Saturday, October 14, 2006

Oh deer oh deer oh deer

Welcome to Tetrapod Zoology’s one-hundredth blog post! And I’ve decided to crack open the champagne and celebrate by… writing a post all about temnospondyls rhinogradentians what happened to me on Friday the 13th. Well, originally I was going to do some kind of big analysis of subject distribution across the 100 posts, but having thought about it I can’t be bothered. Seriously, I’ll save that sort of thing for Tetrapod Zoology’s 1st birthday. For some time now Jonathan McGowan and I have been planning to go to the New Forest to watch the rutting deer, and right now is rutting season for Red deer Cervus elaphus, Fallow deer Dama dama, and Sika deer C. nippon. Jon is an outstanding, experienced naturalist (and excellent photographer, and professional taxidermist) and he might be best known for his association with the recently discovered green lizards of Boscombe Cliffs, Bournemouth (see Hunting green lizards in Dorset: new aliens or old natives?). And so it was that we headed off into the wild, eagerly awaiting the many close-hand encounters we would have with big wild deer.

Jon’s collection of deer taxiderm specimens and antlers is amazing, as you can see from the photo above (which depicts only a small fraction of what he has). One of the centrepieces is the big animal you can see here, surrounded by roe deer. It’s an immense reindeer which blew me away in terms of its size and antler form: it appears to be an Osborn’s caribou Rangifer tarandus osborni Allen, 1902, a subspecies I’ve never seen before. Endemic to British Columbia and the Yukon, Osborn’s caribou is a reddish brown animal with a whitish lateral stripe and neck, and long and thick-beamed antlers that have semi-palmate brow and bez tines. And it’s a giant, as you see by comparing it with the adjacent roe. Geist (1999) puts this giantism down to growth in a highly favourable environment combined with a non-migratory habit. That’s right, not all reindeer migrate.

Reindeer are what Geist terms grotesque giants: species that exploit high-quality foods in cold climates, and are able to evolve luxury organs. The latter include large fat deposits, big and ornate antlers, tusks or horns, big brains, and manes or beards of long decorative hair. Big cold-adapted Pleistocene mammoths and rhinos are regarded by Geist as grotesque giants, as are big bears and, most interestingly, neanderthals and modern humans. Strongly adapted for life in open country, reindeer are the most cursorial of living deer. They have the proportionally biggest antlers of any living deer, the most complex pattern of pigmentation and array of ornamentation, among the showiest courtship display, and are among the most adaptable and behaviourally flexible of all deer. That last factor probably explains why reindeer are the only deer that have been properly domesticated.

Anyway, once in the field we headed to a location well known as a regular red deer rut site. But, unfortunately, only a few deer were to be seen, and they were hardly active, spending most of their time lazing in the vegetation. It was a very warm and sunny day, so I can’t blame them. Red deer in Britain have an interesting history. While the species was historically native to Britain, it is doubted if this is true for any of the English populations (even that of Exmoor, often said to be descended from old native stock): Lowe & Gardiner (1974) found that the only truly native red deer are those of the Lake District and Scottish Highlands, with the others being derived from continental introductions. Red deer numbers waxed and waned between the 13th century and the present (Yalden 1999).

We also succeeded in hearing and seeing sika deer, though again not at the close range I was hoping for. Sika are sometimes described as combining an unconventional combination of characteristics: similar in size to fallow, they have a white rump recalling that of a roe, while their antlers are like those of a miniature red. As they flee, their pale rumps are prominent, and while we got to see quite a few fleeing rumps, we also got to within close range of a lone stag. He stopped and watched us for some time, and with large antlers that had ten points we thought that he was a magnificent individual. Prior (1963) stated that New Forest sika stags are unusual ‘for producing occasional heads of ten points instead of the usual eight’ (p. 72), so it’s good to confirm that ten-pointers are still around. Sadly, we weren’t close enough for me to get any photos. The adjacent photo is – honest – a scrape produced by a sika.

Sika are not native, having been introduced from China and Japan (read on) on multiple separate occasions. They haven’t spread that far, though there are amusing cases where populations introduced to islands (such as Brownsea Island in Poole Harbour) have swum to the mainland. Sika are ecotone deer that have been around since the Pliocene, and the larger cold-adapted forms of the species appear especially close to the ancestry of the apparently more advanced red deer. However, it has also been argued that things go the other way round, and that sika might descend from a red deer-like form.

In the New Forest, it is well known that sika occur south-east of the Bournemouth to London railway line, and that any seen north of it are shot. This is due to fears that they will interbreed with the ‘native’ red deer, as it is well documented that – despite their anatomical and ecological differences – the two species readily hybridise, with the hybrids being fully interfertile (which, incidentally, is relevant to the whole ‘domestic dogs represent a distinct species’ argument). Hybrids between red deer and sika have been known since 1940 when they were reported in the Lake District, and by the 1970s it became clear that the Irish deer of the Wicklow Mountains were pretty much all hybrids. Extensive hybridisation has occurred between the two elsewhere in the world, such as in New Zealand (Tate et al. 1997). Today, Scottish red deer – even those that look like good, honest reds – have been significantly contaminated by sika DNA.

As usual however, nature is inconsistent, and I am reliably informed that the latest data on New Forest deer shows that – even when sika get north of that railway line – they _do not_ hybridise with the reds. The consequence of this discovery is that the shooting of New Forest sika has stopped. Quite why sika and reds hybridise in Scotland and Ireland but not in southern England is beyond me, and I don’t know if anyone has proposed a reason. But here’s one. Britain’s introduced sika belong to two different subspecies: C. n. nippon of Japan and C. n. hortulorum of China. Maybe it’s only one of these subspecies that can routinely hybridise with C. elephus, and if this is so, then maybe that’s the subspecies that is doing the hybridisation in Scotland and Ireland. I don’t know, and I’d be interested if anyone does (Long et al. (1998) implied that at least some English sika are C. n. hortulorum whereas most British sika are C. n. nippon, but didn’t go into the subject further than that).

Incidentally, on New Zealand red deer have been extensively hybridised (via artificial insemination) with the highly distinctive Père David’s deer Elaphurus davidianus, and again the hybrids are fertile (Tate et al. 1997). This is odd given that Père David’s deer are significantly different genetically from red deer, differ from them in seasonality, behaviour, morphology and other details. There have also been attempts to cross Sambar C. unicolor with red deer on New Zealand (again via artificial insemination), though in this case only one calf survived of 400 inseminations (Muir et al. 1997).

You might wonder why New Zealanders are so interested in producing these unnatural hybrids. The answer is that the resulting animals are thought to be superior from the point of view of the deer farming trade, theoretically having a more flexible breeding season and shorter gestation period than pure red deer. Similar experiments involving Père David’s deer have been carried out in Scotland, with one argument for the introduction of Père David’s deer genes into red deer being that Père David’s deer is ‘in the words of one enthusiast “as tough as old boots”, and when it is not being eaten by Chinese peasants it will thrive almost anywhere’ (Tudge 1987). Tudge’s article – ‘Custom-built deer take to hills’ – implied that Père David’s x red hybrids would prove a big thing in the years to follow. Well, here we are in 2006 and I haven’t heard much about them lately. Hmm.

We have yet other deer in Britain, and again they are introductions, including Chinese water deer Hydropotes inermis and muntjacs. Muntjacs, aah yes, muntjacs….

For the latest news on Tetrapod Zoology do go here.

Refs - -

Geist, V. 1999. Deer of the World. Swan Hill Press (Shrewsbury).

Long, A. M., Moore, N. P. & Hayden, T. J. 1998. Vocalizations in red deer (Cervus elephus), sika deer (Cervus nippon), and red x sika hybrids. Journal of Zoology 244, 123-134.

Lowe, V. P. W. & Gardiner, A. S. 1974. A re-examination of the subspecies of Red deer (Cervus elephus) with particular reference to the stocks in Britain. Journal of Zoology 174, 185-201.

Muir, P. D., Semiadi, G., Asher, G. W., Broad, T. E., Tate, M. L. & Barry, T. N. 1997. Sambar deer (Cervus unicolor) x Red deer (C. elaphus) interspecies hybrids. The Journal of Heredity 88, 366-372.

Prior, R. 1965. Living With Deer. Andre Deutsch (London).

Tate, M. L., Goosen, G. J., Patene, H., Pearse, A. J., McEwan, K. M. & Fennessy, P. F. 1997. Genetic analysis of Père Davids’ x Red deer interspecies hybrids. The Journal of Heredity 88, 361-365.

Tudge, C. 1987. Custom-built deer take to the hills. New Scientist 114 (1555), 28.

Yalden, D. W. 1999. The History of British Mammals. T & A D Poyser (London).

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Blogger tony said...

Darren, you have a typo in the first parapgraph about the red-sika hybrids that makes you say the opposite of what you mean.

You mean "fertile" not "infertile," no?

4:02 AM  
Anonymous Anonymous said...

Hydropotes inermis! The "unarmed" deer with the sabre teeth! In England! :-o

1:59 PM  
Anonymous Anonymous said...

So the biggest of all reindeer subspecies is non-migratory, and so is the smallest, the platyrhynchus subspecies of Spitzbergen.

This is a small (about a meter over the shoulder), stocky and very short-legged form. In contrast to all other reindeer it is also non-gregarious. In short it is a beautiful example of the changes that routinely take place in an island population which is subject to minimal predation.

7:35 PM  
Blogger Darren Naish said...

Thanks to all for their comments. Tony: I cannot find the word 'infertile' anywhere in the text, but I CAN find the word 'interfertile'. As you can probably guess, 'interfertile' does not = infertile!

On dwarf reindeer, there was of course an even smaller non-migratory form than R. t. platyrhynchus, this being Dawson's caribou R. t. dawsoni (regarded by some as a distinct species) of the Queen Charlotte Islands. It reached c. 84 cm in shoulder height and was markedly short-legged. Sadly, it apparently became extinct in the 1920s. Thanks as always for your comments Tommy.

8:27 PM  

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