WHALES AND DOLPHINS. 



ance is accordingly produced only by the con- 

 densation in the colder air of the vapour ex- 

 pelled from the lungs through the blow-holes. 

 A large whale, which I saw pass my window 

 at Nice daily for three weeks, only shot up 

 an insignificant jet, which often was not visible 

 at all. The air was warmer. Only when 

 the animals are pursued, and begin to breathe 

 while the blow-hole is still beneath the surface, 

 is there any water carried up into the air 

 along with the vapour. 



This process of breathing lasts only a few 

 seconds. The head is then again submerged, 

 the back and dorsal fin appear for an instant 

 describing a curve above the surface, and at 

 last the tail fin momentarily appears, but is 

 again immediately submerged while the head 

 is raised anew. A shoal of dolphins swim- 

 ming close behind one another in a row pro- 

 duces, in a wonderfully deceptive manner, the 

 appearance of a large serpent swimming on 

 the surface of the water by means of vertical 

 undulations. 



All whales are exclusively carnivorous and 

 very voracious. Some feed on fish, others 

 on calamaries and cuttle-fishes, others again 

 on crustaceans and molluscs. The kind of 

 food is not always in proportion to the size 

 of the ravager; numbers must make up for 

 deficiency in size. The Greenland or right 

 whale swallows pteropods, a small kind of 

 naked mollusc, in tons, and the rorqual pur- 

 sues shoals of herrings into bays or the shores, 

 and commits frightful ravages amongst them. 

 The small species are much dreaded by fisher- 

 men on account of the injury they do to their 

 nets, the large ones are energetically pursued 

 for the oil which they yield. 



It appears that the whales propagate their 

 kind at all seasons, for embryos have been 

 found in the mothers at different seasons in 

 the same stage of development. But nothing 

 is known either about the congress of the 

 sexes or the birth of the young. After birth 

 the young follow the mother about for a little, 

 and on the appearance of danger are taken 



by the latter, who is ready to sacrifice her life 

 for her offspring, under her fin, as shown in 

 Plate XVI. 



We divide the order of the Cetacea into 

 two groups, the Toothed Whales (Denticete), 

 which have teeth in the adult forms, and 

 Whale-bone Whales (Mysticete), in which 

 the teeth are replaced by whalebone. 



THE TOOTHED WHALES 



(DENTICETE). 



The Dolphins (Ddphinida). 



> 

 The toothed whales comprise first of all the 



True Dolphins (Delphinida), which have a 

 larger or smaller number of uniform teeth in 

 both jaws and feed exclusively on fishes. 



The Fresh-water Dolphin, the Susuk of 

 the Hindus (Platanista gangctica], fig. 131, 

 belongs to this stock. It is found in the 

 Ganges and its tributaries, and also in the 

 Indus, ascends pretty far up into the land, 

 although it is always most abundant near 

 the mouth. It is distinguished from other 

 dolphins by its long thin beak slightly curved 

 upwards, which has along the middle line a 

 longitudinal ridge separating the narrow slits 

 which form the blow-holes. It has about 32 

 slightly recurved conical teeth, which become 

 longer near the point of the beak. The 

 dorsal fin is in the form of a low triangular 

 lobe. The tail fin is deeply two-lobed. The 

 animal attains a length of only 6^ feet. 

 The back is almost black. It is said to make 

 use of its beak to dig among the cane-thickets 

 on the river-banks. Its fat is used as a 

 salve. 



The large rivers of South America, 

 especially the Amazon and the Orinoco, 

 appear to be inhabited by several species 

 of long-beaked dolphins, among which the 

 species called by the natives the Inia, Bonto, 

 or Amazon Dolphin (Ima amazonica (geof- 

 frensis)}, fig. 132, is the best known. The 

 beak is straight and narrow, and, unlike what 

 we find in other whales, is set with short stiff 



