Robert H. Wilson, assistant professor of industrial hygiene at the University of Rochester School of Medicine and Dentistry, makes a hobby of reptiles. He writes: "It is not easy to study reptiles in nature. Most of them are shy animals that rapidly disappear at the approach of Homo sapiens. Even in the Southwest, a veritable reptile sanctuary because of its desolation and sunny weather, one must have infinite patience to observe these animals going about the absorbing business of staying alive.

"A much more satisfactory approach is to keep them in the home. They are not good pets in the ordinary sense. You cannot teach a snake or a lizard to do much more than respond when you approach with food. The rewards come in observing at first hand the ordinary life functions of these unusual creatures. Watching a healthy snake shed its skin still fascinates me, even though enough cast skins now hang in one of my windows to obscure the view. The courting activities of some of the small desert lizards are at once comical and enthralling. And a particular satisfaction comes in raising a juvenile reptile to impressive size and health.

"If one recognizes the fact that reptiles have specialized dietary requirements, the rest of reptile-keeping is relatively simple. It is even inexpensive, provided one controls one's enthusiasm for collecting specimens. Of the 40-odd reptiles of various species in our house, we bought only four, all pet turtles from a store. The rest were acquired by gifts, trades, hatching and capture. The most important route of acquisition is the first. Once it becomes known in the neighborhood that you like snakes, your collection will grow as small and large boys appear at your door with boxes and paper bags. Trading specimens with reptile fanciers, especially those in parts of the country remote from yours, can bring in a wealth of species that you are not likely to see any other way. Capturing your own specimens has all the thrills of the hunt, and can enrich the dullest countryside.

"The art of capturing snakes is greatly simplified by the cut-down golf putter shown in the accompanying illustration [Figure 1]. With this tool it is easy to pin down the snake so that it may be taken by hand as illustrated. Another useful accessory is a net made by stitching one end of a tube of muslin to a heavy wire ring and tying the other end with a string. A fairly long handle should be attached to the wire ring. Tying the end of the net shut simplifies the problem of transferring a netted snake, particularly a biter, into a bag. The net should be deep enough so that a half-turn of the handle closes the net on itself but leaves room for the snake at the bottom.

"Snakes are caught where you find them. A slow drive down a deserted road at night will frequently turn up an amazing number of snakes, particularly in the Southwest. Turning over stones and rotted logs is also productive, but in rattler country this should not be done with bare hands; use your snake putter or a stick. Most of my snake-catching is done by the putter-and-net technique.

"Traps are not satisfactory for capturing snakes, but they are quite successful with lizards. Two kinds of trap are illustrated here. Spoiled meat inside such traps will attract those lizard species that have a well-developed sense of smell. A simple box trap is preferable for desert regions where shade is scarce, because lizards seek the shade when the sun becomes too hot for their comfort. The box may be two feet square and six inches deep. It is closed at the top with a wooden door and at the bottom with a wire screen. Two or three two-inch holes are drilled in one side about half an inch from the bottom. The trap is placed with the holes on the shady side, and jiggled down into the sand until the bottom of the holes are flush with the surface. The box is then covered with sand (except, of course, for the side with the holes). This keeps the temperature inside the box from rising too high in the hot sun. Lizards approaching from the shady side will find the holes and enter the box. Once inside, they will stay for several hours during the heat of the day. The specimens should be harvested two or three times before the heat subsides.

"Netting lizards is usually unsatisfactory because they are far quicker than the netter. The lizard is much less likely to scamper off if it is approached with a noose at the end of a trout-fishing rod. The noose can then be maneuvered over the lizard's head and pulled tight simply by raising the rod. The noose should be made of silk thread rather than nylon, because nylon tends to curl.

"Turtles that are accustomed to sunning themselves on half-submerged logs can be trapped by assembling four logs in a rectangle and suspending a net in the water beneath it. The turtles come out of the water from the outside of the rectangle, but they may depart to the inside, particularly if the turtle-trapper appears suddenly from the right direction. They can be kept from climbing out of the trap by studding the inside of the enclosure with nails that point downward at an angle. Turtle-collecting should be done with the knowledge that a number of species are protected by law. The desert tortoise, for example, is protected throughout its range, and the penalty for possessing one can be as much as $500. Eastern turtles that are protected include the box turtle and the wood turtle.

"All reptile specimens are best transported in muslin bags 18 inches wide and a yard long. The bags should have double seams so that the specimens will not become entangled in loose threads. When poisonous snakes are transported, an external tab should be attached to the bottom of the bag so that one can empty the bag without exposing oneself to a bite.

"Once you get the captive home, you must think of where to put it. A good container for small reptiles that cannot climb is an aquarium. Of course a wooden box will do as well, though it is desirable to fit the box with a glass front so that you can easily observe what is going on inside. With nonaquatic reptiles it is necessary to cover the box with a snug (but not airtight) cover. Snakes especially have a rare talent for finding a small opening. I use several different kinds of cover: wire screen, perforated masonite and occasionally glass, raised slightly from the top of the container to provide adequate ventilation. The design of the cover is governed largely by the animal inside. Wire screen is generally unsatisfactory for snakes. They have a tendency to rub their noses on the screen and injure themselves. For some of the stronger species of snake a sturdy top is needed, and masonite fills the bill. A glass cover is used when it is desirable to keep the temperature and the humidity high.

"Most discussions of reptile-keeping emphasize the importance of avoiding decorative effects in the cages, pointing out that sanitation is a problem and that the humidity resulting from the presence of plants is detrimental. I do not agree with this. Animal cages in the home should be attractive. Moreover, the animals themselves appear to feel more at home in cages that roughly approximate their natural habitat. One can divide cage climate into broad categories-for example, desert, temperate-zone region or bog-and select plants and other surroundings that are compatible. Properly managed, a reptile cage can be as decorative as the handsomest aquarium. One warning: reptiles to be placed in a decorated cage should be carefully inspected for mites. Once introduced into such a cage, mites hide themselves in crevices and are almost impossible to eliminate.

"The sanitation problem is most easily met by placing a deep layer (one to two inches) of aquarium gravel in the bottom of the cage. It is a simple matter to pick up excreta and contaminated gravel with a scoop and to replace the gravel from time to time. Many terrestrial reptiles are fond of burrowing on occasion, and aquarium gravel is a good medium in this regard because it does not pack or cake.

"The illumination of the cage is important, both for the welfare of the animals and for satisfactory viewing. Most reptiles do best at temperatures slightly above 70 degrees Fahrenheit, the desert species preferring temperatures as high as 100 degrees. I achieve good temperature-control by balancing the radiant heat of incandescent lamps against the heat loss through the sides of the cage and by whatever air circulation there may be. Reptiles govern their body temperature by absorbing heat in varying amounts from their surroundings. Incandescent lamps at the top of the cage, together with the judicious location of furniture such as rocks or sticks at various distances from the light source, permit the animals to select their own temperature conditions. It is astonishing to observe how quickly these not especially bright creatures learn that they can warm up most quickly by climbing to the highest point in the cage. When several lizards are in a cage and the light comes on after a cool night, an amusing scramble for top position usually ensues.

"An effective source of light and heat is the 75-watt spotlight lamp available in most hardware stores. The reflector of the lamp is highly efficient for both visible and infrared radiation, and incidentally lends itself to dramatic lighting effects. The radiation is concentrated, however. It is therefore important to direct it so that the animal can get out of the beam and avoid overheating. I usually mount the lamp so that the front of the glass envelope is about 10 inches from the highest piece of furniture in the cage.

"The main problem in keeping reptiles is to provide them with the proper diet. Few reptiles are vegetarians, though some turtle and lizard species will eat lettuce. The rest demand meat in various forms. Most turtles will eat any kind of meat proffered (including a bit of finger if you are not quick). Cod or ocean perch seems particularly tasty to aquatic turtles. Several of the more terrestrial species thrive on dog food, particularly Pard. It is important to remember that the aquatic turtles (all those sold in variety stores) are unable to eat when they are out of water. The turtle bowls sold with them are almost always inadequate. Such a turtle is properly kept in an aquarium measuring at least 10 inches wide and 12 inches long. The aquarium should contain six to eight inches of water, a sunning platform and an ample heat source such as the 75-watt spotlight lamp. One should be forewarned that these turtles will grow, some of them to as much as eight or 10 inches long if they are properly nurtured.

"Most of the lizards are insectivores, eating moths, flies, beetles, grubs, grasshoppers and so on. Such prey are not easy to come by in the winter, and it is almost impossible to convert a lizard to foods such as beef or fish. However, there are solutions to the problem. Meal worms can be bought in pet stores. These worms, the larval form of the darkling beetle that commonly occurs around granaries, are a splendid food for insectivores, apparently supplying all the important trace nutrients.

"Recently I have found that Russell Vance of Lincoln, N.Y., maintains a year-round supply of crickets that bids fair to revolutionize the keeping of reptiles. It is not difficult to raise meal worms in amounts sufficient for one or two small lizards, but a larger lizard can put away 75 to 100 worms a week. This calls for a rate of production that is difficult to maintain in the home. Moreover, some lizards ignore meal worms. The crickets, however, are a different story. In the first place, they are larger, so that even our fairly sizable African agamid is satisfied with three or four. Second, they do not contain so much chitin, the horny substance of the insect skeleton. If a small lizard is fed a steady diet of meal worms, the indigestible chitin of the worms may actually block its gastrointestinal tract. Crickets also seem to provide more dietary essentials than do meal worms. My lizards are all in much better health as a consequence of the shift to crickets. My one insectivorous snake, a member of the smooth green species, eats crickets to the exclusion of all other food.

"The snakes are probably the most fascinating of all the reptiles. All snakes are carnivorous. In most cases this means one must supply them with mice or rats for food, although water and ribbon snakes will eat fish (minnows or thawed pieces of frozen fish). Garter snakes can be induced to eat chopped earthworms mixed with hamburger; later they can be graduated to hamburger alone. Working as I do in a biomedical laboratory, procurement of mammalian food for my specimens is no problem. I simply set up a breeding colony of mice in an out-of the-way corner and harvest as needed. Our rat colony generally produces an adequate surplus to supply my modest needs. The less fortunate reptile-keeper, however, can doubtless make arrangements with a biological or medical laboratory for a supply of surplus rodents, usually at a reasonable cost. Breeding in the home is not recommended. It is accompanied by an odor problem that even the most tolerant wife can seldom ignore.

"Of the readily available snake species, some are more adaptable to the home terrarium than others. The list is headed by bull snakes, which are unusually docile. I have picked up wild bull snakes in the deserts of Nevada and Idaho that struggled no more than those in my cages. Corn, fox and rat snakes are somewhat more excitable, but still adapt nicely to confinement. An unusually charming little specimen is the red-bellied snake, which grows to a maximum length of 10 inches. These require a steady diet of small angleworms or garden slugs (the brown ones, not the gray), which are easily raised in leafy litter, with lettuce and chicken mash as food.

"Most of the racers and coachwhips are best left in situ. They are nervous and irritable, and they bite severely. The poisonous varieties should be left strictly alone. ( I must confess that I have a couple of juvenile Great Basin rattlers that I caught in Idaho last summer; I keep telling myself that as soon as they are big enough I shall give them to the zoo.) Although many of the pit vipers (which group includes the rattlesnakes) are attractive and interesting, the risk is severe. Moreover, not all neighbors are as tolerant and understanding as mine.

"Perhaps the most important item in reptilian diet is an adequate supplement of vitamins. Virtually all reptiles are sun worshipers, and in captivity they must have vitamin D to compensate for the lack of sunshine. My procedure, which seems to work extraordinarily well, is to include one or two drops of 'Abdec' per ounce of drinking water.

This water-soluble polyvitamin preparation appears to suit reptiles ideally. The effect of vitamins can be most dramatic. A reptile specimen that is lethargic and off its feed can become a ravening brute ready to eat almost anything one or two days after the direct administration of one or two drops of Abdec. Once the reptile is in condition, the maintenance dose in drinking water seems to be sufficient. Turtles are particularly sensitive to the lack of vitamins and should be given a direct dose every month or so.

"Reptiles can be watered in several ways, depending on the species. A snake will drink from any dish large enough to admit its head and an equal length of neck. Some lizards will drink from a dish; others, from a watering bottle. Some, such as the anoles, or 'circus chameleons,' must be watered with a dropper or by sprinkling the plants in their quarters.

"When one keeps reptiles in the home, it is difficult not to be anthropomorphic about them. Lowly though they are, reptiles are individualistic, and one cannot avoid assigning them personalities. In the final analysis, why not? Each animal has a behavior pattern that is partly instinctive but partly the result of experiences during its lifetime. To me it seems only reasonable that individuality should develop. My three bull snakes are an excellent example. All were taken at the Nevada Test Site of the Atomic Energy Commission, and they look pretty much the same. Yet there are marked behavioral differences among them. One of them, which was caught as a very young specimen, has been in captivity most of its life, and probably as a consequence has come to enjoy being handled. It rests quietly for long periods in the hands of anyone who will hold it. Another of the snakes, almost identical in appearance, was mature when taken, and although evidently satisfied with the food supply and creature comforts, has never really resigned itself to handling, preferring to wander about unconstrained when released from the cage. The third snake is intermediate between the first two; it enjoys a trip but is willing to settle down after it has investigated its surroundings.

"The challenge of keeping these animals, coupled with the opportunity to observe at first hand their functions and behavior and, above all, their remarkable adaptations to their environment, make reptile study in the home a particularly rewarding avocation. The formal background requirements are certainly minimal. I am an engineer and my biological training consists of only one year of high-school biology. I find, however, that I have absorbed an astonishing amount of biology and zoology without half trying; so much so that I am about to undertake some laboratory experiments in reptilian physiology."

R. Stuart Mackay of the University of California calls our attention to an interesting property of the "flints" used in cigarette lighters. At room temperature they are strongly attracted to a magnet, but when they are heated to 125 degrees centigrade they abruptly become nonmagnetic. In effect, they exhibit the property of bistability with respect to temperature and magnetism. Hence they may be used as the active element in novel heat engines. For example, a quantity of flints (the active material is the metal cerium ) could be attached to the bottom of a pendulum and energized by focusing a beam of infrared radiation on them at the point where they pass through the bottom of the swing. A strong magnet would also be located at this point, almost close enough to touch the metal. Once started, the pendulum would continue to swing as long as the infrared was supplied. Because the flints would be heated at the bottom of the swing, they would be strongly attracted to the magnet during the downswing and less strongly attracted to it during the upswing. Accordingly a net transfer of energy from the infrared beam to the pendulum bob would occur.

Mackay suggests that the effect can also be applied to a device for converting heat into rotary motion by fixing a number of flints to the rim of a disk free to turn on an axle. A source of heat and a magnet would be located at adjacent points on one side of the disk. A motor of this type has been constructed by Roger Hayward, who illustrates this department. According to Hayward, the motor does not run very fast, and its output is in the "flea-power" class.

"The power of the engine was so minute," writes Hayward, "that I had to fit it with a magnetic bearing to make it run at all! As an interesting demonstration, however, it is well worth the time spent on its construction. I chanced to have 18 lighter flints on hand; this determined the size of the engine that is shown full scale in my drawing [above]. The axle was an ordinary sewing needle broken near the middle. The sharp end was discarded and the broken end of the remaining part rounded and polished. The eye was then threaded with a quarter-inch of fine copper wire as a stop for a washer made of lucite which supported the disk, as shown in the lower right detail of the drawing. The rounded end of the needle is attracted to one pole of a small alnico magnet clamped in position as shown. The flints are stuck to the edge of the rotor by quick-drying cement which has been thinned with acetone.

"Energy to drive the engine is taken from an electric soldering-iron fitted with a short length of copper tubing split at the outer end. The magnet which exerts force on the flints actually consisted in my case of a pair of small alnico bars salvaged from a discarded magnetic ash tray. They were assembled with the north poles and south poles pointing the same way, and were held together with a rubber band. This assembly was placed close enough to the flints to pull the disk about five degrees out of plumb. The split portion of the hot copper tube was placed over the flints at a point as close as possible to the driving magnet. When heat was applied, the rotor turned somewhat unevenly at about a third of a revolution per minute."

Bibliography

A FIELD GUIDE TO REPTILES AND AMPHIBIANS OF THE UNITED STATES AND CANADA EAST OF THE 100TH MERIDIAN. Roger Conant. Houghton Mifflin Co., 1958.

LIVING REPTILES OF THE WORLD, Karl P. Schmidt and Robert E. Inger. Hanover House, 1957.

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