THE SPINY ANT-EATER or 

 ECHIDNA 



(Tackyglossus aculeatus) 



NO one who looked at the portrait of the spiny ant-eater for the first time, 

 and had no knowledge of its anatomy or history, would be likely to guess 

 that it was a near relative of the duckbill. But in natural history, when 

 we have to deal with members of different groups, externals count for very little, 

 and all depends upon internal organisation. In the latter respect the echidnas, for 

 there is more than one species, resemble in all essential features the duckbill, as 

 they do in laying hard-shelled eggs, from which the young are eventually hatched. 

 The single egg of the echidna, in place of being laid in a burrow, is, however, carried 

 about by the female in a pouch developed for the purpose on the under side of her 

 body shortly before the egg is laid ; and in this same temporary pouch the young 

 is likewise nurtured during the earlier stages of its existence. 



The duckbill and the echidna afford an excellent example of the diversity 

 of appearance produced in animals more or less nearly related to each other by 

 specialisation and adaptation to totally distinct modes of life. In the duckbill the 

 specialisation and adaptation are for an aquatic existence ; in the echidna they are 

 for a burrowing, terrestrial life and a diet of ants. 



To an ant-eater teeth of any kind would be not only useless, but an actual 

 hindrance, and they have accordingly been discarded, while the muzzle has been 

 prolonged into a decidedly bird-like beak. In this respect the echidna much 

 resembles the great South American ant-eater, which belongs to a totally different 

 group of mammals. 



To enable it to dig out the nests of the ants which form its chief food, and 

 likewise to excavate the burrows in which it passes the day, the echidna is armed 

 with powerful claws, those on the hind-feet being, however, much larger and more 

 curved than those in front. It is with these strong hind-claws that the earth 

 loosened by the fore-feet is thrown out from ants' nests and the burrow. Like 

 the porcupine, which is also a nocturnal and a burrowing creature, the echidna 

 has its back protected with an array of parti-coloured horny spines mingled with 

 hairs. The degree of development of the spines is, however, subject to great varia- 

 tion ; and there is one race in which the hair predominates, and the spines appear 

 only in the midst of the dense brown fur. Like the platypus, the echidna has no 

 external ears. 



The ordinary, or five-toed, echidna has a much more extensive range than 



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