THE HIGHEST LIFE

LAWRENCE W SWAN¹

MY INTENT IN writing this account about life in the highest areas of the world is to acquaint mountaineers with some knowledge about the living things that may be encountered at extreme altitudes and the observations that may be made to help elucidate the reasons for their presence in what may sometimes appear to be impossible environments. Life, if only in the form of some interesting bacteria, extends to the summit of Everest and the observant climber can add much to the present information concerning distribution,temperatures,behavior or merely the existence of animals and plants among the high peaks.

During the American Expedition to Makalu in 1954 while exploring the high, nearly snowless slopes up to and above 6100 m to the northwest of the peak, I rediscovered the curious Salticid spiders thart R.W.G. Kingston had found at 6706 m on Everest during the 1924 expedition. These small jumping spiders (Euophrys omnisuperstes) could be found in areas where there was no evidence of plant life and, since spiders are universally predaceous, their only food could have been the springtails (Collembola) that hid under the rocks and the occasional flies (Anthomyidae) whose pupae were also found beneath rocks. It is a general assumption of biology that animals are dependent upon the food produced by plants and, therefore, in the absence of plants, the survival of such creatures among the unproductive rocks elicited an enigma. In searching further, it became apparent that in small cavities, especially cilong the base of rocks, there were minute accumulations of windblown organic materials, such as pollen, tiny pieces of plants, seed plumes, fragments of insects and so forth. This debris was slowly attacked by fungi and both the springtails and the anthomyid flies survive on fungi and the animals were only present where the windblown aggregations existed. This observation prompted an explanation for the existence of finimals beyond the realm of photosynthetic plants and so I have proposed <i new zone of life, a new biome type that extends beyond the Alpine Region, the Aeolian Region (after Aeolus, the Greek god of the wind) where life is supplied by air-borne nutrients.

 

An elaboration of this new zone divides it into three phases, namely (1) a terrestrial division represented, for example, by the spiders and their associated prey and (2) a nival phase where wind-blown, snow-trapped insects are eaten by birds, other insects and those remarkable phalangids, sometimes called 'daddy-long-legs', that use their eight legs as stilts above the cold snow to reach down and eat their prey. There are also the nival snow algae and their associated bacteria that in turn support a variety of microscopic organisms such as protozoa and rotifers. Finally, (3) there is an aquatic phase exemplified by such crustaceans as the fairy shrimps (Branchinecta orientalis) and midge larvae (Chirbnomus, Diamesa, etc,) that live iaglacial pools. There are also the abundant insect larvae found where glacier torrents emerge from under the ice which, in turn, attract birds such as redstarts and since these may nest right alongside their food source, they also become aeolian in their ecology. The aquatic creatures survive on nutrients that have accumulated from air-borne sources and have been preserved in snowfields over the millenia to be released into the melt-water.

It is not usually appreciated that organic materials, derived initially from plants, are very nearly ubiquitous and in addition to the miscellaneous debris mentioned above there is an as yet unqualified supply of proteinaceous material derived from ocean spray that is carried in the atmosphere and falls to earth with snow. Snowfields as they melt or sublimate into vapor carry their small loads of nutrition (by adsorption to remaining particles of ice) as they diminish in size so that the remnant snow-patch may contain considerable concentrations of food. When this finally melts, the ground surface acquires this accumulation to the benefit of a local group of terrestrial organisms (or to their presumed disadvantage if the snowfield acquired radioactive materials from the atmosphere or acidic particles that fall out from industrial pollutants which, likewise, became concentrated).

Based on the premise that organic materials are nearly universal and, therefore, food for some life is available anywhere on earth, 1 supplied climbers of the 1963 American Everest expedition with sterile vials with which they could scoop up granular soil from near the summit. If there were to be any microbes in these collections, I assumed that there must be some liquid water available and that temperatures above freezing must occasionally occur. Since a few icicles had been photographed near the summit, I assumed that water could be available and since I had myself recorded high temperatures on the surface of rocks in the sun at very high altitudes, the prospect of success seemed clear. Whereas, highly motivated, single purpose climbers are not noted for thier cooperation in scientific adventures, two climbers, Lute Jerstad on the West Ridge and Barry Corbet on the South Col approach amazingly filled their vials at 8400 m (my friend, the late Willi Unsoeld had one of my vials in his pocket when he and three others spent that awful night out on the slope at 8500 m and where he and Barry Bishop lost their toes).

When the vials were returned to me, I realized that they also contained air at nearly one third the pressure at sea level so that their opening might let in contaminant bacteria. I arranged for the laboratory at Ames Research Laboratory, Mountain Viewv California, then deep into research on Martian environments, to perform a 'dry run' on my samples as if they were the first specimens from outer space. Indeed, the summit area of Everest is not only physically closest to outer space, it resembles an exobiological site more closely than any other place on earth in terms of radiation, solar intensity, low atmospheric pressure and the range of diurnal - nocturnal swings in temperature (I sometimes, in jest, chide astronauts whose encapsuled environment is near sea level that I have experienced outer space more than they have). The results, in a few days, were phenomenal and where psychrophilic forms of bacteria (those that prefer lower temperatures) might have been expected, the most growth occurred on agar plates kept at higher temperatures. This was a surprise to the microbiologists but I was prepared to believe that some ground surface temperatures above 8000 m may warm up considerably. All the many species of bacteria evidenced pigments indicating their exposure to high solar intensities and they all showed adaptations to freezing and thawing each day. These characteristics removed them from the possibility that they were derived from casual wind-blown spores and that, in fact, they existed as metabolizing organisms on this summit of earth.

To further emphasize their unique attributes, Edward Ishiguru, a graduate student at San Francisco State University, isolated one form of bacteria that defied identification. Its life cycle was so unusual that he suggested a separate family to house it. Some years later, another microbiologist found something similar in the arid regions of the Western United States which he named Geodermatophilus obscurus (suggesting something obscure that looked like a common skin bacteria but which comes from the ground). Not knowing what to do with the Everest form, it was lumped into this species and still remains in a sort of limbo as Geodermatophilus obscurus everestil. If there could be any wind-blown organic nutrients on Mars, this or a similar organism, would be the best candidate for survival on that planet and could thus extend the Aeolian Region beyond the earth. It would seem that, in select micorhabitats, the availability of water and temperatures above freezing on Mars may resemble the summit of Everest.

The bacteria and presumably some yeasts and fungi represent the highest forms of resident life on earth. The salticid spiders at 6700 m come next among the known organisms but I might expect that some springtails and debris mites could be found higher than this. It is here that I believe climbers can make some discoveries for even some casual turning over of smaller rocks may reveal these small insects and arachnids. One has to look closely. They can be collected into alcohol by touching them with a wet probe of some sort. A tweezers dipped into a vial of preservative will make them stick on. They do not need to be grasped.

Another significant contribution that can be made by climbers is the discovery of more of those strange, primitive insects that are sometimes referred to as 'glacier fleas', the jumping bristletails. These are creatures (related to the common silverfish that may be a pest in houses) belonging to the Family Machilidae of the Order Thysanura. They are able to leap when they twist their abdomens beneath them and then straighten out to trigger themselves in a jump of several feet. They hop around on the glacier rocks and sometimes fall into a crevasse. I do not know if they ever get out. The species I found (Machilanus swani) that extended up to 5800 m on the Barun glacier near Makalu could live on the bare rubble that covered the ice surviving on windblown detritus. I can think of no environment so supremely hostile where the land moves and rocks tumble in a world of ice and crevasses and unpredictability. These creatures are relatively common and yet my specimens were the first to be received by any museum from a Himalayan glacier. I would dearly like to see them collected across the whole Himalaya for I feel sure that various glacier systems may carry different species. They could be clues as to how the glaciers of the past were linked or associated. All that is required is a noticing eye and some willingness to wander over precarious terrain. As for all such specimens, a small vial of preservative alcohol will do. Even vodka will work in an emergency.

I should note here that various strong-flying insects may fly up the slopes to the- limits of plant life and beyond. Butterflies such as the tortoise shell and bumble bees are most easily identified. But these wanderers are not residents. Their dead bodies may, however, add to the aeolian supply of nutrients. There is also the curious phenomenon of 'hill-topping' where insects, commonly butterflies, ascend a slope and when it ceases at the summit, proceed to fly around in circles above the top. Such creatures are presumably trapped by the-configuration of a fairly pointed hill or eminence. Other insects that may have a wide and scattered distribution apparently use prominences as locations for finding the opposite sex. They seem to fly upward until the slope ends and, if others of the species are doing the same, they meet at the summit. The larger flies are particularly apt to behave in this way and collections made in such a location might reveal interesting sex ratios.

The highest vascular plant I collected was a prostrate pink (Stellaria decumbens) at 6130 m on the divide between the Barun glacier and Tibet. Delimiting the highest vascular plant is difficult to do for climbers may casually mention that they saw a flower or even suggest a species that they observed along the way. An altitude must be verified and a specimen obtained and identified by an appropriate botanist. It should become a museum specimen. In 1921, during the first reconnaissance of Everest, A.F.R. Wollaston collected a prostrate plant, Arenaria musciformis at 6120 m. Recent collections by Chinese botanists on the north slope of the mountain have not matched this altitude.

It should be noted that vascular plants (not mosses or lichens) appear to reach the highest altitudes and, in my experience, exceed the altitude limits of lichens and mosses. This is quite contrary to what happens in more temperate mountains and in polar regions. It would seem that extreme altitudes also witness extreme dessication where snow rapidly sublimates (the solid evaporates qjirectly into a gas avoiding the liquid phase) except for a portion of melting that escapes beneath rocks or into the ground. Here, the roots of plants may reach the liquid while lichens and mosses, without roots, must bear the dryness out on the exposed surfaces of rocks. Hence, the highest lichens I have seen are at around 5900 m and mosses somewhat lower. Some of the highest lichens are foliose forms that actually live on the surfaces of prostrate flowering plants where these eke out an existence on some moister spot and the lichens usurp some of this moisture. It is quite apparent that in areas recently exposed by a retreating snowfield or glacier that it is the plant with a soil-reaching root system that is the first pioneer into the area.

My previous definition of the Aeolian Region did not include green plants but clearly the algae of snow are aeolian and it seems quite certain that lichens and mosses near their upper limits are also aeolian for they usually exist quite separate from the scattered vascular plants that produce their own food from carbon dioxide and water with nitrates and minerals from the soil. Lichens, in particular, absorb nutrients from the air in molecular form and such materials dissolved in rain or snow. They do not usually etch the rock or erode its surface. The bluegreen algae, the cyanophytes, are a problematic case for these organisms are able to fix atmospheric, molecular nitrogen and can thus produce their own protein from carbon dioxide and water. Just how they are dependent upon atmospheric nutrients or minerals isn't quite clear but (as it appears so common in polar research) to have them be the primary source of soil nitrates seems to ignore aeolian origins. It would seem that green algae that actually grow beneath the surfaces of porous rocks in the Antarctic must have some contribution of nitrate from the atmosphere. I should restate the definition of the Aeolian Region as a life zone that commences where a major contribution to the existence of an animal or plant is made by air-borne nutrients. Minor contributions of nutrients may be common at lower altitudes (tropical bromeliads such the so-called Spanish Moss that may grow on telephone wires are notorious 'air-feeders') so that the commencement of the Aeolian Region is largely one of the degree of dependency. Thus, some glacier-fed pools and even snow-fed tarns at altitudes near 4500 m and well below the permanent snow line in the Eastern Himalaya can be considered aeolian.

The Alpine Region can be characterized as commencing at tree line and extending to the limit of vascular plants. In the Eastern Himalaya this extends from 4100 m to 6100 m and in the Karakoram, from 3100 m to 5900 m. These are enormous ranges and reflect the depth and size of the mountains and how at high altitudes, especially beyond the southern, more snow-covered slopes, the growing season may be long and insolation enhanced. Consider that on Orizaba in Mexico, a tropical-type of isolated peak, the alpine region is aborted to extend from 4100 m to a mere 4660 m because snow may fall at almost any time of the year and there is no prolonged growing season. This sort of Alpine Region characterizes the more isolated, largely volcanic peaks of the Andes, East Africa and Indonesia. Furthermore, at the high altitudes of the Himalaya, there is a curious pseudo-maritime effect that makes the high peaks less cold in winter so that the seasonal differences between summer and winter are less severe. It would appear that, whereas the tropical peaks have no clear seasons and the year is like one long winter, the Himalaya approach the opposite and have an extended summer. I have recorded the flowering of Allardia glabra from the beginning of May until the middle of October, some 168 days between 5400 m and 5500 m. Flowering among high alpine plants in the Rockies or the Alps is long if it can reach 60 days. It is obvious that the Himalayan alpine flora reflects this extended seasonal duration and altitudinal range and with climatic varieties between very wet on the monsoon supplied southern slopes to very dry on the Tibetan exposure, the total species list exceeds any other alpine enumeration of plants.

Resident birds and mammals of the high Himalaya are primarily restricted to regions where vascular plants can be found. The highest nesting site I have discovered was at near 5700 m where a Tibetan snowcock (Tetraogallus tibetanus) had left its eggs. An early Everest expedition reported that a* presumed nest of the red-billed chough (Pyrrhocorax graculus) was made at around 6400 m near a camp where the birds were scavengers on the climbers' supplies and presumably relied on this largesse to attempt a home. The climbers left before any young were seen and one must place this record in a problematic category. Hatching eggs at this altitude is not so much a problem of supplying the embryos with oxygen as a problem of dessication inside the egg because water vapor loss at high altitudes through the egg shell and the drying of its contents limits the incubation time. Hence, nests are more successful if evaporation is decreased in some way (better enclosure of the eggs or moistened nest material or alteration of the pore structure of the egg shell) or if incubation is shortened. It would appear that this rapid water loss is the primary factor in limiting the altitude of reproduction in birds.

Mammals are more dependent upon local plants and so one might expect that the highest resident mammals are limited by the highest vascular plants at around 6100 m. It seems that the small pika (Ochotona ladacensis) recorded at 5950 m remains as the highest resident mammal. Wandering or migratory birds and mammals do much better than this. I have heard bar-headed geese (Anser indicus) fly directly over the summit of Makalu at what must have been near 9000 m and these birds have been noted elsewhere in the Himalaya flying over the highest peaks. My report on their unusual tendency to span the highest Himalaya in one spectacular flight has prompted physiologists to study this animal and they have found that it carries a unique haemoglobin that can associate with very low oxygen tensions and that its lungs are modified for thin air and that the cells of its flight muscles carry extra quantities of mitochondria, the units that function in cellular respiration (in experimental altitude chambers, the geese remain conscious and remain standing at the unbelievable simulated altitude of 12,190 m). Furthermore, the Himalayan flight of these birds reflects a time when the Himalaya were lower and the environmental conditions in Tibet were less austere. It seems that the amazing transit of these birds that conquer the Himalaya twice in every year is a sort of fossil behavior that is older than the peaks beneath them. Indeed, during the last two million years when the Himalaya made its final and most dramatic thrusts, the geese must have flown higher and "higher and higher until they now approach the stratosphere.

Wandering mammals (excluding mankind, for are not climbers merely wandering mammals ?) set a record at 6565 m that dates back to Col Howard-Bury s notations of footprints in the snow on the Lakhpa la during the 1921 reconnaissance of Everest. This has become a famous record for from it has emerged the modern legend of the abominable snowman, the Yeti of the Sherpas. One does not often read about the biologist Wollaston's remarks in the appendices of the great book (Mount Everest: The Reconnaissance, 1921 by C. K. Howard-Bury) that emerged from that daring expedition for Wollaston quite clearly suggests that the footprints were made by a wolf. In the face of much derision I have shown that the tracks are caused by the spreading of the impression by sublimation of the snow at high altitudes where one side of the indentation (the pug marks of a fox or wolf), the sun-exposed side, acquires flutings (miniatures of what one sees on the sublimating snow on the peaks). Some of these flutings resemble toe marks that face away from the sun and are generally oriented toward the north.

So much has been written about a strange creature causing these tracks, with gross imagination and even fakery filling the more impressionable varieties of literature, that I beg some consideration for that wolf (Lupus chanko) that remains, in my analysis, as the highest wandering mammal in the world. Some,respect and awe should be offered to that animal. What was it doing at that enormous altitude ? Cannot we appreciate the feats of the natural ? Must our imaginations demand the occult for our interest and wonder ? After nearly 70 years I still await a piece of genuine hair, a skat, a nest or any tangible remains of one of these legendary things. I do not demand a big hairy thing in a box but I would like something more than an impression in snow or mud where no part of the animal, no molecule of reality remains. And why have no Tom Sawyer types of young Yetis fallen off cliffs or wandered into villages to be captured ? I love the legend dearly and I hope the Yeti can always hide beyond the last snow ranges, beyond human intrusions, for I think he is better as a wisp of hope than something real that, like the mountain gorillas (veritable forest Yetis whose droppings I have witnessed at 4000 m on the summit of Muhavura among the Virunga Volcanoes in Central Africa), will be exterminated by the encroaching demands of mankind.

Reptiles and amphibians, so-called 'cold-blooded' creatures, are not usually associated with altitude and cold and yet, in the Himalaya they reach impressive heights. Consider the small skink, Leiolopisma ladacensis, collected at Khajeng Chola in Western Nepal at 5500 m and the viper, Agkistrodon himalayanus, that was found at the mouth of a glacier in Garhwal at 4900 m. One may wonder if these were not some wandering individuals far from their normal habitats but, from my experiences in Mexico, they may very well have aeolian associations. On Orizaba the nominal permanent snow line and the plant line is at 4660 m and here I have obtained a rattlesnake and a salamander. The former searches out mice and lizards and these creatures survive on the quantities of windblown insects that are blown up the peak from the tropics of Vera Cruz. The lizards (Sceloporus microlepidotus) are found among rocks that protrude from the snow above the nominal snow line at 4820 m (I sometimes refer to them as my abominable snow lizards), when it is clear they can bask in the sun and feed on the insect debris. In other words, it is not the cold, per se, but rather the availability of food and enough sunshine. I can believe that a similar association exists for these Himalayan record species.

Among amphibia the frogs are most notable since there is only one salamander (Tylototriton verrucosa) that reaches out of West China into the Eastern Himalaya at a very modest altitude of around 1800 to 2500 m. The Himalayan and Tibetan frogs of the Family Pelobatidae include Scutiger sikkimensis that is found in scattered localities along the Himalaya between 2800 and 4000 m and Scutiger alticola which is primarily Tibetan and has been collected up to 5200 m.

These frogs, together with related West Chinese species, constitute a complex of amphibians that have apparently survived the uplift of the Tibetan plateau and the later uplift of the Himalaya. Presumably they were once widespread over a* much more fluvial and hospitable land and are now left in isolated pockets with the Tibetan species virtually confined to aquatic habitats. (Much the same thing happened to snakes which were all eliminated from the high plateau except for the water snake, Thermophis baileyi, that only survives near warm springs at around 4000 m).

In 1980 I was privileged to accompany the first international tour across Tibet as a guest of the Chinese Academy of Sciences where I was able to see and collect in places where the fabled explorers of the last century made their remarkable observations. On a pass (Gyaco la, northeast of Tingri) I noticed some snow-fed ponds and was drawn to them hoping for specimens of Scutiger alticola but the black mud I scooped up finally revealed two small scaleless loaches (Nemachilinae). This was at 5200 m and somewhat higher than similar fish obtained by G. E. Hutchinson in Ladakh back in 1932 and so they represented the highest fish in the world. Their location in a pond of about one quarter of an acre in extent without any obvious stream exit made me wonder how the fish got there. Such enigmas are often blamed on birds that might bring eggs stuck to their feet or some past arrangement where the fish could swim to such an isolated locality. But the recency of the Tibetan uplift lets me reach far out for another possibility, perhaps the fish have been raised up with the land ! Not far from this site4 also at 5200 m, are the fossils of rhinocerous and giraffe that tell of a time only 4 million years ago when this bleak plateau was a warm savanna.

As I began, I shall end with an urge to promote more collecting and observing by Himalayan mountaineers and suggest some effort to coordinate the scattered information acquired by climbers. Discoveries should not remain as persona! tales or anecdotes and specimens should not be lost on shelves. There are museums where active, interested and capable biologists would cooperate. I have donated specimens to the British museum and to institutions in India but the bulk of my collections are held by the California Academy of Sciences, Golden Gate Park, San Francisco, California where they are available for examination by appropriate scientists. From such a central museum, specimens are sent out around the world to particular specialists in the groups of plants or animals involved and, ultimately, descriptions are published in journals. The Himalaya, vast and full of fascination, has an infinite supply of untrodden paths in the study of life as it does in new routes to the peaks.

A description of flora, fauna and other life at high altitudes and the possible reasons for their survival.

 

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