302 WHALES AND DOLPHINS 



The teeth number 3 to 7 on each half of the lower jaw. 

 They are usually wanting altogether in the upper jaw, but 

 very occasionally a tooth or two may be found there. The 

 lower jaw teeth in the adult are quite conspicuous objects, 

 more than \ inch in diameter at the gum and projecting from 

 it about f inch. They are placed near the tip of the jaw, the 

 space occupied by them being only about a fifth of the jaw 

 length. 



The adult length is 12 to 13 feet. 



Risso's Dolphin is widely distributed ; it is known to occur 

 in the North Atlantic and Mediterranean, and in the southern 

 hemisphere it has been recorded from the coast of New Zealand 

 and at the Cape of Good Hope. 



The animals stranded on the British coast, 45 in the last 

 thirty-three years, have been concentrated in the south and 

 west, very rarely on the east coast ; this distribution points 

 to the Atlantic origin of the British specimens. British 

 strandings have been most common in the summer months., 

 and it is likely that this species, like so many others, undertakes 

 migrations which bring it into higher latitudes during the 

 warmer months of the year. 



It occurs solitarily or in small schools of less than a dozen. 

 Cuttlefishes are, so far as is known, the only food of this 

 species. 



Little is known about the breeding habits of Risso's Dolphin, 

 but an indication that parturition takes place about the end 

 of the year is given by a specimen found in December. It 

 carried a full-time foetus, 5 feet 5! inches long, or more than 

 half the length of the 10 foot 6 inch parent. It should be 

 said, however, that the unborn calf lies with its tail curled 

 round under its body, so that the total length when the tail is 

 extended gives a false impression of the bulk of the foetus as 

 compared with that of the mother. 



In a young specimen described by Sir William Flower, the 

 upper lip on either side bore 8 whitish bristles arranged in 

 two rows, 6 in the lower and 2 in the upper. 



The celebrated Pelorus Jack was a Risso's Dolphin which 

 haunted Pelorus Sound, and used to swim at the bows of ships 

 on the route between Nelson and Wellington, New Zealand. 

 So well known was it that it was protected by Order in Council. 



