most frci|iicinly in tlic lioiirs before midnight, but 

 the periods of rest are shorter tlian in soutliern lati- 

 tudes (Armstrong 1954, CuUen 1954). In one study 

 conducted above the Arctic Circle, adult robins fed 

 their young for 21 hours per day and the young birds 

 grew so rapidly that they left the nest in 8.8 days 

 instead of the 13 days usual in more southerly lati- 

 tudes (Karplus 1949). During the winter, there is 

 at least a faint glow of light for an hour or two at 

 noon. It is during this period that ptarmigan and 

 l)robably other birds feed most heavily (Gelting 

 1937). As a rule, northern birds also tend to lay 

 larger clutches of eggs than their closest relatives in 

 southern latitudes (Lack 1947-1948). Related to 

 their nesting is the tendency for many species to have 

 flight songs, sometimes given high in the air, for 

 announcing the possession of territories and for so- 

 liciting mates. This development of behavior is re- 

 lated to the lack of high song posts and is similarly 

 developed in the grassland biome. 



A final characteristic of these northern animals is 

 their fearlessness of man. The few Eskimos, Indians, 

 and white men who inhabit the tundra are so scat- 

 tered that animals in general have not learned to fear 

 them. To a certain extent this is true also of some 

 boreal forest species ; snow buntings, snowy owls, 

 grosbeaks, crossbills, and other species may be ap- 

 proached closely before they are moved to flee. 

 Among mammals, individual arctic foxes not infre- 

 quently linger close to human habitation for days 

 at a time. 



winter in search of pasture for their animals, north- 

 wards and southwards with the seasons for fishing; 

 below tree-line they occasionally grow meager crops. 



.ALI'INK Tl'NDR.A BIUCIATION 



TibrUin jaciation 



The largest alpine areas of the world lie on the 

 Tibet Plateau and in the adjacent Himalayan Moun- 

 tains of Asia (Hingston 1925, Schafer 1938). Oc- 

 curring here are related forms of pikas, pipits, rosy 

 finches, and horned larks also found in mountain 

 areas of the western hemisphere, while the marmot 

 and sheep may be conspecific with North American 

 forms (Rausch 1953). 



Stegmann (1938) gives a long list of birds espe- 

 cially characteristic of the Tibetan fauna. The Tibet 

 Plateau may represent an important center of origin 

 of alpine species, some of which then became dis- 

 persed into the higher mountains of Europe and 

 North America. The Tibetan fauna evolved inde- 

 pendently from that of the Arctic tundra and there 

 are few or no bird species common to the two. There 

 is some overlap of species, however, with the Asiatic 

 grassland (Mongolian fauna), Asiatic deciduous for- 

 est ( Chinese fauna ) , and Ethiopian desert ( Medi- 

 terranean fauna) biociations which suggests their 

 possible remote derivation. 



uman re, 



lati 



The arctic is the home of Eskimos in North 

 America and of the Lapps in Eurasia (Hadlow 1953, 

 Freuchen and Salomonsen 1958). The Eskimos are 

 concentrated along the coast as much of their food 

 comes from the sea : fish, walrus, seal, and polar bear. 

 During the summer, caribpu flesh, bird eggs, and 

 berries are eaten. Caribou fat and seal oil are burned 

 in the Eskimo igloos to furnish light and heat, and 

 pelts from these animals are made into clothing and 

 blankets. Meat is eaten either cooked, dried, or raw, 

 and some of it is frozen and buried in the ground 

 for the winter days of scarcity. The Eskimo gets his 

 transportation during the summer in light boats made 

 of sealskin stretched over frameworks of driftwood 

 or bone, and during the winter in sleds drawn by 

 dogs. Fur trapping is the chief source of income. 



The Lapp lives much like the Eskimo, although 

 he more commonly lives in a tent made of reindeer 

 skin than in an igloo made of snow. The reindeer is 

 used by the Lapp for pulling his sled, for meat, and 

 for milk. The Lapp may also keep goats. Lapps 

 move up and down the mountains in summer and 



North American f aviation 



Because of its small total area, rugged terrain, 

 and discontinuity between mountain peaks, there are 

 only a few species characteristic of the alpine tundra 

 in North America. 



Mammals are conveniently divided into two 

 groups. Those occurring in the high tundra from 

 Alaska to British Columbia are the collared pika, 

 hoary marmot, singing vole, barren ground caribou, 

 mountain goat, and Dall's sheep. Species limited to 

 the southern mountains are common pika, yellow- 

 bellied marmot, and mountain sheep. The common 

 pika is differentiated into over thirty subspecies in 

 the various mountain areas. .Shrews, bears, coyotes, 

 weasels, badgers, mice, wapiti, and mule deer of the 

 western montane biociation range up into the alpine 

 tundra during the summer. Ground squirrels and 

 pocket gophers reach this community south of Canada 

 by extending their ranges from the low elevation 

 grasslands through serai stages in the intervening 

 coniferous forests. 



Of birds, the white-tailed ptarmigan, water pipit, 

 and gray-crowned rosy finch are characteristic and 

 widely dispersed. In the central and southern Rocky 



Tundra biome 32' 



