HA R D WICKE'S S CIENCE- G O SSI P. 



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THE MIGRATION OF THE LEMMING. 



IN ihQ Popular Science Review for April (an unusually 

 good number), we find a suggestive article, by 

 Mr. W. D. Crotch, M.A., F.L.S., on "The Norwe- 

 gian Lemming and its Migrations," in which the 

 author indulges in a bold and striking theory as to the 

 origin of these migrations. He thinks they point to 

 a lost page in the history of the world. It is certainly 

 most singular that instinct should seem to be so much 

 at fault as it is with these little animals. Instinct is 

 usually preset vaiive, but in the Lemmings it is highly 

 destructive, for Mr. Crotch tells us that every member 

 of the vast swarms which periodically devastate 

 Norway perishes voluntarily, or at least instinctively, 

 in the ocean. 



After describing the zoological characters and 

 general habits of the Lemming, Mr. Crotch shows 



a rug, merely because its ancestors found it necessary 

 thus to hollow out a couch in the long grass." 



Mr. Crotch goes on to seek for the " lost continent " 

 towards which the migratoiy instincts of the Lem- 

 mings still turn : — " Is it probable that land could 

 have existed where now the broad Atlantic rolls ? All 

 tradition says so : old Egyptian records speak of 

 Atlantis, as Strabo and others have told us. The 

 Sahara itself is the sand of an ancient sea, and the 

 shells which are found upon its surface prove that no 

 longer ago than the Miocene period, a sea rolled over 

 what is now a desert. The voyage of the Challenger 

 has proved the existence of three long ridges in the 

 Atlantic Ocean, one extending for more than three 

 thousand miles ; and lateral spurs may, by connecting 

 these ridges, account for the marvellous similarity of 

 the fauna of all the Atlantic islands. Moreover, I do 

 not suppose the Lemmings ever went so far south, 



Fig. 88. Croup of Lemmings {Myodcs Icnniiiis). 



that mere lack of food is not the cause of their migra- 

 tions. He thinks that it results from a former long- 

 continued habit, which was of benefit to them in 

 geological days, but destructive now that physical 

 geological changes have submerged the ancient goal 

 of the migrations. He illustrates the present habit of 

 the Lemmings by those of the swallows, which leave 

 us every year for Africa, and says, ' ' If the continent 

 of Africa were to become submerged, would not many 

 generations of swallows still follow their inherited 

 migratory instincts, and seek the land of their ancestors 

 through the new waste of waters? " It seems to the 

 author quite as probable that the impetus of migration 

 towards such a "lost continent should be retained, 

 a that a dog should turn round before lying down on 



though they are found as fossils in England ; but it is 

 a remarkable fact that whilst the soundings off Norway 

 are comparatively shallow for many miles, we find a 

 narrow but deep channel near Iceland, which probably 

 has prevented the Lemming from becoming indigenous 

 there, although an American species was found in 

 Greenland during the late Arctic expedition. If, as 

 is probable, the Gulf Stream formerly followed this 

 deep channel, its beneficent influence would only 

 extend a few miles from the coast, which would also 

 have reached to a great distance beyond the present 

 shores of Norway, and thus the Lemmings would have 

 acquired the habit of travelling westward in search of 

 better climate and more abundant food ; and as, little 

 by little, the ocean encroached on the land, the same 



