LETTERS TO THE EDITOR

Dear Sir,

Your editorial on `technological wizardry' (I.Z.N. 45:4, p. 190), which was prompted by Pay Pawley's article in the same edition (pp. 212–219) on the thermometer gun, touched a chord in me. For although `you read about it first in I.Z.N.', I have for many years considered it highly likely that birds were seeing markings or colours on one another that we are unable to detect. Unfortunately, I had no way to test the idea. Also, I too consider the likelihood of other technical advances being used in animal management as being very high, despite some of them possibly appearing a little unlikely at first (several older vets have told me they laughed at the idea of the projected syringe). I am sure many people have ideas they are unable to test. Here are a few of mine. The stimulation usually comes from science programmes on TV or articles in newspapers and magazines. I offer them here for possible ridicule but, more hopefully, to give impulsion to someone with the means to test them.

Firstly, the thermometer gun sounds a great invention, one that I am sure will be widely used in zoos as it becomes better known. Its limitation of not being able to read body core temperatures of animals could possibly be overcome. Conceivably, a transponder exists, or could be developed, that would function in the same way as the existing ID transponder implant chip does – the idea being that the adapted transponder would give off a reading of the animal's body temperature rather than a random digital read-out. This would then be read by a receiver. This may not be ideal for small lizards, but many other animals have enough body size to make the idea plausible.

Staying with the heat detection theme, another idea is a would-be adaptation from research into human breast cancer. Research has shown that early signs of breast cancer in women can be the development of hot spots in the breast tissue. The earlier a diagnosis of the disease is made, the more likely it is that treatment will be successful. Therefore, a method of detecting the heat spots was developed. This took the form of a specially-designed brassière with heat sensors implanted into it. It occurred to me that sensors as sensitive as that could be of great value if they could be incorporated into a harness for animals. Principally, I envision its use to be in detecting oestrus in female mammals, whose body temperatures rise and fall with the onset and decline of the oestral phases. I also wondered if there may be a chance of a tie-up here with the long-range reading of the thermometer gun and an implanted `thermo' chip such as I described above.

Another company in the U.K. has done research into basic body odour in people. They have been so successful in isolating and detecting individual body odours that they have been able to develop, around their findings, a fully computerised security system. This works on the principle that no two people have identical body odour, any more than identical fingerprints. Moreover, this basic odour cannot be masked, even by the most pungent cologne or spicy curry. I strongly suspect that research into the body odours of other species would reveal that they too have significant individual odour characteristics. This conviction was further reinforced in me after reading the item on a `primate welfare workshop', by Christoph Schwitzer and Werner Kaumanns, which also appeared in the June edition. Surely, squirrel monkeys haven't developed the degree of olfactory discrimination described for no adaptive reason. As the article says, the distinction seems likely to have `at least some informational value to them.' Why not to us too? Surely, there is potential here for the development of non-invasive techniques to determine an animal's identity by its odour, both in captivity and in the wild. Its main merit, in a routine way, would be the elimination of the stress of capture and handling that must inevitably occur at least once in an animal's life, if it is to be fitted with a collar, tag or some other mark of identification. How much easier it would be to feed an animal near a sensor that gave off a reading fifty meters away, as the target brushed past.

A further adaptation could be the recognition of chemicals associated with conditions such as illness, breeding cycles, impending parturition etc. – all invaluable information that could provide a priceless management tool. Just think, you could avoid the risk of introducing incompatible pairs, gain early clues as to what was ailing a sick animal or when to isolate a pregnant female. This could be a particular boon with wild animals who go to some lengths to mask illness or imminent parturition.

As man's olfactory sense is so poor, I think we underestimate its potential for providing information and as a diagnostic tool in many areas. In some spheres this may be excusable, but in the field of zoology, where our charges offer us examples every five minutes, it seems much less so.

Lastly, and still on the theme of identification, isn't it about time we came up with a method of identifying animals from a distance without the need to hang potentially dangerous and certainly disfiguring plastic collars from their necks, burn huge numbers into their hides, or puncture their ears with holes and tags? As birds have long been so good at deceiving us with invisible colourings, could we not adopt a similar strategy? I feel sure the international chemical industry is capable of developing dyes that are only visible under certain lights or when viewed with special optics. The dyes themselves could be painted on or applied with specially adapted pellet guns or blowpipe syringes. In many cases, the need to use unsightly and/or potentially dangerous identification methods could be reduced, if we could colour-code our animals with invisible marks.

Yours faithfully,

Richard J. Wood,

P.O. Box 64,

Seeb International Airport,

Post Code 111,

Sultanate of Oman.

Dear Sir,

I was most interested to read in the Editorial of the June issue (I.Z.N. 45:4, p. 190) about the possibility of confining animals to unfenced enclosures by means of electric shocks; but `there's neither wisdom nor folly new under the sun,' as something uncannily similar to this was brought into use in the 1930s by, of all unlikely people, Hermann Goering, Nazi Germany's Reichsmarschall. Better known as the head of the Luftwaffe, he was, apparently, genuinely interested in animals and kept a wide range of species at his home, Karinhall. The foreign mammals and birds were housed in conventional, if roomy, cages and enclosures, but a wide tract of the heavily-wooded estate was left as a reserve for indigenous fauna – chiefly ungulates – and was remarkable in being completely unenclosed. Should an animal wander too close to the limits of Karinhall, however, it activated a strident-sounding klaxon that, in theory, startled it into going back the way it had come. Just how successful it was, or if in time the more intelligent species became used to it to the extent of taking no notice, I do not know. I've small doubt, too, that it was far less sophisticated than the method described in the editorial, but when it's borne in mind that it was conceived and put into practice well over 60 years ago, it was indeed an astonishing and innovative piece of technology.

On not dissimilar lines I was also interested to read Prof. Jared Diamond's comments and deductions on birds eating soil (pp. 230–231), as this was observed and acted upon during the early years of the present century by George Jennison, the great but unfortunately now forgotten curator of Manchester's Belle Vue during what were arguably its greatest days. As a result of noticing wild birds seemingly eating soil in the grounds, he gave orders that what he always referred to as `the good earth' should be offered in small dishes alongside the usual food for a wide range of species in the collection. Many – including some highly unlikely ones – readily availed themselves of it, so it was thereafter provided on a regular basis. In the `Belle Vue Collection' in Manchester's Chetham's Library is a paper, in Jennison's own hand, in which he waxes enthusiastic about the benefits of this readily obtained substance to avian health.

Yours faithfully,

Clinton Keeling,

13 Pound Place,

Shalford,

Guildford, Surrey GU4 8HH, U.K.