388 ABSENCE OE TERRESTRIAL 



ABSENCE OF BATRACHIANS AND TERRESTRIAL MAMMALS ON 



OCEANIC ISLANDS. 



With respect to the absence of whole orders of animals 

 on oceanic islands, Bory St. Vincent long ago remarked that 

 Batrachians (frogs, toads, newts) are never found on any of 

 the many islands with which the great oceans are studded. 

 I have taken pains to verify this assertion, and have found 

 it true, with the exception of New Zealand, New Caledonia, 

 the Andaman Islands, and perhaps the Solomon Islands and 

 the Seychelles. But I have already remarked that it is 

 doubtful whether New Zealand and New Caledonia ought to 

 be classed as oceanic islands ; and this is still more doubtful 

 with respect to the Andaman and Solomon groups and the 

 Seychelles. This general absence of frogs, toads, and newts 

 on so many true oceanic islands cannot be accounted for by 

 their physical conditions : indeed, it seems that islands are 

 peculiarly fitted for these animals ; for frogs have been 

 introduced into Madeira, the Azores, and Mauritius, and 

 have multiplied so as to become a nuisance. But as these 

 animals and their spawn are immediately killed (with the 

 exception, as far as known, of one Indian species) by sea- 

 water, there would be great difficulty in their transportal 

 across the sea, and therefore we can see why they do not 

 exist on strictly oceanic islands. But why, on the theory of 

 creation, they should not have been created there, it would 

 be very difficult to explain. 



Mammals offer another and similar case. I have carefully 

 searched the oldest voyages, and have not found a single 

 instance, free from doubt, of a terrestrial mammal (exclud- 

 ing domesticated animals kept by the natives) inhabiting an 

 island situated about 300 miles from a continent or great 

 continental island ; and many islands situated at a much less 

 distance are equally barren. The Falkland Islands, which 

 are inhabited by a wolf-like fox, come nearest to an excep- 

 tion ; but this group cannot be considered as oceanic, as it 

 lies on a bank in connection with the mainland at a distance 

 of about 280 miles ; moreover, icebergs formerly brought 

 bowlders to its western shores, and they may have formerly 

 transported foxes, as now frequently happens in the arctic 

 regions. Yet it cannot be said that small islands will not 

 support at least small mammals, for they occur in many 

 parts of the world on very small islands, when lying close 



