APPEARANCE AT THE SURFACE 117 



slower than the whale in fig. 2 of the same plate. As a result of further flexure, which can sometimes 

 be seen to be effected by muscles of the back, the mid part of the body travels through the arc set by the 

 head and neck (Fig. i h). As the whale travels forward, the trunk and fin rise out of the water (Fig. i /, 

 andy); then, giving place to the caudal peduncle, the trunk begins to sink (Fig. \k, I). The general 

 effect after the dipping of the head is that of a wheeling motion of the back out of the sea and into it 

 again. But the fin, having wheeled out of the water, acquires a cam-like action and having reached its 

 zenith, the wheeling motion stops. The outstanding parts now slowly sink, travelling forwards slowly. 

 The caudal peduncle submerges, together with the posterior part of the trunk, and the fin is generally 

 the last to disappear from view (Fig. i m). The fin and caudal peduncle often disappear simultaneously, 

 but the peduncle seldom by itself and then only when the angle of diving is unusually steep. A whale 

 blowing in this manner offers the best target not only because the movement is comparatively slow 

 but also because the head, trunk and caudal peduncle are well elevated. 



Fig. I. Diagrams illustrating the appearances of Fin whales at the surface; based on photographs and notes, and on a drawing 

 by J. F. G. Wheeler (Mackintosh and Wheeler, 1929). a-c, whale blowing leisurely; d-m, at medium speed; n-p, fast. 



The whale may go through these motions faster or slower, a period of 40—6 sec. elapsing between the 

 act of blowing and the disappearance of the dorsal fin (5I-7 sec. overall). A whale in a hurry blows off 

 air before reaching the surface and a dome of silvery bubbles momentarily appears over the back of the 

 neck. According to the speed of blowing depends the splash. A whale shooting its head out of the 

 water fast, sometimes lets it down fast and the surface splash, accompanied by waves, spreads several 

 yards to right and left. Disappearance of the fin and caudal peduncle, however, is unattended by 

 splash. 



Here it may be convenient to refer to the so-called 'oily patch' (or 'slick'. True, 1903) left by the 

 whales at the surface after their disappearance. The smoothness of these patches resembles closely 

 the wake of a steamship, and the welling which is observed in them is doubtless produced by the tail 

 flukes and affords useful evidence of their action. 



(iii) Fast. When blowing is brisk, the whale appears and disappears so quickly (3-3! sec.) that the 

 details of its movement are hard to pick up and whales breaking surface in this way have not, during 

 this whale-marking commission, been spotted beneath the surface beforehand. The whale appears 

 suddenly and simultaneously blows. The tip of the snout is again the first part to emerge and the head 

 shows above water for little more than a second as before. The movements are probably similar to 

 those undergone in breaking surface at medium speed, but carried out with greater impetus. The body 



