314 ECOLOGY 
physiologically similar to some antelopes. As has already been stated, 
the zodlogist is usually unduly impressed with specificities such as mode 
of movement of limbs, body, etc. Now if my reader pictures an African 
antelope running gracefully from a pack of Cape hunting dogs (102, 
pp. 119-23), and an old-man-kangaroo leaping from a pack of dingoes 
(202, pp. 41, 243), noting mainly the specific peculiarities of the movement 
of limbs and body of the pursued in each case, he will be dwelling upon 
specificities of little ecological significance and missing the point of view 
of the ecologist altogether. These specificities of behavior are matters of 
little ecological significance; it matters not if one animal progresses by 
sommersaults so long as the two are in agreement in the matter of reac- 
tions to physical factors as indicated by the manner of spending the day 
(200), avoidance of forests, swamps, cold mountain tops, etc., entirely 
available to them, and in the mode of meeting enemies as indicated by the 
reaction to the approaching hunter or enemy. 
a) Distribution of land communities represented in Central North 
America.—The following climatic formations are represented at Chicago 
and distributed as given below: 
Temperate Deciduous Forest Formations: Forest with broad, thin leaves which 
are shed in autumn; near Chicago, oak, hickory, beech, and maple (58a). 
Distribution: Eastern North America, north to the Great Lakes; 
Chili, north to 35°; Europe, north of the Alps, and south of 60°; 
Japan and the vicinity of Okhotsk (58a). 
Temperate Savanna Formations: Grasslands with scattered trees, or trees in 
groves surrounded by thickets, and with dense forests along larger streams. 
Near Chicago, the grassland is prairie and the trees chiefly oak and hickory. 
Distribution: A narrow belt in North America surrounding the great 
plains on the east; north, and west; Uruguay, South Australia, 
South Africa, and Eastern Siberia. 
Formations of Forests with Narrow Thick Leaves: Coniferous forest. Dense 
evergreen forests with little undergrowth. Lies just to the north of 
Chicago and was represented locally in the parts of Michigan shown on 
Map I (frontispiece). 
Distribution: North America north of the Great Lakes and Columbia 
River extending southward into the mountains; Eurasia north 
of 60°, extending southward into the mountains. 
The localities which are in agreement are indicated by distribution 
of the different types of formation. It will be noted that the deciduous 
forest animal formation with which we have dealt is found in several 
parts of the world, this animal community being essentially duplicated in 
