Wednesday, December 5, 2007

Miracle in Old Mutare

A Request for Your Thoughts

As most of you folks know, I’m trying to head up a small team that will produce a book that will illustrate the natural wonders of the Africa University campus. Because of my own training, I will focus largely on vertebrate wildlife, and in a previous essay I explained some of the difficulties in photographing local mammals these days. As I have also suggested, we’ll probably include lots of frog pictures. Thus far we’ve photographed 20 species; some of them are quite beautiful, and others are plenty cute to attract at lease a few admirers. We are also approaching 20 species on our reptile-list. Most of these will be lizards (though we have one turtle-species in the photo-files, and we hope to add another), but, thank goodness, we also have a few snakes. In my previous work here I’ve had some dealings with pythons, including one that was the largest snake I’ve ever seen. This python made quite an impression on me, and I really wanted to write (for the eventual book) a short essay telling how I felt when I saw that animal. Such narration is not my usual style, and I’m worried that it will sound exceedingly hokey (cheesy? stupid? I don’t really know the right word) in a book that’s supposed to be more or less factual. So I thought I’d float a draft of my python-essay with you folks. And I’d love to have your comments, at some point.

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Back in 1898, when Bishop Joseph Hartzell received his land-grant for “Old Umtali,” he could readily appreciate the scenic beauty and agricultural potential of the area. Still, the churchman from Ohio[1] might not have initially realized the full extent of his good fortune. He might not have known that his lands were—and would remain—blessed with an abundance of pythons.

In order to live long and prosper, African pythons must have three things: water, shelter, and an abundance of food. These requirements, of course, apply to wildlife in general, but Python natalensis—with slight poetic license, the Latin could be translated as “Christmas python”[2]—needs such resources scaled for a hatchling that could fit into your pocket and for an adult that could weigh more than you do. Around Africa University creeks, pans, and irrigation canals can supply water for most of the year, and the Mutare River never runs completely dry. Crevasses, caves, and abandoned mineshafts can serve as hideaways, but termiteria (whose entrances vary more in size than do the diameters of pythons) are most commonly used for shelter. A termite, or “white ant,” mound is icebergian in extent: its visible proportion scarcely hints at what is hidden below the surface. In this underground world, channels and chambers—any of which may be enlarged by sundry vertebrate inhabitants—provide refuges whose temperature and humidity remain constantly within python-acceptable limits. And when the clay surface of a mound bakes hard into laterite, these refuges become almost impregnable.

An African python will sometimes forage actively for its food, but more often it will strike from ambush. Perhaps because it can detect potential prey by an animal’s heat-signature against a cooler background, P. natalensis eats almost exclusively warm-blooded vertebrates. During their hatchling-year, A.U.’s pythons probably subsist largely on mice, which abound in both density and species-variety. Maturing youngsters convert to rats, plus some rabbits and a few birds. Over the years we have examined the scat left by adult pythons: identifiable remains have included a few claws from small mammalian carnivores and many horns and hoofs from campus antelopes.

The maturation-rate of wild P. natalensis is not known. In captivity, kept warm and fed all it will eat, a healthy specimen can exceed 2.5m in length within the hatchling year. In the wild this does not happen, for Zimbabwe’s winters are quite chilly, and depredation from ambush is in large part a matter of luck: some days you get the vlei-rat; most days you do not. African pythons are well-adapted for the feast-or-famine existence of an ambush predator. They are capable of very long fasts (for big adults, probably exceeding a year in the most extreme cases), lowering their metabolic rate to bare-existence levels. Then, when prey comes along, a python will take it—and, within some limits, the bigger the better.[3]


In other words, pythons hardly ever starve, so, although maturation can be quite slow, some pythons hang on, avoid the hazards of life for a few years, and eventually reach sexual maturity. Courtship and mating is well known for captive pythons, but these activities are seldom observed in the wild. Probably a patrolling male detects the special scent from the cloacal glands of a female;[4] he then follows her trail until he finds her, and mating occurs. Within about sixty days (???) after mating, the female will lay a whole bunch of eggs (perhaps as many as a hundred for a really big, well-fed momma). Most snakes abandon their eggs (or live-born young) immediately, but pythons are different. The female seeks a secluded spot (termite mound, mineshaft, whatever), lays her eggs, and coils her body around them. Then she initiates a series of contractions reminiscent of shivering in mammals. The metabolic heat produced by this intense muscular activity generates a great deal of heat, and, regardless of the ambient temperature, the eggs are maintained at about 30oC for the protracted incubation period (about 120 days). After the young do hatch,[5] the mother (apparently) loses all interest. And that is understandable; after all, she has endured a whole lot of very hard work throughout a very long fast, and she needs to go about the business of rebuilding her own resources (small antelope beware!).

We have some familiarity with pythons on the A.U. campus. In 2007 we have caught two pythons. The first was a 2m youngster in found in a molerat colony. As you can see from our photographs, this python was not at the peak of the species’ beauty. The cloudy eyes indicate that the animal is preparing to shed its skin, and the engorged ticks on its sides suggest that this snake had been spending a fair amount of time in mammal burrows. The second 2007 python was a freshly-shed sub-adult that we discovered one night about 50m behind our house.


Back in 2000 we had found another python—a bit smaller—and implanted a radio transmitter into the animal’s pleuroperitoneal cavity. This enabled us to keep up with the whereabouts of the snake for almost 100 days. Although our radio-python spent a considerable amount of time underground, in termite nests, it was also a real mover, sometimes covering over a kilometer in a single day. We were interested to note that the python used every major on-campus habitat-type (and it once ventured off campus, by about 10 meters), sometimes ambushing in a flooded lowland field, sometimes hunting in the mountain rocks. Movement between these areas required that the snake traverse a broad agricultural landscape; inevitably it made these crossings by crawling along a narrow, overgrown fence-line.

When I (Ab Abercrombie) talked proudly about my radio-python, folks around Old Mutare would always ask about its size, and they would disparage the entire telemetry enterprise when they learned that the animal was little longer than the height of a tall man. “Wait until you see the big one,” they would say; “it’s six meters long—a real python.” Somewhat sensitive about the dimensions of my favorite python, I would reply with equal scorn, “There’s no six-meter python around here. That’s almost record size, and nothing that big could survive in the agricultural heartland of Old Mutare.”

Then, in December of 2000, at the advent of the summer rains, I had trekked to the southeastern edge of campus to examine a mineshaft where I had previously photographed a pair of porcupines. The porkeys were not at home, and it was with some disappointment that I descended the mountain slope to ford the Mutare River (there being no log-bridge at the time). I had entered a dense thicket in the narrow flood-plain of the Mutare and was forcing my way through the Fragmites stems, which were almost twice my height, when my eye caught a flash of sunlight on silver-gray scales. And there it was, stretched full-length by the riverside, the Python of pythons. There is no way I can describe this enormous snake; that would be like explaining what love is, when it happens, or like describing the Seraphim. For any person of the modern world, words would degenerate into silliness: “With twain he covered his face, and with twain he covered his feet, and with twain he did fly.” As a scientist, I wish I could have laid a tape-measure along the snake; as a wildlifer, I wish I could have implanted a transmitter. And by gosh I’d have done those things if I possibly could have. But this was not a snake measurable in centimeters or locatable by radio-pulses. It was a snake outside of size and place; it was a snake belonging to the deep nature of Life itself…. Heck, I told you that words degenerate into silliness. Here is the simple truth. That snake was the best single thing that has ever happened to me, and I shall never want anything better. This was the real Python natalensis, the Christmas Python. (And if I could whisper something to you, I’d tell you how big I really think it was.)



[1] I write “Ohio” because that’s the state of residence that most mini-biographies quote for Hartzell. Actually, the man was born in Illinois and served his first church in that state. He was later appointed pastor to a church in New Orleans—to the only Methodist congregation in that city that chose affiliation with the Northern church after the denomination’s split. The 1896 General Conference of the Methodist Episcopal Church, North, designated Hartzell as Missionary Bishop for Africa. Title to the land was granted by the British South Africa Company (whose big chief was Cecil Rhodes his own self). The BSAC had been granted the land by Chief Tendai of Manyika Land, in exchange for guns and “educational opportunities.” I don’t know whose land the chief gave away—or by what right. Anyhow, when I write the actual A.U. campus book, most of this historical stuff will appear in a separate chapter. But, for now, what are footnotes for?

[2] Nowadays the big pythons of southern Africa are considered to be a species separate from their big cousins to the north (Python sebae). The Latin name for the southern species is taken from the South African province currently known as Kwa-Zulu Natal. Natal (literally, “birth”) is the Portuguese word for Christmas.

[3] Except for the termite-eating scolecophidians, considered elsewhere, almost all snakes are adapted for taking large prey. Anatomically, the issue is, “how do you get big-diameter foodstuff into a small-diameter tube, when that tube has no equipment for slicing the foodstuff into pieces of convenient size?” In my herpetology course I talk at great (excessive?) length about swallowing-adaptations, which include stretchable skin, articulations of the quadrate bones, semi-independent lower jaws, and a flexible braincase. For now, let me say that, even among snakes, big pythons are real champions at swallowing really enormous stuff!

[4] Also in my herpetology course, I define snakes as creatures that live in a world of chemical information (loosely “smells”). In almost all snakes, special glands around the cloaca (the vent, where eliminatory and reproductive functions take place) produce substances with odors recognizable by other snakes. These are typically of high molecular weight and can therefore persist at detectable concentrations for a long time on the substrate where they have been deposited. Such chemical information is not apprehended by “smell” in the strict sense (sniffing through the nostrils that excites neural pathways interpreted by olfactory centers of the brain). Instead, the chemical messages from a snake’s cloacal glands are picked up on the tips of a snake’s tongue, with which the animal explores its environment. The tongue is withdrawn into the mouth, and its tips are inserted into a pair of openings in the roof of the mouth (the entrance to the vomero-nasal organ), from which the chemical information is relayed to the brain.

[5] In most python populations this occurs near the beginning of the summer rains, when food and thermal resources for the hatchlings are most readily available.