continuity of the Arcto-tertiary forest between the 

 two continents during tlie Tertiary ; tlie (Hssiniilarity 

 of s]iecies to divergent evolution since the two com- 

 munities became separated. 



Mammals common to the i-.uropean forest and 

 forest-edge include both the common and white- 

 toothed shrews, Kuropcan mole, common iiare and 

 luiropean rabbit, several mice, wolf (same species 

 as in North America), red fox (perhaps the same 

 species as in North America), weasels, wildcat, wild 

 boar, two deer, and European bison. 



The i)ird fauna ( luiropean fauna of Stegniann, 

 1938) includes some falcons, kites, and eagles, a 

 pigeon and a cuckoo, owls, several woodpeckers, a 

 jay, crows, several tits, a nuthatch, a creeper, a wren, 

 several thrushes, a rich variety of Old W'orld war- 

 blers only poorly represented in North America, an 

 Old World flycatcher not found in the New World, 

 an oriole, and various finches. Absent are the tyrant 

 flycatchers, vireos, and wood warblers that are so 

 prominent in the North American deciduous forest 

 (Lack and Venables 1939, Turcek 1951, 19.=;2. 1955). 

 Lists of invertebrates, especially of ground animals, 

 are given by Kiihnelt (1944). It is possible that 

 Pleistocene glaciation disturbed this biociation much 

 more than that in North America (Moreau 1954). 



Asiatic (leridiious jorcst biociation 



The broad-leaved deciduous forest of eastern 

 China, F"ormosa, Korea, and Japan contains many 

 species of plants and animals belonging to the same 

 genera as occur in Europe or North America. Dur- 

 ing the early Tertiary, this forest was in direct con- 

 tact, via the Bering land bridge, with that in North 

 America, and deciduous trees still maintain a narrow 

 and tenuous contact along the southern edge and in 

 serai stages of the coniferous forest with the decidu- 

 ous forest of Europe. In addition, there are some 

 endemic genera of animals confined to the area. A 

 number of Indo-Malayan species penetrate into the 

 biociation as far as northern China and Japan. Steg- 

 mann (1938) gives a list of bird species occurring in 

 this area that belong to what he calls the Chinese 

 fauna, but he does not distinguish between those 

 characteristic of forest, forest-edge, and serai com- 

 munities. 



ANLMAL ADJUSTMENTS 



Animals are adapted structurally, func- 

 tionally, and behaviorally to live in or under trees. 

 They may use the trees directly as lookouts, singing 

 posts, nest-sites, for cover and protection, and as a 

 source of food ; or they may simply take advantage of 



the rich humus created by the annual fall of leaves, 

 or the shade, greater humidity, and ecjuable temjier- 

 atures of the forest habitat. Some animals, for in- 

 stance the eastern chi])nnmk, die within a few minutes 

 if exposed directly to the sun. Snails and slugs are 

 most active and carry on their re])roductive activities 

 during the moist vernal aspect, but may be con- 

 .spicuous throughout the summer when they are able 

 to maintain the necessary water balance. 



Special adaptations for arboreal habits and for 

 climbing are the sucking discs on the toes of tree 

 frogs, the sharp claws and opposable toes in wood- 

 peckers and squirrels, the prehensile tails of oppos- 

 sums and white-footed mice, the parachutes and 

 bushy tails of squirrels as well as the movable scales 

 of some of the snakes, the many legs of the millipedes, 

 and the slimy feet of slugs and snails. 



Hearing and voice are well developed in many 

 forest animals, although vision is less perfected since 

 visibility is limited anyway. The rich and almost con- 

 stant singing of forest birds throughout the breeding 

 season is well known, but the voice, or songs, of 

 squirrels, chipmunks, and wolves are also well de- 

 veloped for mammals. The loud singing of tree frogs 

 is noteworthy, and the nightly chorus of insect voices, 

 especially those of orthopterans, is remarkable. Most 

 of these sounds serve to attract mates or advertise 

 territories. 



The regular and pronounced changes in photo- 

 period and temperature bring full development of 

 the breeding season of most animals to its peak dur- 

 ing the spring and early summer. Deer, bats, and a 

 few others, however, characteristically mate during 

 the autumn, and some of the squirrels and owls dur- 

 ing the winter. 



All species must meet the severe winter condi- 

 tions of short days, low temperatures, and scarcity 

 of food in one way or another. In those forms of 

 mammals and birds that remain active over winter 

 and in those insects that hiberate in exposed situa- 

 tions there is considerable increase in resistance to 

 cold by internal physiological adjustments, and they 

 live either on kinds of food that are not usually con- 

 cealed by snow or on food cached when it was plenti- 

 ful. Mammals den up in hollow logs or trees during 

 short severe cold periods, coming out again when the 

 weather is mild. Flocking is common in most birds 

 during the winter season in contrast to their isolation 

 in territories during the breeding season. Flocks 

 commonly seek shelter on the lee side of forest areas 

 or in river valleys to get protection from cold winds. 

 Populations and variety of birds are supplemented 

 during the winter as northern species come South. 



Those species of birds, mammals, reptiles, am- 

 phibians, insects, and snails that cannot maintain 

 activity in winter conditions either migrate or hiber- 

 nate. Migration among birds commonly reduces the 



Temperate deciduous forest biome 299 



