. 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 th
. 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
Size: 7016px × 713px
Photo credit: © The Bookworm Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, booksubjectocean, booksubjectscientificexpediti
