RESPIRATION I27 



that on crossing the equator on 7th July, 1955, at 130" E, he observed a 

 Sperm Whale peacefully swimming at the surface and blowing every 

 two or three minutes. Clearly, after a deep dive, breathing may increase to 

 up to fifteen times the normal rate. 



Basing our case on what few data we have, we may say that, by and 

 large, three types of respiration can be distinguished in Cetaceans, based 

 on the length of their respective dives. The first group includes such deep- 

 sea divers as Sperm Whales and Bottlenose Whales, which have been 

 reliably reported to be capable of staying under for as much as 90 and 

 120 minutes respectively. But then, these are record performances. 

 Normally, the animals dive for 50 minutes, and then stay at the surface 

 roughly 10 minutes to take about six breaths per minute before they dive 

 down again (Fig. 74). It is quite possible that Cuvier's Dolphin, which is 

 very closely related to the Bottlenose Whale, belongs to this same group, 

 but what data we have on it require further checking. 



Right \Vhales and Rorquals represent the second type of respiration. 

 The Greenland Whale is reported to stay submerged for up to 60 minutes, 

 and Rorquals for up to about 40 minutes. Clark cites the case of a Fin 

 \Vhale that became enmeshed in a drag-net cable off Cape Cod on 8th 

 April, 1958. The animal struggled furiously to get out but died after 

 30 minutes. Had it not been fighting for its life, it would probably have 

 l)een able to stay submerged for at least another 10 minutes. Animals in 

 this second group usually remain underwater for 10-15 minutes, coming 

 up for 5-10 minutes at a time. At the surface they take about 5-20 breaths, 

 with an average of one breath per minute. Frequently, however, they dive 

 for only 4-7 minutes, the difference in time depending on their agility or 

 possibly on their method of feeding. Chittleborough (1956) noted that 

 Southern Right Whales dive for 2-3 minutes and then come up for 8-q 

 minutes, blowing 6-9 times during that period. If Fin Whales are chased 

 by a catcher, they may come up every 70 seconds. This may be called 

 panting (van Utrecht). 



The third group is made up of dolphins and porpoises which do not 

 descend to very great depths. They usually dive for up to about 5 minutes, 

 and svu'face to blow up to six times per minute. However, when they swim 

 near the surface, they can manage with only two breaths per minute. 

 Kleinenberg (1956) noted that Common Dolphins in the Black Sea dive 

 for ii-3 minutes,^ porpoises from 4-6 minutes and Bottlenose Dolphins 

 (which find their food in lower regions of the sea) for 13-15 minutes. A 

 1 5-minute dive by Belugas was noted by Vladykov. 



If we compare these figures with those for other mammals, we discover 



^According to Tomilin (1948), these animals die when their breathing is impeded for 

 more than 5 minutes. 



