96 ANIMAL LIFE IN DESERTS 



them to survive drought in a remarkable manner. 



That frogs are able to exist at all in temporary 

 waters in Central Australia is very remarkable, 

 because their need for water is great, and their 

 damp skins are entirely unsuited to Ufe in a dry 

 atmosphere, in which they invariably die. Six 

 species were found in the desert region, but two 

 were rare and little was discovered about their 

 habits. The remaining four all showed different 

 interesting methods of overcoming the hostiUty of 

 their environment. They were all of them able to 

 spawn at any time of year, as soon as rain had fallen. 



Hyla rubella^ a close relative of the green Treefrog 

 of Southern Europe, was found in nearly every 

 water-hole which was visited during the dry season. 

 It appears that it does not burrow in damp soil, 

 and therefore when its water-hole dries up it perishes. 

 On the other hand, it is a very rapid breeder, and if 

 rain falls heavily its tadpoles are carried down the 

 channels and its range is, for the moment, very 

 greatly increased. It is therefore a species which 

 depends for its success in colonizing Central AustraUa 

 on its abiHty to produce its young rapidly and in 

 large numbers : it might be said to be successful 

 because its high birth-rate after rain exceeds its 

 high death-rate diu-ing the dry weather. If the 

 drought exterminates a colony of this frog at a 

 certain water-hole in the bed of a stream, the next 

 flood will enable the species to colonize the same 

 spot once again from a permanent pool. 



Another common frog was Limnodynastes ornatus. 

 Like many of the frogs of the more arid parts of 



