Monday 26 September 2022

A new paper on the vast trade in Tokay Geckos in general and Hong Kong in particular

The numbers of some species of wild animal traded defy the most vivid imagination. I read, in a new paper:

About three million tokay geckos per year were exported from Indonesia from 2015 to 2021, all dead and dried, with an export record of 5,974,550 in 2022.

For how long populations in the wild can be sustained, not just in Indonesia but in other south-east Asian countries from which Tokay geckos are exported, is open to question. The dried geckos are sent to China for human consumption in traditional Chinese medicine.

Some idea of the size of the market for Tokay Geckos (Gekko gecko) in Hong Kong was brought home to me about 20 years ago. Outside a medicine/food importers were bags of goods waiting to be moved inside. Amongst the interesting aromas which surround such establishments were sacks full of dried geckos. Each must have contained several thousand adults.

The recent paper tracks, using one mitochondrial gene, the origin of the geckos imported into Hong Kong. However, Hong Kong is interesting in that there is a wild population. In addition, live geckos were and still are imported both for traditional medicine and for sale in pet shops, although in comparison with the former, the numbers involved must be very small. Such is the concern with the volume of imports that the Tokay Gecko has recently been afforded protection under the Hong Kong Protection of Endangered Species of Animals and Plants Ordinance. Since 2019 it has been listed as CITES II: a species for which international trade should be controlled.

Shopkeepers asked in 2020 about the origins of the geckos they were selling reported China, Thailand and Vietnam, responses borne out by genetic analysis. They said that Indonesian geckos had been but were no longer imported. 88% of shopkeepers believed Tokay geckos to be farmed.

I realised as I read the paper that there must be historical information on where the live Tokay Geckos intended for human consumption in Hong Kong had been collected in the past. When we arrived in Hong Kong in November 1965, K.W. Chiu was working on the skin of Tokay Geckos. He was working for a PhD with Paul Maderson who had started the work in Hong Kong in 1962 but who had moved to the USA earlier in 1965. The geckos, intended for human consumption, were bought from the local snake shop. Suddenly the supply ceased, possibly because of disruption caused by Mao’s ‘Cultural Revolution’ and Chiu needed more in order to complete his work. A letter was sent to the British Embassy in Peking (now pinyinised to Beijing) asking the scientific attaché to help since it was known the animals came from southern China. I cannot remember what happened next but more geckos were secured.

I thought I would see if I could find any mention of where in China the 1960s geckos came from by searching some of the Maderson & Chiu papers. I quickly found the answer: Kwangsi now known as Guanxi Province. Whether Guanxi was then, and is now, the area of origin of all the geckos or whether it was a gathering point of geckos traded from neighbouring Vietnam and nearby north-east Thailand and Laos I do not know but in the genetic analysis these area loomed large and it would seem to me the trade in Hong Kong still relies on traders and trade routes that have endured at least since the end of the Second World War.

However, there is a complication. The new paper treats two morphs (black-spotted and red-spotted) as geographical distinct subspecies (G. gecko reevesii and G. g. gecko). By contrast, the IUCN Red List follows a 2011 paper in assigning the two forms species status and thereby resurrecting Reeves’s Tokay Gecko, G reevesii named by John Edward Gray of the British Museum in 1831. Therefore it is difficult to knowing what occurs where, Guanxi for example, when reading different accounts. However, the IUCN report does state that most records of G. gecko from Nanning, Guanxi are thought to be of animals that had escaped from farms. If—as seems likely—there are gecko farms in Guanxi then there may be all sorts of genetic admixture, just as in the case of Chinese giant salamanders.

The new paper discusses the effect of trade on populations in the countries of origin of Tokay Geckos and on the effect on accidental or intentional releases of live animals in the regions to which they are imported. The authors also consider the origins of the Tokay Gecko in Hong Kong—a topic to which I shall return.

Dried Tokay Geckos in a Chinese medicine shop in Hong Kong
This photoraph taken in 2010  by istolethetv
<>, via Wikimedia Commons)
is interesting in that it shows the red-spotted form, less common
than the black-spotted form in the Dufour et al. survey.

Dufour PC, Miot EF, So TC, Tang SL, Jones EE, Kong TC, Yuan FL, Sung Y-H, Dingle C, Bonebrake TC. 2022 Home and hub: pet trade and traditional medicine impact reptile populations in source locations and destinations. Proceedings of the Royal Society B 289:20221011 

Chiu KW, Maderson PFA. 1980. Observations on the interactions between thermal conditions and skin shedding frequency in the Tokay (Gekko gecko). Journal of Herpetology 14, 245-254.

Friday 23 September 2022

Two feral birds (Black Swan and Canada Goose) and two feral mammals in one morning

Two species of feral birds loomed large at the mouth of the Doon on 8 September just before the announcement came that the Queen had died. Both species are native to Commonwealth countires from opposite ends of the world. First, offshore was a large flock of Canada Geese (Branta canadensis). They seem to be present in much greater numbers than, say, 10 years ago. Second, feeding in the freshwater outflow were two Black Swans (Cygnus atratus). Native to Australia they are the result of escapes, like the Canada Geese, from waterfowl collections. There are now small - as yet - breeding populations in UK.

Black Swans in the mouth of the Doon, Ayrshire
8 September 2022

Part of a flock of Canada Geese off the mouth of the Doon, Ayr
8 September 2022

Further evidence of introductions during the the anthropocene as I arrived back home: Rabbits (Oryctolagus cuniculus) and a Grey Squirrel (Sciurus carolinensis) in the garden.

Tuesday 6 September 2022

A reminder of how Raymond Cowles and Charles Bogert changed how the world viewed body temperature regulation in reptiles

An offprint for sale caught my eye. Shortly afterwards I had my first comfortable look at an important piece of research published in wartime USA that I had quoted in my final-year student seminar in February 1965. I say comfortable because all I had then was an incomplete pre-xerox photocopy that was difficult to read. After I read the paper and looked at the photographs, I looked up the authors both in Contributions to the History of Herpetology and on Wikipedia. Showing how appallingly bad many zoologically based articles on the latter are, the most important work of the two authors does not even get a mention.

Raymond Bridgman Cowles (1896-1975) and Charles Michill Bogert (1908-1992) found from their studies of desert lizards that the poikilothermic animals, usually described as ‘cold-blooded’, are  not simply at the same temperature as their surroundings. Instead, by day they use behavioural mechanisms to achieve and maintain a preferred body temperature. When cool they move into, and orientate their bodies towards, the sun. When too hot, they move into shade and/or into burrows. Later, the preferred body temperature of a particular species was shown by Paul Licht to correspond to the optimum temperature for the activity of key enzymes in the tissues.

Cowles and Bogert’s research was enormously influential not only in changing the prevailing views of how poikilothermic animals work but also in opening up a new field of physiological ecology. Indeed Cowles changed the nomenclature.  Poikilothermic (i.e. variable body temperature) was taken to imply that body temperature was not regulated while homoiothermic was the term used for the internally regulated constant body temperature of birds and mammals. He argued that the term ‘ectothermic’ for animals such as reptiles that rely on external sources of heat to maintain their body temperature was more appropriate, with ‘endothermic’ for mammals and birds which generate their own body heat.

Raymond B Cowles
from Contributions to Herpetology
see below

Cowles started the whole thing off. He was born to an American missionary family in South Africa. There, as a boy, he developed an interest in birds and reptiles and back in the USA his PhD thesis was on the life history of the Nile Monitor. Appointed to the University of California at Los Angeles (UCLA) in 1929 he became interested in the extinction of the dinosaurs. He developed the unconventional idea, after seeing the work of two friends on the importance of body temperature on the activity of reptiles at night and on the heat tolerance of lizards and snakes, that dinosaurs were wiped out not by a fall in temperature at the end of the Mesozoic but by a rise. He realised that he should investigate thermoregulation in reptiles both in the field and in the laboratory and to that end established a field station near Indian Wells in 1939.

As well as his work in physiological ecology, Cowles was horrified by the effects of over-population and campaigned vigorously. He saw the effects when he returned in the 1950s to the valley in South Arica where he had lived as a boy. The land was over-grazed, barren and ripe for erosion and flooding. I find astonishing the fact that his trenchant views on the growth of the human population caused him to become unpopular—even a pariah—in his own institution and among the general American public.

Cowles remained at UCLA from 1939 until his retirement in 1962; thereafter he worked at the University of California in Santa Barbara.

Charles M Bogert
from Contributions to Herpetology
see below

Charles Bogert was a student of Cowles at UCLA in the mid-1930s, and like Cowles had wide interests in natural history. By the time he was collaborating with Cowles on thermoregulation in reptiles he was at the American Museum of Natural History in New York. Unable to afford progression to a PhD at UCLA, he had been appointed as assistant to Gladwyn Kingsley Noble in 1936. On Noble’s death at the age of 46 in 1940, Bogert was appointed to head the herpetology department. There he continued the classical ‘museum style’ systematic studies but continued with laboratory and field work in a number of areas, most notably on frog vocalisations and their biological significance. In 1966 UCLA awarded him an honorary LLD. He took early retirement in 1968, continuing to write but a series of strokes from 1988 and severe arthritis debilitated and depressed him. He killed himself in 1992 at home in Santa Fe, New Mexico.

It has been a pleasure reading Cowles and Bogert’s seminal paper which they described as a ‘preliminary study’. It described the first four years of their work  in the Coachella Valley which they described as ‘a desert of extreme heat and aridity, characterized by sporadically abundant annual, and scanty perennial vegetation’. The style of the publication, which appeared in the Bulletin of the American Museum of Natural History, is more discursive than that of a scientific paper with photographs of the terrain, experimental housing and some of the animals they studied.

Much as been added over the 80 years since Cowles and Bogert were busy in the Coachella Valley but some fundamental questions still remain. For example, although some ectotherms may achieve their preferred body temperature for part of the day, they are still poikilothermic—their body temperature does vary over the course of a day. Since temperature affects all chemical processes, then there are implications for such physiological mechanisms as the internal biological clock, for processes like memory and the action of hormones. In addition, questions of ectothermy and endothermy in dinosaurs—the problem that first attracted Cowles to the thermal physiology of desert reptiles—are still a hot topic.

Cowles RB, Bogert CM. 1944. A preliminary study of the thermal requirements of desert reptiles. Bulletin of the American Museum of Natural History 83, 261-296.

Anon. 2014. Cowles, Raymond B (1896-1975). In Contributions to the History of Herpetology (Volume 1, revised and expanded), Edited by Kraig Adler, pp 116-117. Society for the Study of Reptiles and Amphibians.

Anon. 2007. Bogert, Charles M (1908-1992). In Contributions to the History of Herpetology (Volume 2), Edited by Kraig Adler, pp 178-180. Society for the Study of Reptiles and Amphibians.

Turner JS. 1984. Raymond B Cowles and the biology of temperature in reptiles. Journal of Herpetology 18, 421-436.