In what kind of a climate has the woolly mammoth lived in Alaska and the Yukon Territory? Has the ground up there been then permanently frozen? Or has there been up there then no permafrost? What do the animals show us, which have lived in the Yukon Territory and Alaska together with the woolly mammoth? The steppe-ferret has lived then in the Yukon and Alaska together with the woolly mammoth, the lion and the badger. How far north have they found the remains of the steppe-ferret up there? In what kind of a climate and on what kind of a plant-cover has it lived? Where is the steppe-ferret of Eurasia and North America living now? How far north is it found and in what kind of a climate is it there living now?
C. Richard Harington, Canada’s leading Pleistocene paleontologist, states: "At the gold placer site at Sixtymile, in the central western Yukon Territory, the carcass of the black-footed ferret has been recovered from the frozen ground. It has a Carbon-14 date of 39.56 yr B.P. The discovery of black-footed ferret remains in the Old Crow Basin and central Alaska strongly indicate the presence of dry grasslands with abundant rodents in those places during the Pleistocene. ... The preferred habitat of the species is arid short grass prairies or steppe, and is a good paleontological indicator of that kind of habitat." (1977:423)
Robert S. Hoffmann says in Arctic and Alpine Environments (1974) Table 9.2, under "Steppe-tundra mammals of the Late Pleistocene (Würm-Wisconsin)": Mustela eversmanni (= nigripes?) has lived in Europe, Siberia, Beringia, North America.
According to N. K. Vereshchagin and G. F. Baryshnikov (1984:487), the steppe-ferret Putorius eversmanni has lived during the late Pleistocene on the Russian Plain and Crimea, and in Siberia.
The Czech paleontologist Rudolf Musil (1985:31) states: "Putorius eversmanni prefers open landscapes, steppe to semi-deserts. Distribution: isolated finds throughout the Last Glacial."
Elaine Anderson (1977:6-9) reports about the steppe-ferret remains, recovered in Yukon/Alaska: "Mustela (Putorius) eversmanni Lesson, Steppe Ferret. Late Pleistocene, Fairbanks area, Alaska. - Anderson (1973) reported the presence of ferret in central Alaska. Additional studies show that the material is referable to Mustela eversmanni, the steppe ferret, an animal closely related to, if not conspecific with, Mustela nigripes the black-footed ferret. This is the first record of Mustela eversmanni in North America.
"Comparison of the Alaskan material with both Pleistocene and Recent Mustela (Putorius) nigripes Audubon and Bachman. Recent Mustela (Putorius) putorius Linnaeus showed that the specimens most closely resemble Mustela (Putorius) eversmanni michnoi Kashchenko, 1910, the South Transbaikalian Siberian Polecat. This is the largest subspecies and it inhabits the steppes south and west of Lake Baikal and neighboring areas of Mongolia (Stroganov, 1962). "Extant steppe- or Siberian ferrets are found in steppe and forest-steppe zones of Eurasia, from Hungary and Yugoslavia to the Amur region of Siberia, south to the plains of central Asia, Mongolia and northeast China (Stroganov, 1962).
"There is still disagreement as to the generic and specific status of Old World ferrets. Pocock (1936) and Ellerman and Morrison-Scott (1966) recognize a single species, Mustela (Putorius) putorius. However, Russian scientists (Ognev, 1931 and Stroganov, 1962), with larger samples to work with, recognize Putorius putorius and Putorius eversmanni as distinct species. There are also pronounced differences in body size, coloration and habitat of the two species. Mustela putorius inhabits forest biotopes and farmlands; Mustela eversmanni lives in the steppes and seldom enters forests. In areas where the ranges of the two species overlap, the two forms remain distinct.
"Pocock (1936:715) noted ‘the close similarity in all dimensions’ of a male skull of Mustela eversmanni from the Altai, and a male skull of Mustela nigripes from Montana. I took 26 measurements on 19 skulls of Mustela eversmanni and on 79 skulls of Mustela nigripes; there were no significant differences in size between the two species... Both species inhabit steppe regions, have a long sinuous body, and similar coloration. Mustela nigripes has never been abundant on the Great Plains, and today it is considered to be an endangered species. Unlike the steppe ferret (in Eurasia), which feeds on a wide variety of small animals, the black-footed ferret feeds primarily on Cynomys. The geographic range of Cynomys and Mustela nigripes are nearly identical and the two species are associated in most Pleistocene localities except Old Crow River; Cynomys has not been reported from Fairbanks. ... Ferrets entered the New World from Siberia across Beringia, and then advanced southwestward to the Great Plains through ice-free corridors." - Anderson, E. (1977:10).
Range of Black-footed ferret (Mustela nigripes) and North American badger (Taxidea taxus) during the late Pleistocene and now. After: R. D. Guthrie, Frozen Fauna of the Mammoth Steppe (1990:248, 249). Both of them are living now south of the subarctic zone of permafrost. When they were living in Alaska and the Yukon, together with the woolly mammoth, there has been then up there no permafrost either.
Yukon/Alaskan Glacial Climate
The remains of the steppe ferret Mustela (Putorius) evers-manni (= nigripes?) they have recovered in the Old Crow Basin, northern Yukon Territory, up to 68°N. They have also found them at Sixtymile, central western Yukon Territory, and in the Fairbanks area of central Alaska. This polecat was adapted to arid short grass prairies or steppes. The steppe ferret (or black-footed ferret) is supposed to have lived in Alaska and the Yukon during the Wisconsin/Würm Glaciation. How cold is it supposed to have been up there during the peak of the Last Glaciation? In what kind of a climate would this small carnivore have had to live then up there, together with the woolly mammoth, the lion and the badger?
During the Last Glaciation central Yukon/Alaska has been much colder, than it is now in northeastern Siberia. The permafrost was 800 m thick. It contained active ice wedges. Only a few centimeters of the frozen ground (the active layer) at the surface, were thawing in summer. The surface of the tundra in northern Yakutia is thawing now only 28-30 cm in summer, as N. K. Vereshchagin remarks.
The permafrost temperature in central Yukon/Alaska during the height of the Last Ice Age was –15°C. Ratio of permafrost temperature to mean annual air temperature is about 1.32. Permafrost temperature –15°C x 1.32 = -19.9°C mean annual air temperature in central Yukon/Alaska during the Last Ice Age. Alaska’s arctic tundra near the Arctic Ocean has now a mean annual air temperature of "only" –12°C. Siberia’s arctic tundra has now –16°C mean annual air temperature. Only the northernmost part of Greenland has now a mean annual air temperature of –20°C. (For climate of Last Glaciation see, please, Climate Atlas of Prof. B. Frenzel, 1992).
During the Last Ice Age the climatic snowline in central Alaska and the Yukon Territory was much lower than now. It was then 1000-1500 m or an average 1250 m above present sea level. Mean July air temperature was then 6.1°C (4.9-7.3°), at a lapse rate of 0.49%°/100 m (Péwé 1975). The summer was then much shorter, colder and wetter than now. And the frozen ground was covered with soggy arctic tundra, not with taiga, nor with short grass prairie or zonal steppe.
North America’s Black-footed ferret (Mustela nigripes). From: Grzimeks Tierleben (1972:756). This animal is adapted to the grassland, the prairie, where there is no permafrost, no ice and snow. According to C. R. Harington (1989:96) it has also lived during the late Pleistocene in central Alaska and the central and northern Yukon Territory, together with the woolly mammoth.
Eurasia’s Steppe ferret (Mustela eversmanni). Drawing from Grzimeks Tierleben (1972). It is closely related to the North American Black-footed ferret (Mustela nigripes). Some leading Pleistocene paleontologists are sure that the bones of the steppe-ferret, which they have found in Central Alaska and in the central and northern part of the Yukon Territory, are from the European steppe-ferret (Mustela eversmanni). This ferret is adapted to the open grassland, to the steppe, with its dry surface. It is living south of the limit of the continuous permafrost. That is, south of the subarctic zone. Also the Eurasian steppe-ferret proves that the mammoth has lived in the Far North, when there has been no permanently frozen ground up there, at least not close beneath the surface, when the climate was temperate, not arctic.
Present Climate at northern Limit of Range of Steppe Ferret.
North America. The black-footed ferret (Mustela nigripes) is living now in the grasslands of the central northern U.S.A. and southern Canada, up to about 52°N. In what kind of a climate is it living there at the northern limit of its range?
6°C mean annual air temperature, far below the southern limit of permafrost. 18°C mean air temperature of warmest month. 130 days above 10°C per year. 2000° temperature sum with days above 10°C (10°C.ts). 600 mm potential evapotranspiration (P.E.) per year. 40 kcal/cm² net radiation at earth’s surface.
Eurasia. Where the steppe ferret (Mustela eversmanni) is living now in Eurasia, at the northern limit of its present range, in what kind of a climate.
West Siberia. In West Siberia, the steppe ferret is living up to 57°-61°N, near the Ob River: 4°C mean ann. air temp., far below southern limit of permafrost. 1500° 10°C.ts. 100-110 days above 10°C. 400-450 mm P.E. 17°C July temperature. 25 kcal/cm² net radiation at earth’s surface.
Central Siberia. In central Siberia, the steppe ferret is living now up to 57°-58°N, south of the Angara River: 0° to 1°C mean ann. air temperature. No permafrost. 1000° 10°C.ts. 90 days per year above 10°C. 450 mm P.E. 17°C mean July temperature. 25 kcal/cm² net radiation at earth’s surface.
East Siberia. In East Siberia, the steppe ferret M. eversmanni is living now up to 53°N, east of Lake Baikal: -1°C to –2°C mean ann. air temperature. Only sporadic permafrost, up to 1 m thick. Active layer (ground on surface thawing in summer) up to 3 m deep (Jack D. Ives 1974). 1000° to 1200° 10°C.ts. 60 days above 10°C. 375 mm P.E. 12°C July temperature. 30 kcal/cm² net radiation at earth’s surface.
Lowest Temperature. The lowest temperature, at which the steppe ferret is still able to live now, at the northern limit of its range: -1° to –2°C ann. air temperature. 12°C July temperature, 90 days per year above 10°C. 1000° temperature sum with days above 10°C. 400-450 mm potential evapotranspiration. 25 kcal/cm² net radiation per year at earth’s surface. We should remember here: This climate at the northern limit of its present range is marginal habitat. The normal climate of the range of steppe ferret is warmer.
Present Arctic Tundra Climate. The animals of the mammoth fauna – with the steppe ferret -, are supposed to have lived in the Far North during the Last Glaciation. The climate in Yukon/Alaska is supposed to have been then much colder, than it is there up now. The present arctic tundra climate: -12° to –16° mean annual air temperature. Less than 60 day with days with a temperature of 10°C. 10 to 20 kcal/cm² net radiation per year at earth’s surface. 125 to 300 mm potential evapotranspiration (P.E.). Up to 300° temperature sum with days above 10°C. 4° to 12°C July temperature.
Result
The Eurasian steppe ferret and the North American black-footed ferret are not able to live in an arctic or subarctic climate. They are not able to live in an arctic tundra or tundra-steppe, because the ground is permanently frozen. In summer the surface is thawing only 28-30 cm deep. When the steppe ferret was living in Alaska and the Yukon Territory, together with the woolly mammoth, the lion and the badger, the climate was mild and temperate. The growing season of the plants was much longer up there than now. There was then no permafrost in Yukon/Alaska and no arctic winter.
Black-footed ferret (Mustela nigripes). Photo: K. Fagerstone. From: Milan Novak et al. (Eds.), Wild Furbearer Management and Conservation in North America. (1987:550) Fig. 1.