ECOLOGICAL FACTORS 387 



The footnotes offer an explanation for the apparent exceptions. 

 A giant form of the puffin, Fratercula arctica naumanni (wing length 

 175-195 mm.), lives in Spitsbergen and north Greenland; these birds 

 are smaller on Bear Island, on the Norwegian coast, in Iceland, and 

 south Greenland (wing length 158-177 mm.) ; and still smaller (wing 

 length 155-166 mm.) on the Channel Islands and Helgoland, while a 

 dwarfed form (wing length 135-145 mm.) winters in Mallorca. 27 The 

 horned larks of North America exhibit a graduated series of subspecies; 

 those from Hudson Bay have a wing length of 111.5 mm., those from 

 Kansas and Nebraska measure 105.8 mm., those from Nevada, 102.9 

 mm., the coast inhabitants of Lower California, 99.1 mm., and finally 

 those of Santa Barbara Island near California have a wing length of 

 97.1 mm. 28 Hummingbirds that live in the greater altitudes of the 

 Andes have a minimum body length of 45 mm., and the largest species, 

 Patagona gigas, goes farthest south; a very small species, one of the 

 smallest of birds, Chaetocercus bombus, with a body length of 28-28.5 

 mm., inhabits Ecuador and northern Peru, just south of the equator. 

 When the same species inhabits different climates, the individuals tend 

 to attain the largest size in the coolest regions; thus Chlorostilbon aure- 

 oventris in Paraguay and north Argentina is larger than in southeastern 

 Brazil and is smallest in central Brazil. Countless other examples may 

 be found in the literature. 26, 29 ~ 32 



Mammals verify the same theory; the larger mammals of central 

 Europe increase in size toward the northeast and decrease in size to- 

 ward the southwest, as is shown by the red deer, roe deer, fox, wolf, 

 and wild boar. The skull length of the wild boar varies as follows: 

 those from southern Spain 324 mm., from northern Spain 353 mm., 

 from the Pyrenees to Germany 380-410 mm., from Transylvania 452 

 mm., from White Russia 465- mm., 33 from east Siberia 560 mm. The 

 average basal length of the skull of the alpine hare {Lepus timidus) 

 varies similarly: in Ireland it is 73 mm., in Scotland 70 mm., in 

 Scandinavia 73.2 mm., in north Scandinavia and Russia 77.8 mm., on 

 Yezo (Japan) 80 mm., in northern Siberia 87.5 mm. 34 For the mole 

 rat, Spalax, there are three districts based upon the size of the species: 

 (1) small forms from Tripoli, Egypt, Palestine, and Syria; (2) 

 medium-sized forms from Asia Minor, Transcaucasia, Balkan Penin- 

 sula, Dobruja, and Hungary; (3) large forms from Galicia, Buko- 

 wina, southern Russia, Cis-Caucasia, and from the Kirghiz Steppes. 35 

 The pocket gopher, Geomys bursarius, of North America north of 46° 

 N. latitude attains a total length of 296 mm., between the latitudes of 

 40° and 46° only 284 mm., and south of 40°, 256 mm. 36 The length of 

 the skull in the American mole, Scalops aquaticus, in millimeters 



