As I said before, scant attention was paid to zoo diets in the past and in many zoos there is still a total lack of imagination used either in working out the diets, or in presentation. Probably the most important major breakthrough in the keeping and breeding of tropical animals came with dietary experiments and discoveries pioneered at Philadelphia Zoo under Radcliffe. His discoveries were of great importance to the keeping and breeding of wild animals.
Working with the animals at Philadelphia Zoo, Radcliffe was puzzled by the fact that, although common animals had good longevity records, they failed to breed. More delicate animals were eating well, but the mortality rate among them was high. After a lot of investigation, he discovered that while, on the surface, the diets fed looked perfectly adequate, they were lacking in a number of trace elements, minerals and vitamins. He experimented and eventually came up with a form of pellet which contained all the additives that the diets needed. These pellets were fed in addition to the normal diet and an immediate increase in successful breeding resulted, as well as a general improvement in the animals’ condition and longevity. This pioneer work was later taken up by Lang and Wackernagel at Basle Zoo in Switzerland and Radcliffe’s additive was extended in scope and improved on, with spectacular results, not the least being the successful breeding of gorillas for the first time in captivity in Europe.
When the result of the work at Basle was published, it had a somewhat mixed reception; it was described to me by one eminent English zoo director, for example, as ‘a lot of bloody nonsense, feeding animals on nothing but pills’ and by another broad-minded and go-ahead director as ‘a lot of rubbish, stuffing animals up on vitamins, instead of giving them good food’. Having lived most of my life on the continent, I lack, to some degree, that insular, blinkered smugness of character that makes the English so charmingly unique. So, overlooking the fact that this whole new process had been invented by one set of foreigners (the Americans) and added to and improved by another (the Swiss), I nevertheless felt the matter was of great importance and well worth investigating. I therefore paid a visit to the fountain-head, as it were, Basle Zoo. I was vastly impressed by what I saw and what I was told by Lang and Wackemagel and I returned to Jersey determined that we would put this new dietary system into operation as soon as possible.
We had long conferences with Mr Le Marquand, the zoo’s miller, for some of the ingredients could not be obtained easily and we had to find suitable substitutes. Finally we took delivery of the first cake, as we called it. There had been a lot of discussion as to whether the ingredients should be presented in the shape of a loaf, a biscuit, or in some other form and we had eventually decided to stick to the Basle Zoo method, which was a sort of dough-like cake, served in pieces about an inch long and half an inch wide. I had been warned by Lang that, if my animals were anything like his, they would fanatically resist the introduction of this new element into their diet. He said that he had had, in many cases, practically to starve his animals before they would even try the new substance. Now, however, they all adored it.
Lang’s prognostication proved right; our animals displayed all the symptoms of appalled horror that you would expect from a missionary to whom you had offered human flesh en casserole. We wondered, in the face of such stubbornness, whether perhaps our dough-like substance tasted different from Lang’s; since some of the ingredients were not the same was the first result perhaps unpalatable? Like a board meeting of Peek Frean, we stuffed our mouths full of the substance and compared notes. We found the cake to be pleasant-tasting with a nice nutty, biscuity flavour. It was, we agreed, very acceptable. However, our liking it was not much help. The animals did not find it palatable and that was that. There was only one thing we could do and that was to add something to the taste, to make it more attractive.
Most of the things we at first thought of would have been burnt out during the baking process. It was when we reached what appeared to be a dead end that I thought of aniseed, a time-honoured substance for baiting traps and for stealing dogs. We tried it and, to our delight, the aniseed flavour came through loud and clear. We decided, wiping the crumbs off our mouths, that the product was now delicious. To our great relief, the animals felt the same. Now it is a pleasure to watch one of the gorillas, on being handed a dish laden down with delicacies ranging from grapes to raw eggs, sift through the food with a thick black forefinger and carefully extract the biscuits, in order to eat them first with the rumbling, growling, avalanche-like noises that gorillas make as a sign of extreme pleasure.
In addition to the ape nuts, there was also a special carnivorous variant that we used to sprinkle over the meat and other foods given to such things as the lions and servals. This was of enormous value. In Jersey, a large proportion of the bull calves are slaughtered at birth or within a few days of it. Prior to our arrival on the island, this valuable source of protein was simply buried, as it was useless as veal, for the calves were too young and, moreover, had yellow fat, which, for some reason, makes it unsaleable. From our point of view this was a blessing, since it meant that we would have an almost unlimited supply of fresh meat, free. The advantage of being able to feed freshly killed meat of this sort, with the bones, skin and stomach as well, was, of course, enormous. However, we did find that the meat of these young calves did not contain the amount of nutriment, in the shape of vitamins and minerals, that was to be found in the meat of adult horses and cattle. The carnivorous mixture added to our meat provided those essential ingredients that were missing.
Diet and disease, of course, are inextricably bound up: feed the wrong diet, or one lacking in some vitamin or mineral, and you open the door to a host of diseases. A case in point was the killing malady, called cage paralysis, which, as it turned out, had nothing whatsoever to do with cages.
Among the new world primates in particular, and occasionally in those of the old world as well, you got a strange form of creeping paralysis for which there was no known cure. It was called cage paralysis because it was felt vaguely that it was caused by incarcerating animals in small cages where they could not get sufficient exercise. This was supposed to cause their muscles to atrophy. I had noticed, however, that the disease attacked monkeys kept in quite spacious quarters, which seemed to indicate that the cause might be dietary.
When I was an animal collector, this disease was probably the most widespread and serious – since apparently incurable – among captive primates. It would start very gradually and almost imperceptibly in the hips and hind limbs of the animal. The creature would start to shuffle rather than walk, and show a disinclination to move about a lot. Gradually it would lose the use of its hind limbs and the paralysis would creep upwards to immobilize the rest of the body. Long before this stage, however, the animal would probably be destroyed since, as I say, there was no known cure. While collecting in South America, I had experienced several outbreaks of this unpleasant disease among my monkeys and on my return I discussed the matter with one of the few intelligent veterinary surgeons that I knew. Competent veterinary surgeons you can find; intelligent ones are as rare as unicorns. She suggested, stressing that it was only a guess, that the disease might be due to a lack of phosphorus in the diet. We checked the diets I had been feeding and found that they contained a full complement of phosphorus. ‘Well then,’ my friend suggested, ‘it might be that they are unable, for some reason, to absorb the phosphoms.’ She suggested injecting D3, which she said would alleviate this condition. At that precise moment, there was no monkey suffering from paralysis, so I tucked the information away in the back of my mind and forgot about it.
It was not until we came to Jersey that I had a chance to try it out. We had a Patas monkey from West Africa, one of those charming, long-limbed, ginger and black animals, who was attacked by the disease and succumbed with extraordinary rapidity. In a very short time she became totally paralysed, her entire body immobile; she could still breathe and eat and drink, but only if we held he
r head up. It was then that I remembered what my friend had suggested and hastened to procure some D3. There was no precedent for its administration, but as the drug was considered harmless I gave the Patas a massive dose. She was so far gone by then that it was, almost literally, kill or cure. To my astonishment, within forty-eight hours there was a marked improvement. I gave her another, slightly less massive dose. Within the week, she was moving her limbs and within a month bounding around her cage with such vigour and joie de vivre that it seemed impossible that she’d ever been that flaccid, immobile creature on the edge of death.
The animals that were particularly prone to this unpleasant disease were the marmosets and tamarins and they succumbed very easily, because of the fragility of their make-up. The first sign of a shuffling gait in one of these animals had been a death sentence in the past. Now, an immediate dose of D3 and the animal had no further trouble. Naturally it was necessary to inject a massive quantity compared to the size of the animal and, naturally, the marmosets and tamarins took grave exception to this. However, it was for their own good and we had to do it. Now, fortunately, we can give D3 orally, so that they get it in their food. It is pleasant to know that the so-called cage paralysis is a thing of the past, for I know of no more harrowing experience than watching an otherwise healthy animal lying with death creeping up its body, and being powerless to help it.
The importance of these additions to the normal food is indicated, I think, by the figures of our breeding results. In any collection of animals the feeding is of paramount importance if you are to obtain good breeding figures and, in our case, the breeding results are probably one of the most important, if not the most important, aspects of our work. I have tried to show that feeding animals is not as simple and as straightforward as it appears. We are still very far from knowing all the answers to the dietary requirements of animals kept under controlled conditions. This is due, in the main, to our ignorance about wild diets and their composition. We know that some creatures, at certain times of the year, visit special mineral or salt licks and feed off certain fruits, berries or fungi, but we do not know the importance of this to their overall well-being. We are only just learning that the diets that we have been giving to animals, though they may be varied enough to keep the animals alive and well, may not be sufficiently imbued with the right vitamins or mineral traces. These might make all the difference to the length of time an animal lives, its general health and well-being and its breeding potential.
Realizing what an untouched field of research lies here, we have recently, with the aid of a most generous grant from the Freund Foundation in America, set up a nutritional laboratory. Our first job is to break down all our present diets, so that we know precisely what they contain. While doing this, we are going to amass as much information as possible about wild diets and their seasonal variations. Thus we will have some sort of comparison to work with and from this we hope to improve our feeding, to establish what vitamins or minerals are missing and, of vital importance, to discover the best way of including these in our diets. To this end, we are setting up an experimental nursery in which we plan to grow selected shrubs, vegetables, fruits and herbs. Obviously, if one discovers that an animal should have a certain vitamin or mineral in its diet and one can give this as a plant or fruit that the creature likes, it is a much more satisfactory way of administering it than simply by opening a bottle. Also, you can discover new herbs, shrubs, vegetables and fruits which the animals may like. These can form a useful addition even if they are of no nutritional value, for they enliven and vary the diet and, in cases of illness, can play a most important veterinary role by acting as a stimulant.
It is also necessary to learn – and we hope we shall do this eventually by field studies – at what time of the year certain things are eaten and why. Is it because the foodstuff is only available at that special time, or is it freely available all the year round, but only eaten at that particular time for some other, specific reason? The monophagus Koala bear is an example of what I mean. Its diet is restricted to two species of Eucalyptus leaf. At certain times of the year, a Koala moves from x species to y species, for the simple reason that the shoots and the young leaves of x species, when growing, contain enough prussic acid to kill.
It is vitally necessary for us to learn more about wild animals’ feeding habits, for the lack of one simple ingredient could mean the difference between success and failure. To say that animals in the wild state have some very curious food fads is no exaggeration. For example, it was known that marmosets and tamarins consumed live food in the shape of tree frogs, lizards, baby birds and eggs, as well as fruit and buds. Just recently, however, two other startling ingredients have been added to the menu; sap and, of all unlikely things, bats. The sap is obtained by the animal making grooves in the bark of branches with its teeth and then lapping up the tree juice that oozes out. The bats are captured when they are roosting in hollow trees during the day.
If it is possible that one day we may be returning captive-bred animals to the wilds, either to populate an area where they have become extinct or as an aid to a dehabilitated species, then the diet becomes of even more vital importance. To take an extreme and slightly ludicrous, though not unlikely, example: if a species of owl, seventh generation born in captivity, had been trained to eat white mice, it might well starve to death if released in the wild and found only brown mice available. Another aspect that has to be borne in mind is that the wild foodstuffs, for the most part, are provided in considerably less generous quantities than those received by the cosseted captive animal. It may well be that, before release, it would be necessary to put the animals on a preparatory diet, rather like someone training for the Olympics. These are all problems that lie in the future but, in conservation, the future has a habit of becoming the past with frightening rapidity. That is why we are already starting on this line of research.
To economize on food is a false economy. Of course there are cuts one can make. If one finds that carrots contain more goodness than hot-house grapes, one tries to feed carrots, which are cheaper. But one must never eliminate the hot-house grape completely. It serves a purpose, if only as an aperitif or an appetite stimulant. Anyone who has spent any time in hospital would agree that the food may be well balanced, nutritious and bursting with vitamins, but it still lacks that Epicurean touch that makes the taste buds, metaphorically speaking, stand up and cheer. When you are dealing with a collection of wild animals, it is essential that at all times their taste buds should be catered for.
A Multitude of Matings
‘Weasel . . Some say that they conceive through the ear and give birth through the mouth, while, on the other hand, others declare that they conceive by the mouth and give birth by the ear.’
T.H. White, The Book of Beasts
‘A comprehensive literature exists on how to manage domestic animals, dealing at length with every conceivable detail. Feeding, breeding, transmission of hereditary characters, pedigree, distribution, market value, pathology, training and so on have long been the subject of basic research and have become the specialized departments of an impressive science. On the other hand, the study of how to keep wild animals in zoos can hardly boast of even the most general outlines; all it has to show is a collection of more or less disconnected pieces of advice and some facts.’
Heini Hediger, Man and Animal in the Zoo
‘Partridge . . . Frequent intercourse tires them out. The males fight each other for their mate, and it is believed that the conquered male submits to venery like a female. Desire torments the females so much that even if the wind blows towards them from the males they become pregnant by the smell.’
T.H. White, The Book of Beasts
‘In his research on mountain gorillas living wild in the area of Kabara G.B. Schaller (1963) found a mortality of 40 per cent to 50 per cent during the first six years of life; the mortality is highest in the first year of life
. In this connection it should be remembered that gorillas only have a few enemies apart from men.’
Heini Hediger, Man and Animal in the Zoo
‘Ethel and Bernard returned from their Honeymoon with a son and heir a nice fat baby called Ignatius Bernard.’
Daisy Ashford, The Young Visitors
It may sound obvious, but the acquisition and introduction to each other of a compatible pair of animals is the first prerequisite for successful breeding. Many people consider that all that is necessary is for a male and female of a species to be confined in a cage together, but the whole business is infinitely more complicated than that. Marriage arrangements are sometimes of great complexity and, as the animal gets rarer, careful considerations of bloodlines take place that would do credit to a similar arrangement among royalty. You may go to endless expense and trouble to obtain a mate for something, only to find that the two animals hate each other on sight, or, what is probably worse, tolerate each other and settle down to a dull existence together without issue. If they take an instant dislike to each other, you at least know where you are, but if they settle down to be just good friends, you are in a quandary. Will this toleration grow into something deeper? Will this liaison have a happy ending? You find yourself asking these questions with all the earnestness of the editor of a women’s magazine when presented with a new serial.
The Stationary Ark Page 7