WHY DO ANIMALS BECOME EXTINCT? 181 



brought in, it was found that the majority of these were 

 tile-fish, while from the reports of various vessels it 

 was shown that the area covered by dead fish amounted 

 to somewhere between 5,000 and 7,500 square miles, 

 and the total number of dead was estimated at not far 

 from a billion. This enormous and widespread destruc- 

 tion is believed to have been caused by an unwonted 

 duration of northerly and easterly winds, which drove 

 the cold arctic current inshore and southwards, chilling 

 the warm belt in which the tile-fish resided and kilUng 

 all in that locality. It was thought possible that the 

 entire race might have been destroyed, but, while none 

 were taken for many years, in 1899 and in 1900 a 

 number were caught, showing that the species was be- 

 ginning to reoccupy the waters from which it had been 

 driven years before, and since then it has become rela- 

 tively abundant. 



The effect of any great fall in temperature on animals 

 specially adapted to a warm climate is also illustrated 

 by the destruction of the Manatees in the Sebastian 

 River, Florida, by the winter of 1894-95, which came 

 very near exterminating this species. Readers may re- 

 member that this was the winter that ^Tought such 

 havoc with the blue-birds, while in the vicinity of Wash- 

 ington, D. C, the fish-crows died by hundreds, if not by 

 thousands. 



Fishes may also be exterminated over large areas by 

 outbursts of poisonous gases from submarine volcanoes, 

 or more rarely by some vast lava flood pouring into the 

 sea and actually cooking all living beings in the vicinity. 

 And in the past these outbreaks took place on a much 

 larger scale than now, and naturally wrought more 

 widespread destruction. 



A recent instance of local extermination is the total 

 destruction of a humming-bird, Bellona ornata, peculiar 



