Wednesday, 8 November 2017

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

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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.