Just when we were convinced that George was going to starve himself to death, Shep had an idea. He fetched a handful of fat garden snails and tossed them into George’s pond. George, who had been sitting on a tree trunk at the back of the cage looking very regal, eyed this floating frothing largesse with his head on one side. Then he came down to the pool, slid into the water, and nosed at a snail, while we watched hopefully. Delicately he picked up the snail in his mouth and, throwing back his head, allowed it to slide to the back of his mouth. Now that his mouth was open I could see that he had the most astonishing teeth I had ever seen in a lizard: teeth that were, of course, perfectly adapted for eating snails. Those in front were fairly small, pointed, and inclined slightly backwards. These were the grasping teeth, as it were. Once they had hold of the snail, the lizard threw back his head so that the mollusc slid and rested on the teeth at the back of the mouth. These were huge, shoebox-shaped molars with carunculated surfaces which looked more like miniature elephants’ teeth than anything else. With the aid of his tongue, George manoeuvred the snail until it rested between these ponderous molars, and then closed his jaws slowly. The snail cracked and splintered, and when he was quite sure that the shell was broken he shifted the whole into the centre of his mouth and, by careful manipulation of his tongue, extracted all the bits of broken shell and spat them out. Then the smooth, shell-less body of the snail was swallowed with every evidence of satisfaction. The complete process took about a minute and a half, after which George sat there for a bit, licking his lips with his black tongue, and musing to himself. After a time he leaned forward and daintily picked up another snail, which he dispatched in the same manner. Within half an hour he had eaten twelve of these molluscs, and we were jubilant, for, having now discovered George’s preference, we knew there would be no more difficulty in keeping him.
It is always a relief when a reptile starts to feed itself, for if it refuses food for a certain length of time it has to be force-fed, and that is a tricky and unpleasant job. Many of the constricting snakes refuse food on their arrival, and have to be force-fed until they have settled down, but it is not an operation one relishes, since, with their fragile jaws and teeth, it is very easy to break something and thus set up an infection in the mouth. I think the worst force-feeding job we ever had was with a pair of young gavials, or gharials. These are Asiatic members of the crocodile family, and in the wild state feed on fish. Instead of the strong, rather blunt jaws of the alligators and crocodiles, the gavial’s jaws are long and slender, resembling a beak more than anything. Both the jaws and the teeth are fragile, the teeth especially so, for they appear to fall out if you look at them. In consequence, when our two young gavials arrived and steadfastly refused all food, including live fish in their pond, our hearts sank, as we realized we would have to force-feed them. The process was tedious, protracted and difficult, and had to be done once a week for a year before the gavials would feed on their own. First, you take a firm grip on the back of the creature’s neck and his tail. Then you lift him out of the tank and place him on a convenient flat surface. Whoever is helping you then slides a flat, smooth piece of wood between the jaws at the back of the mouth, immediately behind the last teeth. When the jaws are prised a little apart, you slightly release your grip on the reptile’s neck and slide your hand forward, push your thumb and forefinger between the jaws, and hold them apart. This is generally much easier than it sounds. The other person then arms himself with a long, slender stick and a plateful of raw meat chunks or raw fish. He impales a piece of meat or fish on the end of the stick, inserts it into the reptile’s mouth, and pushes it towards the back of the throat. This is the tricky part, for in all members of the crocodile family the throat is closed by a flap of skin; this arrangement allows the creature to open its mouth beneath the surface without swallowing vast quantities of water. The food has to be pushed past this flap of skin and well down into the throat. Then you massage the throat until you feel the food slide down into the stomach. As I say, it is a tedious task, as much for the gavial as for you.
By and large, the creatures that seem to cause the least trouble in the reptile house are the amphibians. They usually feed well, and they do not seem to suffer from the awful variety of cankers, sores, and parasites that snakes and lizards contract, though I must admit they can come up with one or two choice complaints of their own on occasion, just to enliven things for you. The pipa toads were a good example of this. These extraordinary creatures come from British Guiana, and look, quite frankly, like nothing on earth. Their bodies are almost rectangular, with a leg at each corner, so to speak, and a pointed bit between the front legs that indicates where the head is supposed to be. The whole affair is very flattened and a dark blackish brown colour, so the creature looks as though it had met with a nasty accident some considerable time ago and has been gently decomposing ever since. The most extraordinary thing about these weird beasts is their breeding habits, for the pipa toads carry their young in pockets. During the breeding season the skin on the female’s back becomes thickened, soft, and spongy, and then she is ready for mating. The male clasps her, and as soon as she is ready to lay she protrudes a long ovipositor which curves up onto her back, underneath the male’s stomach. As the eggs appear, he fertilizes them and presses them into the spongy skin of the back. They sink in until only a small proportion of the egg is above the surface. This exposed portion of egg hardens. So inside their individual pockets the tadpoles undergo their entire metamorphosis until they change into tiny replicas of their parents. When they are ready to hatch, the hardened top of the shell comes loose, and the tiny toads push it back and climb out, looking rather like someone getting out of a bubble car.
I had once been fortunate enough to witness the hatching of some baby pipa toads, and I was anxious to see if we could breed them in the zoo. So I ordered a pair from a dealer, and on their arrival installed them in the reptile house. We kept them in a large aquarium full of water, for, unlike other toads, pipas are entirely aquatic. They settled down very well, and were soon devouring monstrous earthworms by the score. All we had to do now, I thought, was wait for them to breed. One morning Shep came to me and said that one of the pipas had apparently bruised itself on the stomach, though he could not see how this had happened. I examined the toad and discovered that what appeared to be a bruise was something which looked like a gigantic blood blister. It was difficult to know what to do. If the toads has not been aquatic and had had dry skin, I would have anointed the area with penicillin. Within twenty-four hours both pipas were dead, their bodies covered with the red blisters, which were full of blood and mucus. I sent them away for post-mortem, and the report came back that they were suffering from an obscure disease called ‘red-leg’. I had a strong feeling that this had something to do with the water in which they had been kept: it was ordinary tap water but rather acid. So I purchased another pair of pipas, and this time we kept them in pond water only. This has, so far, proved successful, and at the time of writing both toads are flourishing. With a bit of luck, I might get around to breeding pipa toads yet, unless they can think up something new to frustrate me.