American terrapins (or turtles): problems as pets and pests

Red-eared Slider - photograph by Greg Hume (used on Wikipedia)

Those of us who came into the biological sciences through a particular interest in reptiles and amphibians (and there are a good number of us) were sufficiently naive to believe that the few young American terrapins (turtles in US-speak) that occasionally appeared in provincial British pet or aquarist shops in the 1950s and early 1960s represented a relatively small number taken from the vastness of the U.S.A. wilds and that they were easy to keep. We were soon disabused of the latter. The unfortunate terrapins soon developed soft shells and swollen eyelids and only lasted a few months.

The problem was exacerbated was the pet trade itself. There appeared on the British market in 1959 the ‘turtle bowl’ designed it was said to house small terrapins. It came complete with a plastic palm tree and some food in the form of ant pupae. Swift passage to death was assured.

Some people were trying to get the word out that in terms of housing young terrapins had to be kept more like tropical fish. For example, Mrs Monica Green (1925-2014) who was Secretary of the British Herpetological Society for 57 years took the reviser and publisher of a second edition of a booklet published in the 1930s to task in the magazine Water Life (Volume 9, No 3)  in 1954 for repeating duff information on how to rear young terrapins. But the message was slow to get out and failed to appear in any of the British books on reptile keeping. Many pet shop/fishkeeping owners were in complete ignorance until magazines began to carry articles and information passed by way of mouth on just what equipment and food were needed to keep these animals successfully.

I must know make a sideways leap because we often forget most scientists setting out to be just that went—and perhaps still go—to university without ever having seen a scientific paper. Having to wade through long and tortuous papers and reviews for evenings on end came something of a shock. I supposed I was more fortunate than most because I had joined, at the suggestion of George Boyce, the British Herpetological Society in 1961. The subscription was modest and its journal was posted to members. It has to be said that the papers in the journal at that time were of highly variable quality but the problem in those days was to get sufficient papers to publish not on what percentage had to be rejected. But one which I think, with hindsight, influenced me greatly was entitled, ‘The care of young red-eared terrapins (Pseudemys scripta elegans) in the laboratory’. There were proper scientists describing how they had developed a protocol for keeping terrapins in terms of such factors as temperature, light, ultraviolet radiation/vitamin D, food and calcium supplementation. It showed me that a bit of science and a bit of empiricism could make it possible to keep animals successfully. The authors were Brian Blundell Boycott and M.W. Robins.

Brian Boycott FRS
from Biographical Memoirs
(see below)

Brian Boycott (1924-2000, elected FRS 1971) was a neuroscientist. He got a first degree in zoology the hard way—the very hard way—by part-time student at Birkbeck College, London while working to support himself. His first job was as an animal attendant at the National Institute of Medical Research, then in Hampstead, so he was ideally placed later to have both the experience and knowledge to find out how to keep animals in optimal conditions. His biographer, Heinz Wässle, wrote:

He learnt animal care the hard way and, more importantly, he was exposed to people with no academic ambition or background, to people who had sets of values and motivations different from those he had experienced. In retrospect this experience left its traces on his character. Brian socialized easily with people from greatly different backgrounds. Forty years later, at the Max Planck Institute in Tübingen, he became a good friend of Herr Baur, one of the people who worked in the animal house. Herr Baur owned a small farm with a vineyard and produced his own bread, delicious sausages, excel- lent wine and apricot brandy. Every so often Brian pretended that he was not hungry when the members of the laboratory went for lunch. Instead he secretly enjoyed a frugal lunch with Herr Baur in the animal house…

There must have been a realisation that with the ready supply from the USA young terrapins could be ideal candidates for some research. Boycott and Guillery used them to study memory. Similar advice on the care of terrapins in in the laboratory world to that formulated by Boycott and Robins was being promulgated in the U.S.A. and in Britain by the late 1950s.

Later, in the 1960s, Dr Edward Elkan (1895-1983), the father of reptilian pathology, investigated the  ‘eye disease’ of small captive terrapins. He found that the effects were widespread throughout the body and due to the lack of Vitamin A in the diet.

Edward Elkan
(from here)

Eventually, after what Elkan described as an ‘annual holocaust’ of imported animals, the word spread amongst amateur herpetologists and then to pet owners and pet shop owners. Terrapins could be reared to adulthood.

But then another problem was recognised. The majority of hatchling terrapins were hatched on ‘turtle farms’ in the southern states of the USA where they and the adults were fed on the waste from chicken processing factories. Salmonella was rife in chickens and so infection was passed to the terrapins and thence to the mouths of children and adults handling the animals or touching the water in which they were housed. While each outbreak of Salmonella from terrapins affected the market for a time, the trade remained vast especially during the Mutant Ninja Turtle craze.

No good turn goes unpunished for now pet owners throughout the world had the knowledge and the products to rear terrapins to adulthood. But there is a lot of difference between the cuteness of a baby terrapin and that of an adult the size of a plate. They may bite; they eat a lot of food and the water soon becomes foul. Many people in Northern Europe found they could no longer house their pets and zoos were inundated with cast-offs. Then, because there was no way to get rid of unwanted pets, they were released into ponds, reservoirs, rivers and streams. Fortunately, in Britain, for example, the temperatures are too low for successful hatching of eggs in the wild and like most of Northern Europe have escaped the long-term consequences of their release even though they live for decades. By contrast, in warm places like Hong Kong, Red-eared Terrapins have become an important invasive species. Not only is there a very large urban population keeping pets and releasing them when they outgrow their tank, but Buddhists have released them in large numbers in order it is said to bring good karma. There are now Red-eared Terrapins (now renamed Trachemys scripta elegans) over the place: reservoirs, fish ponds and large populations in the parks on Hong Kong island. The local relatively common species has declined.

A number of countries have acted to limit the movement of young terrapins from and within the USA, starting on public health grounds after the Salmonella scares but now because of the potential and demonstrated damage to native fauna. For example, the EU for example banned the import, sale or transfer of ownership of Trachemys scripta in 2016. But the trade in Hong Kong, Singapore and much of the rest of the world where imported terrapins have already or have the potential to cause damage continues.

Over a period of thirty years, a solved animal welfare problem morphed into an unforeseen conservation blight.

Boycott BB, Guillery RW. 1962. Olfactory and visual learning in the Red-eared Terrapin, Pseudemys scripta elegans. Journal of Experimental Biology 39, 567-577.

Boycott BB, Robins MW. 1961. The care of young red-eared terrapins (Pseudemys scripta elegans) in the laboratory. British Journal of Herpetology 2, 206-210.

Elkan E, Zwart P. 1967. The ocular disease of young terrapins caused by vitamin A deficiency. Pathologia veterinaria 4, 201-222.

Wässle H. 2002. Brian Blundell Boycott. 10 December 1924-22 April 2000. Biographical Memoirs of Fellows of the Royal Society 48, 51-68.

A Jock Marshall story I had forgotten

Stories of the exploits of ‘Jock’ Marshall (1911-1967) when he was Reader in Zoology at Barts in London and later in Monash University abounded in zoological academia in the 1960s. Even before Brian Lofts (1929-2015) arrived in Hong Kong in 1967 from Marshall’s old department at St Bartholomew’s Medical School in London, there were stories of his visit in the late 1950s. But one which Brian recounted I had forgotten until reminded of it in Jock Marshall - One Armed Warrior by Jane Marshall. This biography appears only to be available online here.

One year there was a very pompous ceremony at the University of London - the Queen Mother, as Chancellor, was holding a reception and the red carpet was stretched out for the hierarchical heads to follow Her Majesty into the building while we lesser members waited to follow on. Jock spotted Sir Gavin de Beer emerging from his limousine and setting sail up the red plush. As he came abreast of us he noticed Jock - 'Ah Marshall' he intoned - 'Ah Sir Gavin' replied Jock 'Sober I see’.

Sir Gavin de Beer (1899-1972) was Director of the Natural History Museum from 1950 until 1960. The Queen Mother was Chancellor from 1955 until 1980. Marshall left London for Australia at the end of 1959.

Another Orang-utan species? I doubt it too. I strongly doubt it

Orang-utan in Borneo
Orphaned animal photographed in 1999

No sooner had I written the last post on ‘taxonomic inflation’ than the media were sparking with news of a new species of orang-utan from Sumatra. I read the BBC News and The Times versions and found the claim unconvincing. I was just in the process of looking up the original paper when Jerry Coyne’s and Greg Mayer’s excoriating criticism—and of the ‘phylogenetic species concept’ in general—of the claim pinged into my Inbox. I will not repeat it since you can read it here on Jerry Coyne’s Why Evolution is True website. Make sure you read the comments as well.

Coming after a similar paper on splitting the giraffe into four species (again covered by Jerry Coyne here) published in the same journal (which much have referees or editors sympathetic to, or uncritical of, the phylogenetic species concept), I am particularly concerned that such claims, indeed any claims, are parroted uncritically by the news media and thus presented to the public as established fact. Science by hyped press release is not promoting the public understanding of science; the reverse in fact.

The ‘splitters’ of existing species appear to think that they are advancing the cause of conservation but they may be doing harm, as Shai Meiri and Georgina Mace warned ten years ago. Others have noted that in attempting to conserve species, splitting into ‘pseudo-species’ using the phylogenetic species concept may do more harm than good. By insisting on breeding each form separately (as is being done right now with the Bornean and Sumatran ‘species’ of orang-utan which were split earlier) zoos may be reducing the genetic diversity of already inbred captive populations, thereby decreasing the chances of survival should a re-introduction programme into a slightly-changed or degraded habitat be needed in the future on either of those islands.

The question of what constitutes a species goes on and on and there is no simple answer but it seems to me and to many others that the phylogenetic species concept is deeply flawed and that if the same arguments are applied to Man, then our species too must be split and split and split again. The modern molecular methodology applied to determine genetic lineage must be very seductive and there is no argument on the technical excellence of much of the work. However, I suspect it is another case of too much ‘molecular’ and not enough ‘biology’.

So, for the record I will continue to refer to the Orang-utan as Pongo pygmaeus whether it be from Borneo or Sumatra and to the Giraffe as Giraffa camelopardalis wherever in Africa it may be from. There is no need to be a sheep in the cinderella world of taxonomy.

Reticulated form of the Giraffe, Northern Kenya 1991

Masai form of the Giraffe, Kenya 1991

‘For the survival of the species’: The mismatch between evolutionary biology and conservation biology...and 'taxonomic inflation'

'Jock' Marshall
from here

In the 1960s there was a board for newspaper clippings, notices and other ephemera on the corridor wall of the old zoology floor in the now-demolished Northcote Science Building at the University of Hong Kong. At the top was a cutting from an Australian newspaper reporting an interview with the larger-than-life Professor Alan John ‘Jock’ Marshall (1911-1967) then at Monash University in Melbourne. The clearly shocked journalist reported words to the effect that Marshall did not care what happened to individual animals; what did concern him was conserving species and if that meant some individuals dying in the process then so be it.

That, in a nutshell, describes the fundamental mismatch between evolutionary biologist’s view of species compared with that of the early conservation movement and hence, because of the publicity given to conservation activities, that of the public. So we have, on the one hand, biologists wincing when they hear ‘for the survival of the species’ in terms of natural selection while at the same time conservationists talk of their work ‘for the survival of the species’.

Early conservation efforts were seen as direct threats to large animals and in terms of getting the public and politicians engaged with he problem there is nothing so persuasive as a member of the charismatic megafauna. The World Wildlife Fund’s choice the Giant Panda is the most famous example. While there were—and still are—direct and major threats to the survival of individual species, the poaching of rhinoceroses being a prime example, the question of preserving habitats (or whole ecosystems, although I hate the term because it is misleading) tended to be put to one side. If you can conserve the large species, then there will be sufficient habitat for the smaller ones to be protected as well.

However, when it came to national conservation politics legal protection was often based on a species and not on a habitat. Across a wide geographical area, local extinctions from habitat loss or hunting were possible because the species there were either not sufficiently endangered or represented a very small proportion of the total population of the species. So, the pressure was on to increase the number of species by elevating geographical variants (often termed, probably unwisely, as subspecies) to the status of full species. But not only do conservation efforts benefit (if only at first sight) by increasing the number of species. Birders of the tick-list variety just thrive on species being ‘split’ and the tour companies are always at pains to point out the chances of seeing a a new ‘split’ in a particular area. The tourism industry also loves a distinctive name for their familiar animal. ‘This is Thornicroft’s giraffe, madam’ said the guide in Zambia who was surprised when madam replied, ‘Just a giraffe with a geographically distinctive pattern’.

The whole process of increasing the number of species by deviating from the biological species concept has been called ‘taxonomic inflation’. The increase is not new; some taxonomists of old split species ad nauseam but after dismissing the nonsensical claims there were reckoned to be 4,659 mammals in 1993. By 2005 that number had risen to 5,418, not as explained by Shai Meiri and Georgina Mace in their 2007 paper, by an increase in the discovery of new species but by the splitting of existing species. With mammals, that splitting has occurred to the greatest extent in Africa where a species may have a widespread distribution.

Meiri & Mace continued:

Most of these recently described species are allopatric or parapatric (i.e., with ranges that abut but do not overlap) populations, separated by barriers such as rivers. Given a barrier to gene flow, the accumulation of genetic and morphological differences is expected and may be of limited biological importance. It seems, however, that many recent taxonomic studies regard the presence of allopatric populations as an indication that speciation has occurred. We suggest that stronger evidence is needed to show that populations are sufficiently distinct to merit specific status. This evidence should be capable of discriminating genuine ecological and evolutionary distinctiveness from minor differences that could result from geographic isolation.

I am not going into the various species concepts here but the taxonomists who do such splitting rely on using genetic analyses to identify different lineages. Some—the ‘splitters’—then argue that if groups of animals show distinct genetic lineage then they should be treated as different species, regardless of the fact that morphological differences are minor or that members of one lineage recognised those of anther as being of the same kind and would breed with them if given the chance and do do so in captivity.

While ‘new’ species may at first sight be an attractive proposition for those seeking the input of conservation resources, Meiri & Mace argued that with limited funding, resources could be diverted from a really important projects and that splitting species does not necessarily have conservation value. They also supported the policy of supporting species ‘across their ranges, perhaps favoring phenotypically distinct populations or geographically isolated subsets so as to fully conserve variation’.

Have those lessons so well spelt out by Meiri and Mace been learnt? Was madam right about Thorncroft’s giraffe?

Meiri S, Mace GM. 2007. New taxonomy and the origin of species. PLoS Biol 5(7): e194. doi:10.1371/journal.pbio.0050194