BRITISH MAMMALS 



abrupt prominence. The female is the smaller of the 

 two sexes, as, whilst she does not exceed 24 feet in length, 

 the male may attain as much as 30 feet. An excessive 

 development of the crest in the full-grown male at once 

 signifies its distinct appearance from that of its mate. 



The general colouration is light-brown above, with 

 greyish-white underneath, but the young are black 

 instead of light brown, and very aged specimens may be 

 distinguished by their almost yellow skin, banded with 

 white round the neck, and white is also present on the 

 front of the head and beak. 



This species undertakes remarkable migration journeys 

 in Winter from Northern to Southern seas, is most 

 faithful in its effort to stand by a wounded comrade, of 

 great activity of movement, and, when coming to the 

 surface, protrudes the foreparts of the body well out of 

 the water. As it descends to re-enter the water, it does 

 so head first, instead of allowing its bulky form to fall 

 helplessly into the sea, as in the larger Whales. Sper- 

 maceti, and an oil which is not unlike the valuable sperm 

 oil obtained from the Sperm Whale, are yielded by the 

 Bottle-nose, as much as two hundred weight of sper- 

 maceti, and two tons of oil, being obtained from an 

 adult male. 



It has the habit of remaining under water for long 

 periods, blowing heavily on reaching the surface, and 

 evidently hunting for food at great depths beneath. 



Common Porpoise. — As one watches the Porpoises 



(Fig. 25) patrolling close to the shore in the early days of 

 122 



