Together with the frozen remains of the woolly mammoth and woolly rhinoceros in the Far North, they have also found the bones of the reindeer (Rangifer tarandus). North America’s native reindeer is called caribou. The remains of the reindeer they have also found much further south, from where it is not living now: in southern Siberia and southern Europe. – What does that prove? - Where is the reindeer living now? How far south? Is the reindeer an arctic animal? Would the mammoth be able to graze in the Far North, just like the reindeer of today? What have scientists found out about this?
The German paleontologist R.-D. Kahlke (1994:80) reports about the reindeer (Rangifer tarandus): "During the last glacial, its range reached from N-Spain to the Far East of the Russian Federation and across Beringia and to N-America. The many places, where it was found, do show us that the cold-insensible R. tarandus has lived in the open steppe-tundra, but also in taiga-like biotopes. Mixed woods it avoided. The reindeer populated lowlands and also mountainous regions. The southern areas, mainly its European range, reached into zones of a milder climate. Into thick forests, Rangifer did not go. The (southern) border of its range, according to the fossils found now in Europe, lay roughly between 42°N and 44°N, and in Asia between 49°N and 52°N. Half-deserts and deserts here often prevented its moving further south. Only in the Primorski Krai the animals have crossed the 45th latitude."
The reindeer (Rangifer tarandus) in late autumn on the arctic tundra. Also the female reindeer has antlers, but much smaller ones. After: V. G. Heptner et al. (1966:388). In Eurasia, the reindeer is living in the Far North, on polar desert and arctic tundra; further south in the boreal forest (taiga). This deer is also found much further south in the temperate zone, on the steppe and forest-steppe of the Altai, on the Central Asian High Plateau.
Caribou, how heavy?
During the late Pleistocene, the caribou has lived in the Far North on a zonal steppe and forest-steppe, and not on arctic tundra. This reindeer has lived up there together with many other kinds of animals, adapted to the steppe and forest-steppe. In what kind of a climate has the caribou lived up there? How long has been then up there the growing-season of the plants?
Prof. R. D. Guthrie: "One would expect to find an increase in body size in reindeer (Rangifer), musk-oxen (Ovibos), and moose (Alces), when they expanded in the Holocene to dominate the northern ungulate fauna. Presumably, caribou, musk-oxen, and moose became more abundant with the rise of more moist conditions and the accompanying increase in shrubs and tundra vegetation. I found that in fact, the Alaska Pleistocene specimens of these three species did average larger in body size, than living species. (The Alaskan subspecies are the largest forms of the extant species.)
"In Alaska, summer forage for caribou, musk-oxen, and moose is profuse and nutritious – yet, their Pleistocene ancestors were even larger than those of today. How can this be? We know of no floristic sources that would have greatly increased the quality of summer forage during the Pleistocene. The only obvious route to large body size is to extend the period in which quality forage is available.
"There are two caribou metatarsals (= bones in hind foot) from Adak Islands (Aleutian Islands) which exceeded the fossil metatarsals in length. The Adak caribou were transplanted from the central Alaskan Nelchina herd, and have become enormous on this virgin range with a long maritime growing season. One adult bull was weighed at 700 lbs (320 kg), twice the weight of healthy bulls from most other populations [in Interior Alaska]. ... The ... caribou fossils used for comparison come from the Fairbanks area and were collected in conjunction with the placer gold mining early in the century. They date mainly from the late Pleistocene (late Rancholabrean)." (1984:495, 498).
Result
We have found out: Caribou on Central Alaska’s Mammoth Steppe were giants. The Alaskan late Pleistocene caribou averaged larger in body size, than its living Alaskan relatives did. They were able, to grow then so large, because the growing season of the plants has been then much longer than today. – How heavy has been the late Pleistocene caribou, living on Central Alaska’s Mammoth Steppe?
One adult caribou bull on Adak Island (Aleutian Islands) weighed 320 kg. That is twice as much as healthy bulls in central Alaska are weighing now. The late Pleistocene caribou fossils have come from the thick mantle of frozen silt, covering the gold-bearing gravel of old creek-beds. Guthrie, R. D. (1984, 1990). – In southern Newfoundland (SE Canada, pre-rut caribou bulls have reached a body weight of 340 kg (Geist, V. et al. 1988:243).
How much does Central Alaska’s caribou weigh now? What are its average and its largest body weight? How heavy has Central Alaska’s caribou been during the late Pleistocene, when grazing up there together with the woolly mammoth? What were its average, and its largest body weight?
The adult caribou bull in Central Alaska weighs now 181-272 kg and the adult caribou cow 91-136 kg. Bergerud, A. T. (1978). The average body weight of the adult caribou bull in Central Alaska is now about 226.5 kg, and his largest body weight is 272 kg. The average body weight of the adult caribou cow in Central Alaska is now about 113.5 kg. And her largest body weight is 136 kg. The Central Alaskan adult male caribou is 50.11% or 1.995 times heavier than the female.
Canada’s adult Barren Ground caribou bull has an average body weight of 106.82 kg. And his average shoulder height is 1120.55 mm. Canada’s average adult Barren Ground caribou cow weighs 74.52 kg. She has a shoulder height of 1050.9 mm, calculated from J. P. Kelsall (1968) App. V, VI. The average shoulder height of Canada’s adult Barren Ground caribou bull is 6.29% larger than that of the caribou cow. And the adult male weighs 30.24% more than the female.
The fossil material of the Central Alaskan caribou (from the Fairbanks area) averages 11.3% larger, than that of the living Central Alaskan caribou. Calculated from the molars M1, M2, and M3 (Guthrie, 1984:498, Table 1). The feet of Alaska’s late Pleistocene caribou seem to have been only as large, as those of the living caribou, even though it was weighing much more. The relatively small hooves of the caribou of the Mammoth Steppe do prove that it was adapted to the hard, dry surface of the zonal steppe and forest-steppe, and not to the boggy, humped surface of today’s arctic tundra (muskeg).
The shoulder height of the late Pleistocene caribou of Central Alaska was 11.3% larger, than that of Central Alaska’s living caribou. That is 1.7965 times larger. Its body weight was then 54.326% larger. The average body weight of the living Central Alaskan caribou bull is now 226.5 kg. Plus 54.326% (123.05 kg) = 349.55 kg. This means: The average body weight of the late Pleistocene caribou bull of Central Alaska (near Fairbanks) has been then 350 kg.
The largest body weight of Central Alaska’s living adult male caribou is now 1.198238 times larger, than his average body weight. The largest body weight of Central Alaska’s adult male caribou, grazing on the Mammoth Steppe, must have been then 419.76 kg. Rounded up: 420 kg. This means: The largest male caribou in late Pleistocene Central Alaska, when grazing there together with the woolly mammoth, the steppe bison, and the wild horse, weighed up to 420 kg. Central Alaska’s caribou cow weighs now about 113.5 kg. During the late Pleistocene, when grazing on Central Alaska’s Mammoth Steppe, she weighed about 54.326% (61.66 kg) more = 175.16 kg. That was her average body weight. Her largest body weight was then 1.19882 times larger. She was weighing then 210 kg.
The heaviest caribou bull on Adak Island (Aleutian Islands) weighed 320 kg. That is at (or near) the largest body weight of this population. Most of the other caribou on this Aleutian Islands weigh less. – On southern Newfoundland (SE Canada), the largest caribou bull reaches now a body weight of 340 kg. – In what kind of a climate is the caribou able to grow so large and to become so heavy?
Adak Island: On Adak Island (Aleutian Islands), the largest adult caribou bull weighed 320 kg. In what kind of a climate has this deer been able to grow there so large? - Adak Island lies near 51°N, 177°W. That is at the latitude of London, England, and Frankfurt on Main, West Germany. 10°C mean July temp., 8°C mean ann. air temp. No permafrost. 150 days above 5°C. 5 months long growing season of plants. 400 mm potential evapotranspiration (PE). 30 kcal cm² mean ann. net radiation at earth’s surface.
Southern Newfoundland: Southern Newfoundland, in SE Canada lies near 48°N, 51-55°W. The pre-rut caribou bull may reach there a body weight of 340 kg. 48°N lies at the latitude of Paris, France, and of Stuttgart, SW Germany. 4.7°C mean ann. air temp. No permafrost. 15°C mean July temp. 35 kcal. cm² mean ann. net radiation at earth’s surface. 150 days above 5°C. 5 months long growing season of plants. 90 days above 10°C. 450 mm PE. 1250° temperature sum with days above 10°C.
Result
In such a climate, the caribou is able to reach now a body weight of 320-340 kg. The growing season of the plants must be there 5 months long. And there is no permafrost. When the woolly mammoth was grazing in Central Alaska on zonal steppe and forest-steppe, the adult male caribou was weighing an average 350 kg. And his largest body weight was then up to 420 kg. Central Alaska must, therefore, have been then much warmer and milder, than it is now on the Aleutian Islands and on Newfoundland. There has been then no permafrost, no ice and snow, and no arctic winter. The growing season of the plants must have been then about 7-9 months long. Otherwise, this deer could not have been able to grow up there so large and to get so heavy. In an arctic climate this is not possible.
Left: The small caribou, living now in Alaska. Right: The much larger caribou living on the Mammoth Steppe during the time of the woolly mammoth. Drawing from R. D. Guthrie (1990:265). The living Alaskan caribou is only a dwarfed form of the late Pleistocene caribou. It was able to grow so large, because the growing season of the plants has been then much longer up there, than it is now (R. D. Guthrie).
Reindeer, Elephant and Rhinoceros Range
How much food does the reindeer’s pasture contain in summer and in winter? How much aboveground dry matter and digestible crude protein does in contain during the different seasons of the year? Would the mammoth and rhinoceros have found there enough to eat?
Professor Eliel Steen, Institute of Plant Husbandry, at Uppsala, Sweden, and his team, have studied the nutrition of Scandinavia’s reindeer pasture for several years. They published their findings in 1968: In August, aboveground dry matter on Scandinavia’s reindeer pasture is at its peak. It contains then an average 74.683 g DM/m², 7.866% DCP = 5.875 g DCP/m². From the beginning of December till the end of April, Scandinavia’s reindeer pasture contains only 13.164 g DM/m², 2.468% DCP and 0.325 g DCP/m² month.
The elephant and white rhinoceros do have very similar nutritional requirements. The African elephant is still able to live, where there is 300 mm of rain per year, producing 255.33 g DM/m² and 21.703 g crude protein (CP) at 8.5% CP per year. When digesting 40% of this crude protein, this fodder contains then 8.681 g DCP/m². This aboveground dry matter and crude protein is growing in Africa month by month during at least 8 wet months of the year. In Scandinavia’s reindeer pasture, the plants are growing only during about 3 months of the year.
The elephant in Tsavo East N. Park, Kenya, was starving to death during the great drought of 1970-71, when only 200 g/m² aboveground dry plant matter had grown per year. Scandinavia’s reindeer pasture, with its 74.683 g DM/m², is producing 2.68 times less, than the amount, at which elephant and black rhinoceros are starving to death with a full stomach. This alone already proves beyond any doubt that the elephant and rhino are not able to graze in the Far North, just like the reindeer of today.
Qualitative annual variation of reindeer grazing (approximate diagram) in Arctic and Subarctic Europe (northern Norway, Sweden, and Finland). From: Eliel Steen (1968:121) Fig. 2. The solid line shows us the percentage of the crude protein in the dry matter. I have assumed that the elephant were able to take in as much dry matter a day, as it needs, to maintain its body weight. Actually, this giant would not even have been able up there, to take in as much dry matter, as it needs to maintain its body weight. It would still starve to death with a full stomach, due to lack of digestible crude protein, around 12 February: after 4.5 months, counting from 1 October. This proves quantitatively that the woolly mammoth has not been able to live in an arctic climate, just like the reindeer and the caribou of today. It would have pitifully starved up there to death within a few months.
Reindeer/Caribou Maintenance
How much must Eurasia’s reindeer and North America’s native caribou eat per day, in order to maintain its body weight in winter? How much metabolizable energy (ME) and digestible crude protein (DCP) do they need per kilogram of metabolic body weight (kg 0.75) per day?
E. H. McEwan and P. E. Whitehead, Canadian Wildlife Service, University of British Columbia, Vancouver, B.C., report in the Canadian Journal of Zoology. Vol. 48, Sept. 1970 under the heading "Seasonal changes in the energy and nitrogen intake in reindeer and caribou": Digestible nitrogen required for N [nitrogen] equilibrium = 0.462 g N/kg0.75 day. 0.462 g dig. N x 6.25 = 2.8875 g DCP/kg0.75 day. The 70 kg reindeer/caribou at winter maintenance needs 5.5 Mcal ME/day. This means: At a body weight of 70 kg, the reindeer/caribou needs 227 kcal ME/kg0.75 per day, to maintain its body weight.
Robert G. White, Professor of Zoophysiology and Nutrition, University of Alaska, at Fairbanks, wrote to me on June 4, 1982: DCP maintenance for reindeer/caribou = 0.46 N x 6.25 = 2.88 g DCP/kg0.75 day.
The non-lactating elephant cow Jap, which F. G. Benedict (1936) has studied, needs 3.228 g DCP/kg0.75 day and 144 kcal ME/kg0.75 day, to maintain her body weight.
How much must the adult white rhinoceros (Ceratotherium simum) eat, to maintain its body weight? D. L. Frape and co-workers (1982) have studied two adult white rhinoceroses. They were at maintenance at 716 kJ DE/kg0.75 (= 171.052 kcal DE/kg0.75 day). At DE x 0.78 = ME, that is 129 kcal ME/kg0.75 day for maintenance of the adult white rhinoceros. From D. L. Frape’s findings (DM intake, CP content, and CP digestibility) I then found out, how much digestible crude protein the adult white rhinoceros needs per day, to maintain its body weight. It is 2.657 g DCP/kg0.75 day. That is a little less than that of the Indian elephant.
Reindeer, Elephant and Rhinoceros
Advocates of the modern ice-age theory do claim: The woolly mammoth and woolly rhinoceros have lived together with the reindeer during the Last Ice Age in a severe arctic climate. It has been then much colder, than it is now in NE Siberia. The bones of the reindeer they have found together with those of the woolly mammoth and the woolly rhinoceros. This clearly proves that they have grazed in the Far North on arctic tundra and polar desert, just like the reindeer of today. Arctic animals prove an arctic climate. – Is that true? If so, we must ask ourselves now:
How much must the woolly mammoth and the woolly rhinoceros have eaten each day? How much more digestible crude protein (DCP) and metabolizable energy (ME) did they have to take in then each day on the arctic tundra or steppe-tundra, when grazing up there, just like the reindeer of today? The elephant and rhinoceros do not chew their cud, like the reindeer does. So they are able to graze longer. How much more digestible crude protein must the 3,000-kg adult elephant then take in each day, than the 80-kg adult reindeer? How much more must the 5,000-kg adult elephant eat per day, than the 80-kg reindeer? And how much more must the 10,000-kg elephant eat per day, than the reindeer?
The 3,000-kg adult elephant has to take in as much digestible crude protein per day, as 16.9 adult reindeer, weighing 80 kg each. And the 3,000-kg adult elephant would have to take in then as much metabolizable energy, as 9.6 reindeer, weighing 80 kg each. It is rather doubtful, whether the elephant would even be able to take in as much food (DCP, ME) per day, as a single reindeer, without ruining the sparse, fragile plant-cover of the arctic tundra or steppe-tundra for years.
The 5,000-kg adult elephant would have to take in then as much digestible crude protein per day as a herd 24.8 reindeer, weighing 80 kg each. And this giant would have to eat then as much metabolizable energy per day as 14.1 reindeer.
The 10,000 kg adult elephant would have to take in per day, when grazing in the arctic tundra or steppe-tundra, as much digestible crude protein, as 41.8 reindeer, weighing 80 kg each, and as much metabolizable energy, as 23.7 reindeer.
This clearly proves to me that the woolly mammoth could not have lived in an arctic or subarctic climate, just like the reindeer of today. This giant would not have found enough to eat on the arctic tundra, steppe-tundra, or any other type of arctic plant-cover. There is too little to eat. The idea that the mammoth was adapted to a severe arctic climate, is without any scientific basis whatsoever. These new findings have now quantitatively disproved this.
Reindeer and Rhinoceros
Could Eurasia’s late Pleistocene woolly rhinoceros have lived in the arctic tundra or steppe-tundra, just like the reindeer of today? Would it have found enough to eat up there? How much must the woolly rhinoceros have eaten, than the reindeer?
The adult woolly rhinoceros usually has a shoulder height of about 1.6 m. A living rhinoceros, with a shoulder height of 1.6 m weighs now 1.1 to 1.5 tons. How much food (DCP, ME) would the woolly rhinoceros then have had to take in per day, when grazing on the arctic tundra or tundra-steppe, just like the reindeer of today?
The 1,100-kg adult rhinoceros (and woolly rhinoceros) would have to take in then as much digestible crude protein per day, as 6.5 reindeer, weighing 80 kg each. And it would have to eat then as much metabolizable energy as 4.6 reindeer.
The 1,500-kg adult white rhinoceros (and woolly rhinoceros) would have to take in then as much digestible crude protein, when grazing on the arctic tundra, as 8.3 reindeer, weighing 80 kg each. And it would have to eat then as much metabolizable energy per day, as 5.8 reindeer.
The white rhinoceros is grazing systematically, like a lawn mower. The reindeer/caribou, on the other hand, is covering each day a large part of its range, taking only a little bit at each place. It is nibbling a little bit here, and a little bit there, choosing the most nourishing parts of the edible plants. Many of the plants of the tundra are poisonous to ungulates. They cannot eat them, as Prof. R. D. Guthrie observed. Also, where there are many edible plants in the arctic tundra, the reindeer is still not able to graze there systematically, like the white rhinoceros. It is not able to graze there "like a lawn-mower". Because the plant-cover of the arctic tundra and tundra-steppe is too sparse, is too fragile. It would not be able to withstand this systematic grazing. The rhino would destroy then the fragile arctic plant-cover for years.
Thus, the white rhinoceros (and woolly mammoth) would not even be able to take in as much food per day on an arctic plant-cover, as a single adult reindeer. That is in summer. In winter, the Far North is covered with hard, drifted snow. This drifted snow is covering then the lushest spots in the lower parts. Hence, in winter it would be still worse. Thus, also the assumed adaptation of the woolly rhinoceros to a severe arctic climate is without any scientific basis. It is only science fiction.
Two large Alaskan caribou bulls in autumn during the rutting season. Drawn by Doug Lindstrand, Alaskan Sketchbook (1981:95).
Scandinavia’s Reindeer Pasture
Professor Eliel Steen, Institute of Plant Husbandry, in Uppsala, Sweden, has studied with his team of botanists for several years the plant-cover of the reindeer’s pasture during the different seasons of the year. They have worked in Europe’s arctic and subarctic zones: in Norway, Sweden, and Finland. In his report, "Some aspects of the nutrition of semi-domestic reindeer" (1968:121) Fig. 2, Professor Eliel Steen gives also the percentage of the crude protein, contained in the dry plant-matter on northern Europe’s reindeer pasture during the different months of the year (solid line). He also says: During about 250 days of the year, the vegetation is almost completely wilted.
If the vegetation on Scandinavia’s reindeer pasture "is almost completely wilted" during about 250 days of the year, we must ask ourselves: How much crude protein (dry weight) does it contain then in winter? How much does the aboveground vegetation contain from the beginning of October till the end of April? How long would the 3-ton adult elephant be able to live then on northern Europe’s reindeer pasture in winter?
We found out already: From the beginning of December till the end of April, Scandinavia’s reindeer pasture contains only 13.164 g DM/m², 2.468% DCP and 0.325 g DCP/month (dry wt) per month. How much of this crude protein is the elephant able to digest? We want to make it here as easy as possible for the poor mammoth, when grazing in winter on Scandinavia’s reindeer pasture. So I have assumed here, contrary to all the evidence, that this tusker is able to take in as much dry matter (fodder), as it needs on its normal home-range. So we do not want to look now here at the elephants energy intake, only at its intake of digestible crude protein. How long would the 3-ton adult elephant be able to live then in northern Europe in winter, while grazing there just like the reindeer? The following table will help us, to find the answer.
3,000-kg adult Elephant on Scandinavia’s Reindeer Pasture in Winter
Month: The table begins on 1 September. And it ends on 30 April.
%CP: In September, Scandinavia’s reindeer pasture still contains 8.642% crude protein (dry wt). In November it contains only 4.321% CP. And from January till April it has only 3.025% CP
%DCP: In September, the food of the elephant, grazing in winter on northern Europe’s reindeer pasture, contains 5.7% digestible crude protein (DCP). Because the elephant is able to digest then about 66.0% of this crude protein. When eating food, containing only 2.0% CP (or more), the tusker is not able to digest its food anymore. That is: the microflora in the elephant’s digestive tract will first starve to death, because the elephant’s fodder contains too many fibers and too little protein. The elephant will starve to death with a full stomach. In November, with its 4.321% CP, the elephant’s food contains 1.102% DCP (dry wt). It will digest then only 25.5% of this crude protein. From January till April, with its 3.025% crude protein (dry wt), the elephant’s food contains only 0.302% DCP. It will digest then only 10% of this crude protein.
DCPI g/day: The Indian adult elephant cow Jap needed 3.228 g DCP/kg0.75 day for maintenance. And she took in then 97.284 g dry matter (DM)/kg0.75 day. In September, when still at maintenance, the 3,000-kg adult elephant will take in then 1,308 g DCP/day. But from January till April, the giant will take in then only 119 g DCP/day. We do assume here, contrary to the evidence: The elephant is taking in here as much dry matter, as it needs for maintenance. Actually, there is also far to little dry matter in winter on Scandinavia’s reindeer pasture, to feed an elephant.
DCPI g/month: In September, when still at maintenance, the 3-ton elephant takes in then 39,255 g DCP (dry wt). But in January it takes in only 3,692 g DCP.
DCPI g/month needed: In September, the 3-ton adult elephant needs and still gets 39,255 g DCP.
DCPI deficit g/month: In October, the 3-ton adult elephant has taken in 9,622 g DCP too little, below its level of maintenance. But in January, February and March, this animal is taking in 36,871 g DCP too little, if it is able to live so long.
DCPI deficit and death: From the beginning of October onwards, the elephant’s DCP-intake-deficit is increasing all the time. Around 12 February, since the 1st of September, after about 4.5 months, the elephant’s DCP-intake-deficit has reached the deadly amount of 123,845 g DCP (dry wt). That is 4.128% of its body weight. The giant then starves to death on Scandinavia’s reindeer pasture with a full stomach, due to lack of digestible crude protein.
In this model, I have assumed that the 3-ton elephant is able to take in as much dry plant-matter, as it needs for maintenance. It needs then 97.284 g DM/kg0.75 day. Actually, it would not find enough dry matter up there in winter either. So, the tusker would have starved to death on Scandinavia’s reindeer pasture that much sooner. This clearly proves to me: Neither the extant elephant, nor the extinct woolly mammoth would be able to live in the Far North, just like the reindeer of today. The woolly mammoth and the woolly rhinoceros were not adapted to an arctic climate. They were not able to live in ice and snow, just like the reindeer of today.
A large Alaskan caribou bull during the rutting season. Drawn by Doug Lindstrand (1981:95). In late Pleistocene Alaska, when the mammoth was grazing up there, the caribou has been much larger and heavier, than it is now. This is proved by its skeletal remains. The Alaskan caribou was able, to grow then so large, because the growing season of the plants has been then much longer, than it is now (R. D. Guthrie, 1984, 1990).
Bergmann’s Rule
Someone might object now and say: The mountain sheep, caribou and muskox of late Pleistocene Yukon/Alaska have been much larger and heavier, than those living up there today, because it has been then much colder in the Far North than now, not warmer! The further north the mammal is living, and the colder it is, the larger and heavier it will become. This has been proved now scientifically by Bergmann’s rule. This is a serious objection. Is it valid? Is Bergmann’s rule true? Has it been proved scientifically?
Valerius Geist, Professor of Biology at The University of Calgary, Alberta, Western Canada, has re-examined Bergmann’s rule critically. He reports about his findings under the heading "Bergmann’s rule is invalid", in the Canadian Journal of Zoology (1987:1035): "Bergmann’s rule, claiming that in homeotherms [warm-blooded animals] body size increases inversely with temperature so that, intraspecifically, body size increases latitudinally, is not valid, nor is the explanation of this rule. In large mammals body size at first increases with latitude, but then reverses between 53 and 65°N, so that small body sizes occur at the lower and higher latitudes. This is predicted by the hypothesis that body size follows the duration of the annual productivity pulse, so that body size is a function of availability of nutrients and energy during periods of growth. Correlations between body size and temperature are shown to be spurious. If reduction in relative surface area is indeed an adaptation to conserve heat, then mammals should increase in size from south to north at rates two orders of magnitude greater than they do. Bergmann’s rule has no basis in fact or theory."
"I shall add my voice on the side of dissent, and hope to show that Bergmann’s rule is not fact but fiction, as are of necessity all explanations of this rule. The classic explanation advanced by Bergmann, and widely accepted, is that large size is adaptive in cold environments, because the surface area decreases to mass as the 2/3 power of mass. Consequently, large mammals lose less heat relative to mass, and large size in cold environments is an adaptation for energy conservation. The classic explanation allows precise quantitative predictions that can be tested. These tests showed Bergmann’s rule to be untenable. The trend towards greater size reverses between 60 and 65°N parallel; for mountain sheep the reversal occurs at lower latitudes, between 48 and 53°N where the largest sheep are found (Cowan 1940). These figures support McNab’s (1971) conclusion that the statement that body size is inversely related to temperature is not tenable.
"Above 60-65°N various terrestrial large mammals grow smaller in size with latitude, including Rangifer, Ovis dalli, O. nivicola, Ovibos, Ursus arctos, Alopex lagopus, and Canis lupus... What positive correlations between body size and latitude there are appear spurious. They are a consequence of the fact that most species of large mammals live south of the 60th parallel N. Thus the reason why elk (Cervus elaphus canadensis), white-tailed deer (Odocoileus virginianus) and black-tailed deer (Odocoileus hemionus) comply with Bergmann’s rule is because they fail to extend beyond 62°N. The reason why musk oxen, Dall’s sheep, snow sheep, caribou, or grizzlies are ‘exceptions’ to the rule is because they do extend beyond 60°N.
"The hypothesis that body size follows the duration of the annual productivity pulse appears to be valid, and has a sound rationale: body size appears to be a function of how much time growing individuals have unhindered access to food of the highest quality. This predicts that ungulates that follow the productivity pulse altitudinally should be directly proportional in size to the range of altitude they cover during the vegetation season, as Shackleton (1973) suggested for mountain sheep.
"Figure 3 shows, for instance, that a 12.5-kg hairless beast can survive at 20°C (mean January temp., Managua, 12°N); at a temperature of 0°C (El Paso, Texas, 32°N), the beast would have to weigh 450 kg to survive; at –17°C (Calgary, Canada, 51°N) it would have to weigh 3200 kg; at –32°C (Yellowknife, Canada, 62°N), it would have to weigh 15 000 kg. A decrease in temperature of 20°C would necessitate a 36-fold increase in body mass; a decrease of 52°C would necessitate a 1200-fold increase in size.
"White-tailed deer change about 4-fold in mass from Central America (12°N) to Canada (61°N); wolves increase less than 2-fold in mass from Mexico to Alaska. Empirical facts and predictions from Bergmann’s rule fail to match by orders of magnitude. The small increase in size with latitude occasionally observable are, clearly, no evidence in favour of Bergmann’s rule." - Geist, V. (1987:1037).
"That the classic explanation of Bergmann’s rule turns afoul of the difference between relative and absolute values, as emphasized by McNab (1971), can be illustrated by the following example. Relative surface area decreases from 0.05 m²/kg in a 12.5-kg beast, to 0.1 m²/kg in a 450-kg beast. The subsequent 5-fold ‘saving’ in relative heat loss is bought at a 36-fold increase in absolute mass, or a 14.5-fold increase in metabolic cost.
"A hair coat of only 1 cm thickness, with an insulation value of 0.68°C.m².Mcal.24 h.mm would raise insulation to 21.9°C and would drop T[emperature] for the 12.0-kg beast to 12°C. That T without 1 cm of hair coat, is reached at about 65 kg body mass, or a 3.4-fold saving in metabolic coast. The same result is also reached by making the hairless 12.5-kg beast ‘rounder’ by 0.5 units.
"A hair coat 2.5 cm thick would allow the 12.5-kg beast to exist at 0°C. Hair is thus infinitely superior to either an increase in size or roundness as an adaptation to cold, making biometrical climes irrelevant to interpreting the thermal adjustment of animals (Scholander 1955, 1956; Irving 1957, 1972). As Scholander (1956) noted, the physiological interpretation of ecogeographical rules has been treated much too lightly by proponents of this rule. I conclude that there is neither an empirical nor a theoretical basis for Bergmann’s rule." - Geist, V. (1987:1037).