002. Mane variation in African lions and its social correlates. Canadian Journal of Zoology 80, 471-478.
Kerr, K. C. R., Stoeckle, M. Y., Dove, C. J., Weigt, L. A., Francis, C. M. & Hebert, P. D. N. 2007. Comprehensive DNA barcode coverage of North American birds. Molecular Ecology Notes doi: 10.1111/j.1471-8286.2006.01670.x
Meijaard, E., Kitchener, A. C. & Smeenk, C. 2006. ‘New Bornean carnivore’ is most likely a little known flying squirrel. Mammal Review 36, 318-324.
Olsen, K. M. & Larsson, H. 2004. Gulls of North America, Europe, and Asia. Princeton University Press, Princeton.
Patterson, B. D. 2004. The Lions of Tsavo: Exploring the Legacy of Africa’s Notorious Man-Eaters. McGraw-Hill, New York.
– ., Kays, R. W., Kasiki, S. M. & Sebestyen, V. M. 2006. Developmental effects of climate on the lion’s mane (Panthera leo). Journal of Mammalogy 87, 193-200.
Pons, J.-M., Hassanin, A., & Crochet, P.-A. 2005. Phylogenetic relationships within the Laridae (Charadriiformes: Aves) inferred from mitochondrial markers. Molecular Phylogenetics and Evolution 37, 686-699.