Sunday 4 November 2018

Joan Procter. Her Reptile House at London Zoo and Reptilian Thermoregulation

It is only when one reads the detail of Joan Procter’s Reptile House at London Zoo that one realises she was decades ahead of her time in terms of knowledge of the thermal requirements of reptiles. The Reptile House opened in June 1927. Apart from its ‘aquarium-principle’ lighting, crowd circulation and safe-handling area for venomous snakes, the spectra of both natural and artificial lighting were specified while additional heat was supplied to different places of the cages thus creating a temperature gradient which allowed the animals to bask and raise their body temperature above that of their surroundings.

In Joan Procter’s own words when describing how the Komodo Dragons were housed and how they had lived in the new Reptile House for 18 months:

They live in a large enclosure of natural shingle and soil, planted with living palm-trees, and provided with a cave, rocks, and a swimming-pool. A great deal of care has been exercised to provide proper climatic conditions. The roof is of Vita-glass, transparent to ultra-violet light, and Vita-lamps for artificial sunlight are installed together with two large flood-light lamps. Dull-heat radiators of the beam type are also fixed, and all this apparatus, which is invisible to the public. is protected by massive steel bars. Further, the rocks themselves are electrically heated with a type of black-heat radiator let into the actual rock, and controlled, together with the air-heaters by a thermostat, which in turn is governed by a fool-proof warning system. The light and heat are chiefly focussed on a large rock in the centre of the enclosure, and, as the dragons immediately discovered this, they are usually to be seen sunning themselves upon it.

Those who know anything about reptiles will recognise this as a throughly modern way of keeping lizards. As I pointed out in a previous article the Vita glass was to let ultraviolet rays in sunlight reach the animals. Her ‘Vita-lamps’ were actually ultraviolet-emitting lamps with Vita glass filters to block just the very short wavelengths which experiments had determined were deleterious.

Previously, reptiles kept in temperate climates were kept in accommodation heated to the temperature of a tropical shade environment. Most had no opportunity to bask and raise their temperature above the ambient. The science of thermoregulation in reptiles really only took off in the 1940s and the concepts like ‘preferred body temperature’ and  ‘behavioural thermoregulation’ developed. Thus while reptiles are indeed cold-blooded they were found able to maintain body temperatures above that of their surroundings during the hours of daylight by shuttling between the heat of the sun and the relative cool of the shade. Komodo Dragons have been shown, comparatively recently, to follow that pattern.

The preferred body temperature was later shown to be that which is optimal for biochemical processes within the body. Reptiles not allowed to achieve their preferred body temperature, even though kept in warm ‘tropical’ daytime air temperatures, were function sub-optimally. It is not surprising that such animals are lethargic, their immune system left unable to cope with infection and infestation, do not breed—and do not survive for very long. Reptiles, particularly larger ones, take a long time to die.

Joan Procter was aware that she had designed accommodation for Komodo Dragons that was superior to that elsewhere. She quoted from William Douglas Burden’s book Dragon Lizards of Komodo (see my article on the Burden expedition to Komodo here):

     …We hear of specimens taken to New York* that “it was painful to see the broken spirited beasts that barely had strength to drag themselves from one end of their cage to the other.”     ‘’"SureIy it is not all a matter of diet and change of climate... Perhaps…Varanus komodoensis, in order to survive, demands the freedom of his rugged mountains.” ...,but our specimens are perfectly happy in captivity, are attached to their keepers and their friends, and are putting on a great deal of weight.

I think we can take that as London 2: New York 0, 1928 style.

This photograph of a small boy and a Komodo Dragon may have been
taken in the original accommodation in the Reptile House in London
Zoo in 1932. Joan Procter and the keepers always seemed keen
to demonstrate how tame the Dragons had become

The heating and lighting equipment was not ‘off the shelf’. The General Electric Company Ltd (not to be confused with the American company of the same name) had research and development labs at Wembley. The Times (15 June 1927) in describing the new house reported:

The very elaborate electrical installation devised by the Research Department of the General Electric Company to meet the special requirements forms an achievement in electrical installation which is unique, and cannot be described in detail here. It may be said, however, that the installation has approximately 20 miles of electric cable for the heating system and 12 miles for the indicators and tell-tales, and that some of the compartments have up to 200 electrical connexions. The wiring for lighting is almost equally elaborate.

Miss Procter wanted material for the walls that could be cleaned. She therefore had the theatrical scenic artist, John Bull, use car enamel that would be resistant to scrubbing. I cannot find a photograph of any of the scenes painted on the walls of the cages—perhaps a good job since I utterly loathe naturalistic painted backgrounds.

It is clear from contemporary diagrams that the Komodo Dragons were kept in the large enclosures at the southern end of the Reptile House, used, ever since I first went to the Zoo in the 1950s, to house crocodilians. Their glass roofs can be seen in Google Earth—just a short distance away from the new housing for Komodo Dragons.

This Google Earth View of the Reptile House shows the windows
above the cages where the Komodo Dragons were housed. Vita
glass was installed originally. Has it survived?
The new enclosure covered in plastic is the current housing
for Komodo Dragons

It is easy to criticise—ninety years after it opened—aspects of the Reptile House. The compartments for large snakes seem of the wrong proportions, for example. The domestic architect but President of RIBA, Guy (later Sir) Dawber (1861-1938), who took Joan Procter’s very detailed plans, made them buildable and added the external features seems to have missed a few tricks. The sides, especially the western elevation which forms one side of the alley between the equally depressing edge of the Mappin Terraces, are devoid of life. Guillery suggests the outward-facing cage on the eastern side (which often used to house interesting chelonians and is the only relief from the drabness) was inserted later. Dawber also designed—again from a detailed layout by Joan Procter and Chalmers Mitchell—the exterior of the nearby main entrance to the Zoo in the same Italianate style used by earlier architects. I sometimes wonder if Dawber took umbrage at the minor role he was accorded by the Chalmers Mitchell publicity machine; he did not attend the opening of the Reptile House.

But Joan Procter’s house was clearly a great leap forward for the Zoo. But there was still much to learn since reptiles and amphibians died in large numbers after importation. Even the best conditions will not reverse the effects of the stress of capture, storage in unsuitable accommodation and then long sea journeys at temperatures below the optimum together with under- and/or mal-nutrition. Real advances, other than air transport, in how to keep reptiles, other than the ‘easy’ species, would not come for another four or five decades.

I can't resist showing one of my photographs of these wild Komodo Dragons
taken in 2016


*These Komodo Dragons in New York seem to have been forgotten by historians. Their arrival in USA is usually given as 1934, Washington.

Guillery P. 1993. The Buildings of London Zoo. London: Royal Commission on the Historical Monuments of England.

Peaker M. 1969. Some aspects of the thermal requirements of reptiles in captivity. International Zoo Yearbook 9, 3-8. Zoological Society of London. London: Academic Press. 

Procter JB. 1928. On a living Komodo dragon Varanus komodoensis Ouwens, exhibited at the Scientific Meeting, 23 October 1928. Proceedings of the Zoological Society of London 1928, 1017–1019.

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