. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. THE SEI WHALE 253 and April. Parturition and lactation appear to take place in temperate latitudes and lactation generally appears to be completed by the time the whales arrive on the southern feeding grounds after the spring migration. There is thus a definite, if rather prolonged, breeding season. Risting (1928) discusses the results obtained from an examination of ninety-five Sei whale foetuses from the Norw'egian seas and finds that the majority of pairings took place from November to March,
. Discovery reports. Discovery (Ship); Scientific expeditions; Ocean; Antarctica; Falkland Islands. THE SEI WHALE 253 and April. Parturition and lactation appear to take place in temperate latitudes and lactation generally appears to be completed by the time the whales arrive on the southern feeding grounds after the spring migration. There is thus a definite, if rather prolonged, breeding season. Risting (1928) discusses the results obtained from an examination of ninety-five Sei whale foetuses from the Norw'egian seas and finds that the majority of pairings took place from November to March, that is during the northern winter, an exact parallel to the conclusion here arrived at about the southern Sei whale. Only three whales from South Georgia are recorded as lactating, all in the month of March, and they are all noted as only lactating slightly. These are presumably whales that paired late in the previous season and had given birth so late that lactation was not quite complete by the time that they arrived on the southern grounds. Similarly, the. Jan Feb Mar Apr Mai) Jun Jul Aug Sep Oct Nov Dec Fig. 78. Sei whale. Pairing and birth frequency. one carrying a 3-35 m. foetus, taken at South Africa in October, was probably a late breeder. These late breeders may be whales that have lost their calves and come into oestrus at abnormal times. With these whales may be compared three recorded as ovulating, two in February and one in March, which, if paired on the southern grounds, would produce such examples of late pregnancy in the following season. It is also of interest in this connexion to note that whale No. 2370, taken on 19 February 1929, was reported by the gunner to have paired immediately before capture. Further information on the breeding season is given by Fig. 78. If on Fig. 76 the curve in Fig. 77 is superimposed, and lines are drawn parallel to it but taking their origin at monthly intervals on each side of it, the points are divided up into groups represen
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