THE SOUTHERN SEA LION i S3 



One cannot be certain that this cow was delivered at full time, since there is always 

 the possibility of abortion, and although it must be assumed that this is rare in wild 

 animals, a marine mammal such as the sea lion is exposed to a possibility of violence from 

 the sea from which land animals are immune. Three seals killed in September and two 

 killed in November showed by the great size and the condition of the uterus that they 

 had been pregnant recently, although no pups were seen in the neighbourhood of these 

 cows. It scarcely seems reasonable to attribute all these, so near the breeding season, 

 to abortion: traces of milk were found in one cow, no. 530, which strongly suggests that 

 this animal had come to full time and, further, a newly ruptured follicle was found in a 

 non-pregnant seal killed on 15 November, thus at least implying the possibility of a 

 fertilization which might produce a birth prior to the regular pupping season. 



The death rate is exceptionally high among the earliest pups. In three seasons 

 29 pups were seen on or before 16 December and of them 11 had died shortly after 

 birth. It is my opinion that the five cows mentioned above had given birth in the normal 

 way and had lost their pups. On p. 307 of my previous report comment was made on 

 the frequency of deaths of pups born of isolated cows outside the rookeries. The factors 

 suggested there will apply with still greater force to pups born before the breeding 

 season has begun, since there is then no organization of rookeries and harems to which 

 the cows can be attached, and in the period just before the breeding season the bulls are 

 very ferocious and there is a tendency for the cows to be frightened away by the combats. 



Coitus continues until the last days of January, having been observed on the 29th and 

 30th and even so late as 3 February. Sperms were seen in sections of the uteri of the 

 following cows killed outside the period of observed coitus: nos. 477, 530, 512, 475, 

 492 and 424. The spermatozoa occur in the uterine glands in nos. 530, 492 and 424 but, 

 as is well known, sperms can survive in a recognizable, although rather "fossilized", 

 condition for long periods (Deanesley, 1935), so that these cannot be regarded as 

 conclusive evidence that coitus has taken place even comparatively recently. In no. 512, 

 9 July, there are sperms actually in the lumen of the uterus and in an apparently fresh 

 state, but they are most numerous in the openings of the glands. This seal therefore had 

 been covered at a more relatively recent time than the three mentioned above. No. 475, 

 killed on 16 September, and no. 477, 28 November, both had sperms in the lumen, 

 the former many and the latter rather few: it is impossible to avoid the conclusion that 

 both these seals had enjoyed coitus quite recently. No. 477 fits in with what is known 

 of the breeding season in general, and the presence of sperms in a cow killed in September 

 may be correlated with the occurrence of recent post-partum animals such as those 

 which have been discussed above. No. 512 is in a different category; this animal was 

 collected at a time which is known to be about six months distant from the height of the 

 breeding season and the finding of sperms in the lumen of a uterus is an indication of 

 tolerably recent copulation. It has already been stated that from July onwards bulls have 

 been seen paying attention to cows, and from this it is reasonable to conclude that there 

 is occasional coitus, but it should be assumed that it is infertile unless indeed no. 1001 

 was delivered of a full-time pup. It is certain that if pups are born in winter they are 



