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1

APPENDICES.

89

Black-bellied, 3.

19th December (59, fœtus 1 ft. 4 in.). 31st December (153, fœtus 1 ft. 5 in.). 15th January (288, fœtus 2 ft. 1 in.). Colour not noted, 2.

24th December (97, fœtus ? length). 30th December (136, fœtus 2 ft. 1 in.).

Of 4 no note as to pregnancy is given :-

White-bellied, 1.

31st December (151). Marble-bellied, 1.

26th December (108).

Black-bellied, 2.

31st December (152).

12th January (260).

One was an impregnated heifer :--

Black-bellied, 1.

18th December (54, length, 43-75 ft.).

Ten of these 32 whales were immature (virgins)

Their lengths ranged from 275 to 41 ft. 10-100

White-bellied, 1

10-313 per cent.

Per cent.

100

1- 10

16th January (297, 41 ft.).

Marble-bellied, 5

5= 50

8th January (222, 33·25 ft.).

9th January (238, 40 ft.; 239, 36-5 ft.).

10th January (249, 33 ft.).

18th January (295, 27.5 ft.).

Black-bellied, 4

4= |!

18th December (52, 38-25 ft.). 5th January (181, 39-75 ft.). 7th January (210, 34 ft.). 14th January (276, 33 ft.).

100

BREEDING AND MIGRATION.

It is now a well-ascertained fact that the humpback whales of both the North and the South Atlantic undertake each year great migrations along rather well- These migrations are so closely connected with defined courses at regular seasons.

the breeding habits of the humpbacks that it is necessary to review our knowledge of them before discussing the many important and complex questions involved in any attempt to determine the time and duration of the sexual season.

The best accounts of these migrations that have been published hitherto are those given by Professor Collett in his book on the mammals of Norway, and by Rist- The former author naturally says com ing, in a paper on the humpback whale.

paratively little about the humpbacks of the South Atlantic; but Risting gives a very full description of their migrations, and his paper is so frank and important when considered in connexion with the objects of Major Barrett-Hamilton's mis- sion to South Georgia that I have thought it necessary to make a translation which is appended to this report (Appendix II., p. 180).

Two annual movements of the humpbacks are described by these authors. The On this the whales proceed from the first is called the "breeding-migration." polar seas to sub-tropical or equatorial waters, where the young are born and where pairing is supposed to take place shortly after parturition. It is a controverted question (discussed below) whether the females which have just cast their young share in this pairing, or whether it is confined to those which either are not nursing or are about to wean their calves.

Owing to the scarcity of whale-food in the warm seas the sojourn of the bump- backs in the tropics is a short one, and they return, on their "feeding-migration," to the sub-polar waters, where a rich growth of plankton, called forth by the peculiar combination of light and cold which forms the polar summer, furnishes an ample and attractive provender.

The northern humpbacks, journeying westwards from the eastern portions of the Arctic Ocean, pass along the coast of Finmark in the months of January, February, and the early part of March. At this time they are fat, and the preg nant females normally contain large foetuses, the latter being evidently near the end of their intra-uterine existence. Their progress is described as normally rapid and restless, the whales not usually stopping to feed, and their course is so close inshore that they sometimes run aground. The whalers believe that the whales purposely travel in the shallow water in order that friction with the rocks may free them of the many ecto-parasites with which they are infested. About this time numbers of humpbacks are found also off Bear Island, Jan Mayen, and to the north of Iceland.

In the early spring, usually in April, these northern herds migrate southwards to give birth to their young in the warmer parts of the North Atlantic. From March to May females with new-born calves are seen in the neighbourhood of Bermuda, the Azores, the Cape Verde Islands, and off the north-western coast of Africa. These northern humpbacks thus migrate as far south as about 15o North latitude, but there does not appear to be any evidence of their crossing the equator.

After the birth of the young the humpbacks commence to migrate northwards The foetuses again. Many of the females are now accompanied by small calves. found at this time are of small size. Mörch states that in July the calves are about The course of 20 ft. long, and that the length of the foetuses is about 20 in. this, the "feeding-migration," is stated to be generally from south-west to north- east, so that it rarely touches the home waters of the southern parts of the west European coast.* At the stations on the west coast of Ireland and the Hebrides a few individuals are caught in some vears; at those in the Shetlands and Faroes they are found to be more regular in their appearance at this season, although not common. On the American side of the Atlantic a corresponding migration occurs at this season, the humpbacks being abundant in the Greenland Sea during summer and early autumn. On their arrival in northern latitudes the humpbacks busy themselves principally with the search for food, feeding partly in the plankton- bearing currents and partly in the herring shoals. Arriving in the neighbourhood of such foods their progress becomes more leisurely, and they commonly remain off the coasts of Iceland and Finmark until the approach of autumn.

Risting mentions that in the course of whaling at Finmark it was observed that towards autumn the humpbacks. still engaged with the search for food, moved north- wards to the seas around Bear Island and below Spitzbergen. Later when, owing to the chilling of the surface water, the capelan descend to greater depths and whale- food becomes scarce, the humpbacks move into the eastern and more open parts of the Arctic Ocean, where they usually pass the winter, feeding during this season, at all events partly, upon the herring shoals.

Since there is evidence of the segregation of the herds in "schools" of similar individuals, the fact that definite migrations take place is sufficient to explain the rather striking differences which the individuals captured at certain times in certain localities present, when compared with the individuals caught at other times, and/ or in other localities. Thus, of 11 examples examined by True at Balena Station, Newfoundland, between 26th April and 6th July (7 between 7th and 30th May, 1000), 9 were males and 2 were females. Of these specimens only one, a male, 48 ft. 11. long (26th April), could be regarded as really mature: the others were all either large calves or else whales which were approaching or had just reached sexual maturity. In 1901 of 7 specimens (sex not recorded) captured at the same place between 7th May and 17th June (5 between 7th and 20th May), only 2 (46 and 47 ft. long) were mature: the others, with lengths ranging from 26 to 34 ft.. were calves. In August, 1899, 3 humpbacks were caught at Snook's Arm, Newfoundland, a male, 42 ft. 2 in., and 2 females, 45 ft. 5 in. and 46 ft. 6 in. long: the latter were pregnant with small fœtuses. True (op. cit., n. 111)"" was informed by Captain Bull that the humpback arrived in large numbers later in the year

"than August.

* Eschricht (" Zool.-anat-physiol. Untersuchungen usb. d. Nordischen Wallthiere," vol. 1. 1849, p. 176) records only two specimens as stranded on the European coast between 1824 and 1846.

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