Wl'KSlCKTAI,.: HKHAVIOKOK HOWUKAD WHALKS 



12 16 20 



TIME OF DAY (MDT) 



Figure 5. - Number of bowhead whale social interactions per aerial 

 observation hour in relation to time of day. 



curred during 53 of 133 (40%) surfacings with social- 

 izing, and in 128 of 484 (26%) without sociaHzing (x^ 

 = 9.04; df = 1,P< 0.005). 



When bowhead whales touched, they often appear- 

 ed to push each other. Pushing or touching was 

 usually done with the head, while oriented head to 

 head, or head to tail. However, we also saw whales of 

 adult size dive under the bellies of other whales and 

 apparently nudge or push the other whales near their 

 genital areas. At other times, whales dove under 

 each other at very close range without any indication 

 that they were touching. 



Apparent chase sequences involved two or three 

 whales in a line, usually < 2 body lengths apart. Dur- 

 ing these chases one whale often turned abruptly left 

 or right, and the second (and third) followed. Move- 

 ment was faster during chases than at all other times 

 when we saw presumably undisturbed whales at the 

 surface. 



Both touching and chasing may at times represent 

 low levels of sexual activity, but this is unproven 

 because we cannot determine the sex of a bowhead 

 whale from a distance. Payne and Dorsey (1983) and 

 Tyack and Whitehead (1983) described physically 

 interacting right and humpback whales, respectively, 

 which appeared to be engaging in social-sexual 

 activity. 



Possible Mating 



In 1981, we twice observed apparent mating. The 

 more prolonged observation was on 10 August 1981, 

 within a 25 km- area where there were 20-30 whales 

 whose main activity was socializing. Two whales 



interacted for over 1 h with chases, flipper caresses, 

 belly-to-belly orientation, rolls toward and away 

 from each other, head nudges to the genital area and 

 to the rest of the body, tail slaps, and flipper slaps. 

 One whale, a recognizable animal that we termed 

 "Whitespot", was about 1-2 m longer than the other 

 ("B") and was the more aggressive. Although B 

 originally nudged the genital area of Whitespot, it 

 was Whitespot who appeared to initiate flipper 

 caressing and rolls toward B. The two whales rolled 

 their ventral surfaces together for about 5 s, but B 

 then rolled its ventrum in the air in an apparent 

 attempt to avoid ventral contact with the larger 

 animal. As it rolled away from Whitespot, B 

 defecated, and when Whitespot moved its head 

 toward the genital area of B, B defecated two more 

 times in rapid succession. B then dove away from 

 Whitespot, and Whitespot followed it at the surface 

 in an apparent chase. Whitespot then stopped and, 

 alone at the surface, rolled two times and tail slapped 

 while on its back. It then dove, and the two appeared 

 together again at the surface 4 min later, with no fur- 

 ther energetic surface interaction. 



We do not know the sex of either animal, but it ap- 

 peared that Whitespot was attempting to copulate 

 with the reluctant animal. Some of us (Wiirsig and 

 Payne) have observed southern right whale females 

 frequently roll their ventra away from aggressive 

 males, leaving their genital areas above the surface 

 of the water, where the males cannot reach them. 

 Everitt and Krogman (1979) photographed very 

 similar behavior of a group of six bowheads off Bar- 

 row, AK, in May. Our observations here were highly 

 reminiscent of such behavior. Although adult 

 females are slightly larger than adult males in both 

 right and bowhead whales, we commonly see large 

 southern right whale males in pursuit of smaller 

 females, which attempt to avoid the males. 



On 25 August 1981, two bowheads briefly placed 

 their ventral surfaces together and clasped each 

 other with their flippers. After 1 min, they rolled 

 apart, blew, and dove slowly as a third whale ap- 

 proached. The mutual rolling and leisurely diving 

 indicated that, if this was copulatory behavior, it was 

 mutually undertaken by the two whales in contrast 

 to the previous example. 



Group Structure and Stability 



Two observations of recognizable bowheads pro- 

 vided evidence about group structure and stability. 

 We observed a distinctively marked pair of adults, 

 one accompanied by a calf, at about lat. 70°10'N, 

 long. 133°50'W on 7 August 1980. We saw a similar- 



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