Zoology Jottings

Thursday, 26 June 2014

In Search of a Penguin’s Egg. Why?...Continued

Since writing In Search of a Penguin’s Egg. Why? on 8 April, I have read more and more on antarctic exploration in order: first, to understand why Edward Wilson, chief of the scientific staff of Scott’s final (1910-1912) expedition and who died with Scott, was willing to go to such lengths to obtain embryos of the Emperor Penguin; second, to try to understand why the Falkland Islands Dependency Survey (FIDS) was still trying to collect embryos in the late 1950s. I have also found, in the literature, the fate of the embryos collected by Nelson Norman in 1959.

However, the Scott expeditions (Discovery, 1901-04; Terra Nova, 1910-1912) were not the first to collect penguin embryos. Robert Neal Rudmose Brown (1879-1957) and James Hunter Harvey Pirie (1878-1965), members of the Scottish National Antarctic Expedition led by William Speirs Bruce (1867-1924), collected embryos at different stages of development of the Gentoo (Pygoscelis papua) and Adélie (P. adeliae) penguins. These embryos were brought back to Edinburgh where they were examined by David Waterston and Auckland Campbell Geddes of the anatomy department ‘through the kindness of Dr W.S. Bruce’.

The Scottish National Antarctic Expedition^‡ left Troon on 2 November 1902. Scotia, formerly the Norewegian whaler Hekla, had been refitted for the antarctic at the now defunct Ailsa shipyard in Troon, a short distance from where I shall be teeing off from the 1st at Royal Troon at 7.50, as usual on Fridays, tomorrow morning (weather permitting, of course). This successful expedition returned on 21 July 1904 to the Marine Biological Station at Millport, now sadly reduced to a study centre for schools. I shall return to the Scottish National Antarctic Expedition later since its very existence has a bearing on later developments.

Route of the Scotia

Scotia

Waterston and Geddes wrote up their findings for the expedition’s report published on 21 October 1909.

With regard to these developmental facts the question arises:— Is the duck's or the penguin's wing the more direct descendant of the common ancestor; or have they both diverged from the common stock approximately equally, but in opposite directions. Embryology alone cannot answer this question, but the evidence is clear in this, that the fore limb of the penguin in its development goes through a progressive and continuous series of stages along one unbroken line. The mesoblastic portion of the fore limb elongates, but its characters do not alter. It elongates, however, with a relatively greater rapidity towards the end of development, whereas the duck's fore limb, after being relatively longer than the penguin's ever is, regresses rapidly. So that the answer to our question, so far as the embryological evidence is concerned, must be that the wings of both these birds are different from the ancestral wing, and that the differentiation has been in opposite directions and that the common ancestor was a flying bird of a somewhat primitive type depending in large measure for the spread of its wing upon bone and muscle.

Their conclusions could not be more clear; the ancestor of modern birds and penguins was a flying bird.

One of the two laboratories on Scotia

Bruce had placed his penguin specimens with two of the leading anatomists/embryologists in Britain. David Waterston was demonstrator in anatomy at Edinburgh. In 1909, the year of publication of the report, he went to the chair at King’s College, London but in 1914 moved to the Bute chair of anatomy at St Andrews (as a golfer he perhaps could not resist the temptation of the Old Course). He died at the age of 70 in 1942, still occupying the Bute chair.

Coats Land. The expedition named this part of the
continent for the Coats family, the sewing cotton
manufacturers (now the multinational Coats plc),
who funded the expedition.

Auckland Campbell Geddes went on to a remarkable career. At the time of the penguin work he was assistant to the Professor (only one per department in those days), D.J. Cunningham, author of the famous Manual of Practical Anatomy. On graduation in 1908, he was appointed demonstrator. He was late to qualify because he had interrupted his medical studies to serve in the Highland Light Infantry during the Boer War.

His first public achievement from 1908 lived on until recently. His suggestion that the army volunteer force should be named The Territorial Force was adopted by Lord Haldane (JBS’s uncle), then Secretary of State for War. In 1909 he went to Dublin as Professor of Anatomy and then, in 1913, to McGill University in Montreal. He returned on the outbreak of war. He rose from Major in the 17th Northumberland Fusiliers in 1914 to Brigadier-General and Director of Recruiting at the War Office in 1916-17. He was then elected Member of Parliament for Basingstoke and Andover in 1917, becoming Minister of National Service from 1917 to 1919. He was then British Ambassador to Washington from 1920 to 1923. Sadly, he lost the sight of one eye. After his recovery, he served as Chairman of Rio Tinto. in 1942 he was injured by a flying bomb and also lost the sight of his other eye. He became Baron Geddes of Rolvenden in 1942. He died in 1954, aged 74.

The collectors of the penguin eggs also became well established. Rudmose Brown (1879-1957) was botanist on the Scotia Expedition. After working for Bruce after their return, he turned to geography, becoming Lecturer at Sheffield in 1907 and Reader at Manchester in 1920. He returned to Sheffield as Professor of Geography in 1931, retiring in 1945. In both World Wars, he served in Admiralty intelligence. Throughout, he continued his interest in the Arctic and Antarctic. He died in Sheffield in 1957.

Pirie (1878-1965) was the expedition’s medical officer, geologist and bacteriologist. On his return he was a medical practitioner in Edinburgh until 1913 when he joined the Colonial Service as a bacteriologist in Kenya. He was Deputy Director of the South African Institute for Medical Research from 1926 until 1941. In 1940 he gave the name Listeria (after Joseph Lister) to the bacterial genus. In 1948 he was living in Bournemouth on the south coast of England.

So, did Wilson not realise that the findings from the Scotia expedition would render his quest for Emperor penguin embryos unnecessary? Or did he judge the Emperor to be so different, in fact unrelated to the Adelie and Gentoo, that he thought the findings irrelevant? Was he even aware of the results from the Scotia expedition? Was he too busy with his work on the grouse disease inqjuiry and preparing for the Terra Nova expedition to study Waterston and Geddes’s findings between their publication in October 1909 and the departure of the Terra Nova in June 1910? I have been unable to find the answers to any of these questions from reading about Edward Wilson.

However, here’s where the politics of polar exploration kicks in. The Scotia expedition and its leader, Bruce, were regarded as the lowest forms of life by the power broker in British antarctic exploration, Sir Clement Markham, President of the Royal Geographical Society. All my reading indicates that Markham was rightly considered by later commentators a classic Monster. However, Markham’s personality is beside the point. The animus to Bruce was so great that I find it difficult to see Wilson raising any of the (excellent) results of that expedition in discussions over whether it was worthwhile to attempt the journey to Cape Crozier to collect the Emperor embryos with Markham in full control of the expedition and Scott, Wilson’s friend but Markham’s protégé.

From what I have read so far, I conclude that the collection of Emperor embryos was Wilson’s big ‘thing’ and had been his big ‘thing’ since his earlier discoveries on this species in the Discovery expedition of 1901-1904.

Geoge Seaver, in his book on Wilson, states that he gave three lectures to fellow expedition members and that ‘his own notes of them have been preserved but those taken by Scott and others are not without interest…In his second lecture he traced the descent of Penguins from the primitive lizard-bird, explaining their anatomy, and finding corroborative evidence in their primitive fossilized remains’. Those notes could well be worth examining anew to see what Wilson’s understanding was at that time.

Apsley Cherry-Garrard, Wilson’s protégé, who with Wilson and Bowers undertook that indescribable winter journey from Cape Evans to the rookery at Cape Crozier wrote in The Worst Journey in the World:

What is this venture? Why is the embryo of the Emperor penguin so important to Science? And why should three sane and common-sense explorers be sledging away on a winter's night to a Cape which has only been visited before in daylight, and then with very great difficulty?The Emperor is a bird which cannot fly, lives on fish and never steps on land even to breed. It lays its eggs on the bare ice during the winter and carries out the whole process of incubation on the sea-ice, resting the egg upon its feet, pressed closely to the lower abdomen. But it is because the Emperor is probably the most primitive bird in existence that the working out of his embryology is so important. The embryo shows remains of the development of an animal in former ages and former states; it recapitulates its former lives. The embryo of an Emperor may prove the missing link between birds and the reptiles from which birds have sprung*.

After the deaths of Scott, Wilson, Bowers, Oates and Edgar Evans on their return from the Pole, Cherry-Garrard obtained a series of embryos from Adélie Penguins at Cape Royde. He wrote:

It was always Wilson's idea that embryology was the next job of a vertebral zoologist down south. I have already explained that the penguin is an interesting link in the evolutionary chain, and the object of getting this embryo is to find out where the penguins come in. Whether or no they are more primitive than other nonflying birds, such as the apteryx, the ostrich, the rhea and the moa, which last is only just extinct, is an open question. But wingless birds are still hanging on to the promontories of the southern continents, where there is less rivalry than in the highly populated land areas of the north. It may be that penguins are descended from ancestors who lived in the northern hemisphere in a winged condition (even now you may sometimes see them try to fly), and that they have been driven towards the south.

If penguins are primitive, it is rational to infer that the most primitive penguin is farthest south. These are the two Antarcticists, the Emperor and the Adélie. The latter appears to be the more numerous and successful of the two, and for this reason we are inclined to search among the Emperors as being among the most primitive penguins, if not the most primitive of birds now living: hence the Winter Journey. I was glad to get, in addition, this series of Adélie penguins' embryos, feeling somewhat like a giant who had wandered on to the wrong planet, and who was distinctly in the way of its true inhabitants.

So Cherry-Garrard in 1922 seems to be expressing a different reason for collecting embryos—that the most southern could be the most primitive penguins but not the most primitive bird—from Wilson in 1910. But the phrase if not the most primitive of birds now living could be taken to mean that it still might be shown that the Emperor is the most primitive bird. Alternatively, if not actually means even if not. I tend to think it means the latter since otherwise he would be contradicting himself in these paragraphs.

Cherry-Garrard collected embryos from the Adélies during that period after the remaining members of the expedition found the bodies of the polar party, Scott, Wilson and Bowers. Surely Wilson in the many months they had together would have mentioned to Cherry-Gerrard whether Adéle embryos had been examined previously. That leads me to think that Wilson had not seen the report of the Scotia Expedition before embarking on Terra Nova. Original documents and notes on the contents of the libary taken by Scott and his party could well provide more information.

The story of penguin embryos does not end there…

----------------------

Waterston D, Geddes AC (1909) Report upon the anatomy and embryology of the penguins collected by the Scottish National Antarctic Expedition. Transactions of the Royal Society of Edinburgh 47 part 2, number 10, 223-244

Seaver, G (1933) Edward Wilson of the Antarctic. Naturalist and Friend. London: John Murray

*There is a difference in wording between the Pimlico edition 2003 (Vintage 2010) and that available online as a Project Gutenberg eBook; the latter appears to be from the original 1922 edition published by Constable in 1922.

‡Excellent photographs of the expedition are at:

http://gdl.cdlr.strath.ac.uk/scotia/ and http://special.lib.gla.ac.uk/exhibns/month/apr2004.html

Monday, 16 June 2014

Forest Elephants in the Republic of Congo. What Species Were We Observing?

Opportunities to see the animals of the central African rainforests do not come every day. So the privilege of being able to visit groups of lowland gorillas and observe the other mammals, birds, reptiles and amphibians in the Congo Basin is an experience of a lifetime. In the middle of May we were with a group of ten clients of Naturetrek in the camps in the Republic of Congo run by Wilderness Safaris, Ngaga and Lango, 340 miles from Brazzaville, both in or adjacent to the Odzala-Kokoua National Park.

Lango Camp (the word ‘camp’ should be in inverted commas) is situated with views from the raised deck of Lango bai. Watching the bai as animals turn up is a delight, especially in the early morning when large flocks of African Green Pigeons fly overhead and African Grey Parrots appear from the forest to eat mud churned up by the elephants and buffalo. And by elephants I mean Forest Elephants and by buffalo, Forest Buffalo. Later in the day, solitary Bushbuck appeared and, just after our arrival, a Sitatunga.

This video shows what we saw at Lango Camp.

Talking about Forest Elephants with our guides, Justine, Alon and Adam, and the differences between forest and savanna elephants I knew that over the last century there had been arguments to and fro as to whether the Forest Elephant was a different species from the African Elephant. All the more recent books seemed to repeat the view that there was only one species of Elephant in Africa. I was also vaguely aware that the Forest Buffalo was not considered to be a separate species and that, recently, the Bushbuck had been split by somebody into two species.

Because when I actually saw Forest Elephants for the first time in the flesh and could appreciate that morphologically they were very different from the elephants we had seen in other parts of Africa, I resolved to look up their status in more detail when we got back.

Behaviourally too the Forest Elephant is very different. The nocturnal shrieks and cries that kept us awake as elephants gathered further down the bai were very different from the silence or low grumblings of other elephants. My natural tendency as a ‘lumper’ to think of one species of elephant in Africa was being shaken to the core at 2.00 am.

To cut a long story short, I am now convinced by the evidence available that the Forest Elephant is a separate species, that named by Matschie in 1900 as Loxodonta cyclotis. But in reading the papers, I was struck by the strange reluctance of many to accept this conclusion. IUCN still lumps all the elephants in Africa as Loxodonta africana.

Leaving aside the morphological differences and questions of gene flow between Forest and Savanna or Bush Elephants for the moment, the arguments that have arisen in the past 15 years or so have centred on genetic differences in populations of elephants in Africa. Different results were obtained using mitochondrial DNA (mtDNA) compared to nuclear DNA (nDNA).

The use of nuclear DNA to determine the phylogeny of elephants has been championed by Alfred L Roca’s group at the University of Illinois at Urbana-Champaign. Their first work was published in 2001 and showed a clear distinction between Forest and Savanna elephants. However, the single-species-in-Africa view continued as more work using mitochondrial DNA showed a number of geographically based clades. Nevertheless, continuing work by Roca’s group on nuclear DNA demonstrated that Forest and Savanna elephants were different and that mitochondrial DNA does not provide information on which the phylogeny of these species can be determined. In short, mitochondrial DNA provides a historical record of only the maternal line and with the introgression of genes by early hybridisation between separating lines during speciation or by later hybridisation leading to some fertile offspring, the mitochondrial DNA may bear no relation to the nuclear DNA of the species as a whole. As one paper (Rohland, Reich, Mallick, Meyer, Green, Georgiadis, Roca & Hofreiter, 2010) puts it:

…mtDNA represents just a single locus in the genome and need not represent the true species phylogeny since a single gene tree can differ from the consensus species tree of the taxa in question. Generalizing about species relationships based on mtDNA alone is especially problematic for the Elephantidae because their core social groups (‘‘herds’’) are matrilocal, with females rarely, if ever, dispersing across groups. This results in mtDNA genealogies in both African and Asian elephants that exhibit deeper divergence and/or different phylogeographic patterns than the nuclear genome.

Further strengthening of the case for two species in Africa came from work comparing these two elephants with the Asian Elephant and the relatively recently extinct Woolly Mammoth and American Mastodon. Rohland et al. (2010) reported (with my emphasis in bold characters):

We have used a combination of modern DNA sequencing and targeted PCR amplification to obtain a large data set for comparing American mastodon, woolly mammoth, Asian elephant, African savanna elephant, and African forest elephant. We unequivocally establish that the Asian elephant is the sister species to the woolly mammoth. A surprising finding from our study is that the divergence of African savanna and forest elephants—which some have argued to be two populations of the same species—is about as ancient as the divergence of Asian elephants and mammoths. Given their ancient divergence, we conclude that African savanna and forest elephants should be classified as two distinct species.

And then, on the two African species (with references deleted):

Our study also infers a strikingly deep population divergence time between forest and savanna elephant, supporting morphological and genetic studies that have classified forest and savanna elephants as distinct species. The finding of deep nuclear divergence is important in light of findings from mtDNA, which indicate that the F-haplogroup is shared between some forest and savanna elephants, implying a common maternal ancestor within the last half million years. The incongruent patterns between the nuclear genome and mtDNA (‘‘cytonuclear dissociation’’) have been hypothesized to be related to the matrilocal behavior of elephantids, whereby males disperse from core social groups (‘‘herds’’) but females do not. If forest elephant female herds experienced repeated waves of migration from dominant savanna bulls, displacing more and more of the nuclear gene pool in each wave, this could explain why today there are some savanna herds that have mtDNA that is characteristic of forest elephants but little or no trace of forest DNA in the nuclear genome. In the future, it may be possible to distinguish between models of a single ancient population split between forest and savanna elephants, or an even older split with longer drawn out gene flow, by applying methods like Isolation and Migration (IM) models to data sets including more individuals.

The problems inherent in using mitochondrial DNA have been stressed recently by Jerry Coyne in his blog, Why Evolution is True, in relation to the evolution of the Brown Bear and the Polar Bear in which conclusions drawn from mitochondrial DNA have been shown to confuse rather than illuminate. This is a screen grab from his blog:

This entry can be found at:
http://bit.ly/1lJEwmH

IUCN still persists in lumping all the elephants in Africa into one species. However, in a hard-hitting paragraph in the discussion of their paper, Ishida, Oleksyk, Georgiadis, David, Zhao, Stephens, Kolokotronis & Roca (2011) state the case clearly and why it is important for practical conservation:

“Mitochondrial essentialism” and the conservation of Africa's elephantsGiven that mtDNA haplotypes among elephants are an unreliable indicator of overall genetic similarity it is unfortunate that mtDNA alone continues to be used as a guide to elephant genealogical affinities. This “mitochondrial essentialism,” the continuing use of mtDNA to partition populations and species, among elephants where morphological and nuclear markers have established that mtDNA patterns may be inaccurate or misleading, might lead to adverse results for elephant conservation, as the following examples illustrate: If mtDNA data were used as the sole basis for elephant taxonomy and population structure, elephants in the Guinean forest block could be recommended for translocation to the deserts of Mali, on the grounds that their mtDNA similarity implies that they must be genetically similar. Likewise, relying on mtDNA to infer population structure would mean that savanna elephants from Tanzania could be moved west into the Congolian tropical forest, since forest and savanna elephants in these regions share similar F clade mtDNAs. Either of these translocations would be inappropriate, since even while carrying mtDNA from the same haplogroup, individuals in forest and savanna locations are very different in nuclear genotypes, belong to different species, and are thus unlikely to thrive when moved to the wrong habitats. Although the examples are extreme, it may be equally troublesome that mtDNA-based misinterpretations of African elephant taxonomy constitute an unacknowledged potential hindrance to their proper conservation by convincing conservation groups to “continue to treat African elephants as a single species”.

Although studies based solely on mitochondrial DNA appear to be useless in this and many other cases, there is a bonus as Roca and his colleagues have both pointed out and actually worked on: the use of both nuclear and mitochondrial genetic markers can more accurately determine the geographical source of poached ivory.

But now we come full circle. The Forest Elephant was described as a new species by Professor Dr (Georg Friedrich) Paul Matschie (1861-1926) in 1900. Unfortunately, Matschie, who somehow rose to be Director of the Berlin Museum in 1924, was treated as a joke by fellow professionals. An anti-Darwinian mystic, he described a new species or subspecies from pretty well every specimen that fell under his gaze. Mammalian taxonomy seems to have suffered mightily as a result of his activities. His antics and those of his protégé are described, unfortunately briefly, by Colin Groves and the late Peter Grubb in their book, Ungulate Taxonomy (Johns Hopkins University Press, 2011). The ultimate splitter caused a lumping backlash. (Groves and Grubb, incidentally were responsible for the morphological work that resurrected the two-species-in-Africa idea in 2000.) I have the suspicion that Matchie’s involvement in erecting Loxodonta cyclotis may have been one of the reasons why there was such opposition to the possibility of the existence of a separate Forest Elephant in the last century. So, sadly, it appears that Matschie, for once, was right. Maybe right for the wrong reasons but right.

For those wanting more information, these papers and the references therein contain the story as it stands at the moment.

Roca AL, Georgiadis N, Pecon-Slattery J, O’Brien SJ (2001) Genetic Evidence for Two Species of Elephant in Africa. Science 293, 1473-1477

Ishida Y, Oleksyk TK, Georgiadis NJ, David VA, Zhao K, Stephens RM, Koloktronis, S-O, Roca AL (2011) Reconciling Apparent Conflicts between Mitochondrial and Nuclear Phylogenies in African Elephants. PLoS ONE 6(6): e20642. doi:10.1371/journal.pone.0020642

Roca AL, Georgiadis N, O’Brien SJ (2004) Cytonuclear genomic dissociation in African elephant species. Nature Genetics 37 96-104

Ishida Y, Demeke Y, Van Coeverden de Groot PJ, Georgiadis NJ, Leggett KEA, Fox VE, Roca AL. Distinguishing Forest and Savanna African Elephants Using Short Nuclear DNA Sequences. Journal of Heredity 2011 610-616

Rohland N, Reich D, Mallick S, Meyer M, Green RE, Georgiadis NJ, Roca AL, Hofreiter M. (2010) Genomic DNA Sequences from Mastodon and Woolly Mammoth Reveal Deep Speciation of Forest and Savanna Elephants. PLoS Biol 8(12): e1000564. doi:10.1371/journal.pbio.1000564

Saturday, 7 June 2014

Sea Snakes: My Only Sighting

My earlier Post on the survival of sea snakes at sea reminded me that I have only seen sea snakes in the wild once, and that was while gently walking from the restaurant at the Shangri La Tanjung Aru Resort, Kota Kinabalu in Sabah (North Borneo) in 1999. The snakes were crawling among the rocks below the concrete platform that forms the sea front. They were Laticauda colubrina, the banded sea snake. This site is mentioned in the Wikipedia article on this species as a place where they occasionally come ashore. According to that article, the males come ashore in the early evening and the females later.

Laticauda colubrina
Bernard DUPONT from FRANCE
Used on Wikipedia

Modified 9 November 2019

Monday, 12 May 2014

Sea Snakes: Raining on the Parade

An interesting story has hit the newspapers in the last month or so. It is the culmination of research over several years on how sea snakes survive at sea. When Jim Linzell and I wrote our monograph on salt glands in 1975 (Salt Glands in Birds and Reptiles) the first part of the story had been completed. Between 1966 and 1971 Bill Dunson and his colleagues established that there is a salt gland in sea snakes and that the gland responsible is the posterior sublingual gland which empties into the tongue sheath. So it was clear then, as it remains clear now, that extra-renal salt excretion is, as in marine birds, used for survival at sea. However, those findings did not mean, as some have taken them to mean, that even the most pelagic sea-snakes can survive entirely without freshwater or that the latter is not either sought out for drinking or preferred to sea water when both are available. There always lurked in the back of the mind the suspicion that the glands were simply not big enough in sea-snakes to cope with a fully marine life, i.e. the ability to drink seawater and then eliminate all the excess salt through the salt glands to obtain osmotically free water.

Yellow-bellied Sea Snake
By Aloaiza
Photograph used by Wikipedia

The species thought most likely to be able to survive without fresh or brackish water was the more pelagic and widely-distributed Pelamis platurus*, the Yellow-bellied Sea Snake. However, the qualms over the truly marine nature, in physiological terms, of this species were never dispelled especially when Dunson and Robinson showed in 1976 that the skin of this species was permeable to water but not to sodium. The outward osmotic flow of water caused a loss in body-weight of 0.4% per day when fasting animals were kept in seawater. So while, the salt gland could account for any salt intake, the snakes were not in water balance; they were slowly dehydrating. Did they somehow return to where they could obtain fresh or estuarine water periodically, was the question. Or was water intake from their fish prey sufficient to balance that loss through the skin?

The question of whether the water losses through the skin could be made up by intake from prey (minus any needs for nitrogenous excretion) has been addressed recently as part of a study of three not nearly so pelagic species of the genus Laticauda that occur around Taiwan. In brief, these snakes could be found in a dehydrated condition in the wild, they would not drink sea or strongly brackish water when dehydrated; they would drink freshwater or weakly brackish water when dehydrated but not hydrated. Calculations suggested that even when feeding, these snakes would gradually be losing water; intake of osmotically free and metabolic water from their prey would be insufficient. Therefore, these snakes seemed to become dehydrated at sea and tolerate that dehydration for weeks and months. The scenario would appear to be that as water is lost osmotically through the skin, and the salt in extracellular fluid retained, they would be able to maintain salt balance by using their salt glands to remove the then excess salt. In other words, volume regulation drifts while ionic balance is maintained—the opposite to the old dogma for vertebrates.

The latest report shows that Pelamis platurus, the most pelagic of all the sea-snakes, becomes dehydrated while in seawater and spends a significant part of its life in a dehydrated state. The snakes do not drink seawater. They must, therefore, obtain freshwater from somewhere. The authors found a relation with rainfall:

Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall…individuals may live in a dehydrated state for possibly six to seven months at a time (Lillywhite et al 2014).

The answer to the source of fresh or weakly brackish water should have been obvious earlier. It is the layer of freshwater that lies for a while on the surface of the sea after heavy rain, freshwater being less dense than seawater. Therefore, after rain, sea snakes can drink freshwater as well as breathe when they come to the surface. As far as I can recall, nobody had thought of this transient source of freshwater as a source of drinking water for marine reptiles or birds in any of the early work on salt glands. This explanation can account for the relation between the distribution of pelagic sea snakes and the rainfall pattern, and could account for the local extinction of populations as rainfall patterns change either cyclically or permanently.

While it looks likely that we shall soon have a pretty complete picture of how sea snakes live at sea from the point of view of salt and water balance, many more questions are raised as to what happens during the periods of dehydration. The condition of dehydrated sea snakes appears from the photographs to be awful. Are they still able to feed? Do the digestive organs remain functional? Is blood volume maintained? What are the electrolyte concentrations in plasma during dehydration and rehydration?

So, if sea snakes rely on rain for fresh water, the question arises of whether turtles, in the British sense, i.e. marine chelonians, also drink and need freshwater. There is a difference between drinking fresh water and needing fresh water because almost all birds with a salt gland will drink freshwater if it is available. This is not surprising. Pumping salt against a large concentration gradient needs a great deal of energy and freshwater would relieve that energy expenditure.

The thought crossed my mind a few years ago that birds we typically regard as marine may have access to temporary supplies of fresh water from the surface of the sea after a tropical shower. Twice in the South Pacific I have been in the front of a Zodiac moving slowly from the shore to ship after a heavy downpour. I could see the interface between the sea and freshwater caused by the difference in refractive index (called, I see, the halocline). So I tasted the top of the surface layer to find not a trace of saltiness. That really made me wonder whether some of the petrels that nest on islands like Ducie and Henderson that lack freshwater, for example, could be using the freshwater forming a layer after rain and if they would seek out a storm in order to do so. If that proves to be the case remember that you read it here first!

But if marine birds could have access to transient supplies of fresh water from rain, what about those in the Arctic and Antarctic where fresh water ice melts in the sea during the summer. Were the Chinstrap, Gentoo and Adélie penguins I saw breeding on the Antarctic peninsula getting freshwater from melting glaciers and sea-ice?

Plenty more research to do then, physiological, ecological and at the interface between the two. Knut Schmidt-Nielsen would have been pleased.

Key References

Lillywhite, H.B., Sheehy, C.M., Brischoux, F., Grech, A. 2014. Pelagic sea snakes dehydrate at sea. Proceedings of the Royal Society B 281 20140119.

Lillywhite, H.B., Babonis, L.S., Sheehy, C.M., Tu, M.-C. 2008. Sea snakes (Laticauda spp.) require fresh drinking water: implication for the distribution and persistence of populations. Physiological and Biochemical Zoology 81, 785-796.

Dunson, W.A., Robinson, G.D. 1976. Sea snake skin: Permeable to water but not to sodium. Journal of Comparative Physiology 108, 303-311.

*Somebody noticed that the Pelamis platurus was incorrect in terms of the rules and latin grammar; platur should have had the feminine ending a and not the masculine ending us. So they changed the name to P platura and some authorities have foolishly followed this change. By all means get it right in the beginning but to change a name afterwards by such nitpicking can only lead to confusion and pull taxonomists and taxonomy even lower in the scientific pecking order.

Monday, 21 April 2014

The Case of the Green Turtle. An Uncensored History of a Conservation Icon by Alison Rieser

I was intrigued by the title of his book. What had been ‘censored’ that could now be revealed was my first question. Even after wading through 338 pages of pretty turgid prose I still do not know. That was my first disappointment.

I also knew well or had met a number of the protagonists in the farming vs total protection debate of the 1970s that forms a substantial part of this book (Amo, Parkes, Brongersma and Bob Bustard) and was intrigued to see what had been written about them.

The early chapters are the most informative because they indicate the size of the problem brought about by commercial turtling, especially in the USA, the Caribbean and Central America and the urgency of national and international conservation measures to decrease the killing of adults and the removal of eggs for human consumption from nesting sites. However, the book soon drops into a dry as dust description of the conferences and legal processes (with emphasis on the USA) by which the Green Turtle came to be protected, nationally and internationally. The wars, between those who really believed that turtle farming would be the eventual answer to meeting the demand from consumers of turtle products (soup, meat and leather) while reducing the pressure on wild populations and those who also really believed that total protection by prohibiting imports was the only way to preserve the species, form a significant part of the book. Unfortunately, the accounts of meetings and discussions between these groups and individuals, to my mind, are written so blandly that they fail to capture the ding-dong battles that were going on. With its concentration on blow-by-blow accounts of legal procedures in the USA (perhaps therein lies its intended readership) the cynical may be forgiven for getting the impression that any potential for wealth creation from the populations of turtles was transferred from turtlers, would-be farmers and local consumers to Washington lawyers.

The book ends suddenly around 1980. Essentially the farming protagonists were defeated by the US import ban. A two-page epilogue, entitled Supply and Demand brings matters up to date in relation to what happened to the Cayman Island farm, to those in the Torres Strait and to some of the IUCN formal procedures. And that is where this book really falls down. The question is simple: have the international measures that were argued over and enacted been effective in conserving green turtle populations? Evidence and opinion would have been welcome. However, I see that IUCN has not updated its assessment beyond 2004 and so the author would have been on her own in trying to find out. This is the 2004 IUCN view:

As a result of these designations and agreements, many of the intentional impacts directed at sea turtles have been lessened: harvest of eggs and adults has been slowed at several nesting areas through nesting beach conservation efforts and an increasing number of community-based initiatives are in place to slow the take of turtles in foraging areas. In regard to incidental take, the implementation of Turtle Excluder Devices has proved to be beneficial in some areas, primarily in the United States and South and Central America (National Research Council 1990). However, despite these advances, human impacts continue throughout the world. The lack of effective monitoring in pelagic and near-shore fisheries operations still allows substantial direct and indirect mortality, and the uncontrolled development of coastal and marine habitats threatens to destroy the supporting ecosystems of long-lived green turtles.

In some places, Green Turtles appear plentiful, the Galapagos, for example, where strict protection measures for everything are in force. The last I saw was off the southern tip of Sri Lanka in November diving as the boat approached. However, turtles are clearly and openly being exploited, often illegally, in some key areas. We saw turtle eggs for sale in the Sandakan market in Sabah, which I still call North Borneo. I see from the online editions of the local papers that the eggs are thought to be brought in by boat from the nearby Philippines and that efforts are being made to stamp the trade out.

Many of the protagonists involved in the 1970s were alive when this book was written. It would have been interesting and, I would argue, only fair to have asked them for their views as to whether they would take the same view now as they did then and whether they think the measures taken then have actually worked. A what-happened-next to the scientific programme of the Cayman farm would also have been interesting, resulting as it did in a complete breakdown in relations between Amo and Parkes, as recounted in Roger Short’s perceptive biographical memoir of Amo.

It is only fair to also ask me if I can remember what I thought then, with Amo around most days for coffee and tea or a chat in the lab (although he was strangely reticent on what was happening in the Caymans). I also heard Parkes give a couple of talks. I think I thought, along with a number of others, that the Cayman Islands team had done a good job in breeding the Green Turtle in captivity at a time when only a few species of reptile had been bred and in studying the reproductive physiology. That convinced many of us that captive breeding could succeed if needed as an emergency measure, even if the facilities needed would be both extensive and expensive.

On the key economic question of whether the farming of turtles would decrease demand from the wild or simply increase it if turtle products were to become more popular to consumers in Europe and North America, I think I was unconvinced then as I am now. In this respect, it would be interesting to know whether the farming of freshwater chelonians (‘turtles’ to Americans and ‘terrapins’ to Brits) in China, which is now said to be on a vast scale, is reducing the pressure on wild populations.

Killing the supply to the USA and Europe for turtle soup and turtle meat by prohibiting imports may well have had an effect in reducing global demand and the consumer desirability of all turtle products. But in the 1970s turtles were not the charismatic creatures that turned them into the conservation icons they are now. Television wildlife programmes must have helped but can you imagine trying to serve turtle soup or meat to those fed a television and toy marketing diet of Mutant Ninja Turtles in the 1980s.

Perhaps, then, the most telling statement is hidden in the endnotes of Rieser’s book. Archie Carr 1909-1987), the doyen of turtle biology and conservation, had originally proposed commercial farming as a conservation measure but had then turned against it:

Peter Pritchard…reported that Carr had in fact been less than friendly to former associates who condoned the killing of sea turtles…Pritchard acknowledged that Carr “was quite frank about his emotional attachment to his creatures when questioned by a newspaper reporter a month before he died in 1987: ‘I just like the look on their faces’ he replied. Pritchard believes that as Carr grew older, his emotional attachment caused him to give up eating turtle meat and opposed turtle farming. Carr simple “could not abide their killing for any reason, and broke off relationships with those who felt otherwise.”

Rieser, A. 2012. The Case of the Green Turtle. An Uncensored History of a Conservation Icon. Baltimore: Johns Hopkins University Press. ISBN 978-1-4214-0579-7

Polge, C. 2006. Sir Alan Sterling Parkes. Biographical Memoirs of Fellows of the Royal Society. 52, 263-283

Short, R.V. 1985. Emmanuel Ciprian Amoroso. Biographical Memoirs of Fellows of the Royal Society. 31, 3-30

Saturday, 12 April 2014

Government Committees: A Lancelot Hogben Quote

Lancelot Hogben (1895-1975) clearly loathed Sir Alexander Carr-Saunders (1886-1966), eugenicist and Director of the London School of Economics from 1937 to 1957. In his unpublished autobiography (reshaped by Adrian and Anne Hogben as Lancelot Hogben Scientific Humanist, Merlin Press, 1998) he wrote: It used to puzzle me how any one so facelessly devoid of charm and with so mediocre intellectual equipment attained such eminence. It does so no longer.

He then continued:

The first rung on the ladder is a place on a minor government committee. If one remains somnolently acquiescent to the pressure group in command news spreads among civil servants that one is a sound chap due yo fill a vacancy on [an]other ministerial committee, somnolently—and so on and so on.

Some things never change.

Tuesday, 8 April 2014

In Search of a Penguin’s Egg. Why?

Nelson Norman’s 2009 book, In Search of a Penguin’s Egg, worked its way to the top of my to-be-read pile and I found it a fascinating account of how he came to be sent, as a newly-qualified medical graduate doing his National Service, to Antarctica as a medical officer and voluntary general factotum to the Falkland Islands Dependencies Survey (FIDS) (now the British Antarctic Survey) at Halley Bay for the antarctic winter of 1959.

As part of his research activity he was asked by Sir Raymond Priestley, an Antarctic explorer in his younger days and former vice-chancellor of the University of Birmingham who was still active with FIDS, to obtain a series of Emperor Penguin embryos at 12-hour intervals over the first ten days of incubation:

…he told me that 4 or 5 kilometres from Halley Bay, there was a rookery of emperor penguins…He told me that these birds were close to being the most primitive species of bird and possibly the embryological link in the evolutionary chain between reptiles and birds. They were thus if great scientific importance. There was an anatomist at Charing Cross Hospital who was desperate to get a precisely timed series of emperor penguin embryos at twelve-hour intervals for ten days. He stressed the importance of this and asked me to secure them…Nor did he tell me that a previous attempt had been made during Scott’s last expedition and that only one man had survived—Apsley Cherry-Garrard.

Before his departure, Norman had a half-hour meeting with Dr Glenister of Charing Cross Hospital who repeated his requirement for the timed series of preserved embryos.

By ingenuity, dedication and fortitude—but not without danger during the Antarctic winter—Norman succeeded in bringing back the series of embryos. However, the reception of his embryos in London was less than enthusiastic:

…The taxi crossing London did not crash—as had been my recurring nightmare in Antarctica—neither was the enthusiastic Dr Glenister standing on the front steps to meet me. I was informed politely but rather coldly by a secretary that he was now the Professor of Anatomy and a a very busy man. I was, therefore, invited to leave the embryos and my report with a technician and basically just to go away. I did this rather reluctantly and unhappily, and I never heard anything more from Professor Glenister though I did think that he could at least have written a short note of thanks considering what we had gone through to produce the embryos. I enquired several times over the years and was persistently told by FIDS that the embryos were being worked on…Nearly fifteen years later when I was in a position to consider the matter further and was a research director myself I went to the British Antarctic Survey (as FIDS was known by that time), expressed my concern, and asked for my embryos back saying that I would find an interested embryologist and we would work them up between us. This was agreed but when it asked for the embryos, the Survey was told that a technician had accidentally disposed of them!

What an appalling way to treat a young scientist, was my thought as I read Nelson’s account. But the reason for writing this post is to remark that this sort of treatment of young scientists and technicians was by no means uncommon. I have known individuals who have worked hard to complete a task, only for the specimens or results to be ignored for weeks, months, years and, sometimes, for ever.

So why was Nelson launched on this ultimately worthless mission? The story is well known of how Edward Wilson, chief of the scientific staff of Scott’s final (1910-1912) expedition and who died with Scott and his party, had become convinced that by studying the embryonic development of the Emperor Penguin he could follow the evolutionary transition from reptiles to birds. In 1907, in his report on the 1901-1904 expedition in which the breeding cycle of this species was discovered, he wrote: The possibility that we have in the Emperor Penguin the nearest approach to a primitive form not only of penguins but of a bird, makes the future working out of its embryology a matter of the greatest importance. It was a great disappointment to us that although we discovered their breeding ground. and although we were able to bring home a number of deserted eggs and chicks, we were not able to procure early embryos by which alone the points of particular interest can be worked out. Obtaining embryos was Wilson’s aim when he set off in 1910.

The appalling conditions endured by Wilson, Henry Bowers and Apsley Cherry-Garrard in their search for the eggs are described by Apsley-Garrard in his book, The Worst Journey in the World. Three eggs survived the six-week, 65-mile return journey from Cape Crozier. The three men also survived this part of the expedition; Wilson and Bowers then died with Scott’s party. It would appear that Cherry-Garrard’s life was wrecked by the trauma of the whole expedition and its outcome.

The enthusiasm of the Natural History Museum for the receipt of Cherry-Garrard’s eggs in 1913 was a forerunner of the enthusiasm of Glenister for the arrival Nelson’s embryos. The account in The Worst Journey in the World of his encounter with the Museum’s officialdom is an example of British jobsworths at their finest. However, the 1911 embryos were worked on, first by Dr Richard Assheton FRS, lecturer in embryology at Cambridge who died in 1915, then by Professor Cossar Ewart FRS, professor of natural history in Edinburgh, who produced a report that can only be described as kindly and, finally, 20 years after their collection, by Charles Wynford Parsons FRSE (1901-1950) of the University of Glasgow. Parsons did not pull any punches: [the eggs] have not contributed much to the understanding of the embryology of penguins.

View of the Emperor Penguin Rookery at Cape Crozier by Edward Adrian Wilson
From his report of the 1901-04 Expedition

Before moving to consider why, during the 1950s, the collection of Emperor Penguin eggs was considered to be of such importance to FIDS, what drove the enthusiasm of Wilson in the first place?

Two influences are said to have driven him. The first, which seems bizarre to the point of craziness when looked at now and perhaps even then, was the suggestion in a long paper by Mikhail Aleksandrovich Menzbier (1855-1935), professor of comparative anatomy in Moscow, that penguins had evolved separately from reptiles on a parallel evolutionary line to other birds. However, the argument that Wilson got his impetus from Menzbier does not quite stack up with his statement, The possibility that we have in the Emperor Penguin the nearest approach to a primitive form not only of penguins but of a bird. Wilson seemed to have the impression that the Emperor Penguin could be the most primitive of all birds which is not what Menzbier was arguing.

The second influence was, of course, recapitulation, the theory of Ernst Haeckel: ontogeny recapitulates phylogeny. The flaws in making this idea a law of nature are so well known that I will not repeat them. However, if true, the development of the Emperor Penguin should, if it were the most primitive bird, show it passing through a reptilian stage relatively late in development. That is what Wilson was hoping the results would decide.

Encouragement along the lines of a separate descent for penguins or for the Emperor Penguin being the primitive bird did not come from the Natural History Museum. W.P Pycraft in the same volume as Wilson’s report of the 1901-1904 expedition wrote:

All that can be gleaned from fossils, then, is that penguins have probably descended from birds which possessed full powers of flight, and this probability becomes converted into a certainty when the embryological evidence comes to be examined. But the question of the precise affinities of this group must still be regarded as an unsolved problem, the intense specialisation which these birds have undergone obliterating much of the necessary evidence.

However, Pycraft was clearly thinking along Haeckelian lines when he supported the collection of more embryos:

Some day another Antarctic Expedition will be sent out, when it is to be hoped that, so far as the penguins are concerned, special efforts will be made to secure the earlier nestling stages of the King, and the latter stages of the Emperor Penguin full-grown nestlings of the latter being especially needed; while of both species the early and middle embryonic stages are wanted. Ripe embryos will add but little of real value to our knowledge, since they differ but little of course from the newly-hatched nestling, and furthermore, several examples are among the spoils of the expedition herein concerned. A few adults of both species would certainly be useful if preserved entire, in spirit, or in ice.

Although ideas, often wrong, on the evolutionary history of penguins rumbled on, the notion that the Emperor Penguin was vital for the study of the origin of birds was well and truly dead by the 1950s. Also by then recapitulation had also been effectively demolished as a doctrine. So why did Sir Raymond Priestley push the importance of collecting a series of embryos to Nelson Norman? Was FIDS in some sort of time warp with its own unchanging research agenda, locked into continuing the unfinished research of dead antarctic heroes? The cynical might be tempted to suggest that some at FIDS were looking for reasons to use the Halley Bay base and its nearby penguin colony for biological research on the use it or lose it principle of government funding. However, since most of the research there was concerned with the physical environment and FIDS was taking over Halley Bay from the Royal Society which had established it for the International Geophysical Year in 1957-58, there may have been no need for a research excuse.

The request to Nelson seemed even more strange to me when I read (not in Norman’s book) that a series of Emperor Penguin embryos (16 from the primitive streak to hatching) had been collected by Bernard Stonehouse in 1949 and described by Glenister in a letter to Nature. Without providing quantitative data, Glenister stated that early penguin embryos (others had described Gentoo and Chinstrap penguin embryos) resemble early reptilian embryos more closely than do early chick embryos. The thought also occurred to me that since the Emperor and King penguins are closely related and, then and now, included in the genus Aptenodytes, why the insistence on Emperor embryos when King Penguins were readily accessible and available in abundance on South Georgia where whaling stations were maintained until the 1960s?

Finally, there is Professor Glenister who seemed less than keen to receive Norman’s embryos. Tony William Alphonse Glenister (1923-1998) was an embryologist at Charing Cross Hospital Medical School. He became Professor of Embryology, then of Anatomy. He was Dean of the Medical School from 1976 to 1984 and then Dean of the combined Charing Cross and Westminster school until 1989. A building is named after him at Imperial College, the final destination of these medical schools in the organisational reshuffles of the London colleges. He was President of the Anatomical Society in 1979-81; he wrote Anatomy and Physiology for Nurses.; he has 18 papers listed in PubMed, mainly on mammalian embryology. Recently, he has been identified as one of the referees who opposed the awarding of a grant to support the work of Edwards and Steptoe on human fertilization in vitro (IVF). In that he was by no means alone.

I do not know how Glenister became involved with the penguin embryos. One explanation is that he was drawn in by FIDS to work on the embryos brought back by Stonehouse. Glenister wrote a report for FIDS entitled, The Emperor penguin, Aptenodytes forsteri Gray: II Embryology. I have not seen this report but I think it is a fuller version of the letter to Nature. His work on the embryos was descriptive and I can only assume that in sending Norman for more he felt that there were gaps to be filled. Whether he then lost interest in the topic or somebody had a quiet word with him that the work was of insufficient scientific importance, whether he became bogged down in university administration or whether his role in the Territorial Army increased, I do not know. Whatever the reason there is no doubt that Norman, quite rightly, felt highly aggrieved by his reception on delivering the embryos, by the lack of contact with Glenister and, later, by their destruction.

Sadly, Nelson Norman’s and Cherry-Garrards’s experiences when they returned were not, and may still not be, uncommon. As to the wider question, of why FIDS persisted in pursuing an outdated notion (hypothesis would be too strong a word), a historian delving into the archives may be able to judge. However, such behaviour would not be unusual for a British government department or agency. Research agendas unchallenged by effective external review were alive and well into the 2000s, to my certain knowledge; some still may be.

The appraisal of Wilson’s pursuit of Emperor Penguin embryos must not detract from his and the other explorers’ achievements in the Heroic Age of Antarctic Exploration. An incredible amount of work was done in all the relevant fields of science; important discoveries emerged from each expedition. The observations and collections they made would have been arduous in a temperate environment; in an antarctic winter with temperatures as low as -61°C survival alone was a triumph.

Antarctica stands head and shoulders above anywhere else in the world I have visited. The scenery, the air, the ice, the mammals and the birds have to be seen and heard to be believed. I can see why the explorers were drawn back.

Our view back to the ship from Jougla Point, Wiencke Island, Port Lockroy in 2005. The furthest south we reached in the Lemaire Channel was still 1722 statute miles from the South Pole.

The ship is the MV Lyubov Orlova which hit the headlines recently (Ghost ship carrying cannibal rats 'may have sunk’, for example) is either drifting in the Atlantic or has sunk.