NORRIS ET AL : BEHAVIOR OF CALIFORNIA GRAY WHALE 



cycle regardless of tide. Probably such behavior is 

 an important means of avoiding stranding in the 

 complicated shallower channels of calving la- 

 goons. 



Whales seldom leave the fairly deep channels, 

 even at the highest tides. Much travel occurs along 

 the channel edges but the animals seldom venture 

 over tidal flats or sand bars, even those covered 

 with 2 or 3 m of water. Occasionally, whales will 

 venture over the edges of such flats when avoiding 

 other whales or a pursuing vessel. The usual 

 reaction to pursuit, however, is to seek deep water. 

 An exception was produced by what we suppose 

 were the pursuits of female whales by males. 

 These chases, often involving three animals, 

 sometimes went into water so shallow that the 

 whales were nearly stranded. Very narrow 

 channels are, however, avoided; we seldom saw 

 whales traverse areas narrower than 130-140 m in 

 width. Because the channel south of Colina Coyote 

 in Devil's Bend is both narrow and sinuous and 

 because we never saw whales there, we suspect it 

 is not used and thus whales in Magdalena Bay are 

 a separate group from those off Colina Coyote that 

 use the Boca Soledad entrance to the sea. 



Aerial Behavior 



A controversy has long existed over the func- 

 tions of the various kinds of aerial behavior 

 exhibited by the gray whale (see, for example, 

 Gilmore 1961, 1969; Walker 1962). 



In our observations breaching is very different 

 behavior from the much more leisurely spying out 

 behavior (see also Walker 1962), and the two occur 

 in quite different contexts. We use the term 

 breaching to indicate a partial leap, often until 

 two-thirds or more of the animal is free of the 

 water, usually terminating with a rolling turn 

 that causes the animal to reenter backward or on 

 its side with a large splash that can often be seen 

 for several miles. Breaches usually occur in 

 sequences, often of three, and usually with de- 

 creasing vigor through the sequence. Gilmore 

 (1961) reported seeing 11 breaches in a single 

 sequence. A breach is vigorous, even violent 

 behavior. We have watched many breaches and 

 cannot report any being made by a cow with a calf, 

 though Gilmore (1961) reported that mothers and 

 calves sometimes breach. Instead, they seem to be 

 made predominantly by rapidly moving animals 

 that may be males or females in the company of 

 males. It seems possible to us that such leaps 



represent sexually related displays, perhaps not 

 unlike the breaches of such forms as humpback 

 and male killer whales. 



We have seen breaching most commonly at sea 

 or in the seaward parts of lagoons where mating 

 was common, although it was seen on three 

 separate occasions in the deepest part of the Boca 

 Soledad in front of Colina Coyote. On these oc- 

 casions, it was performed by a swift-swimming 

 unaccompanied animal that entered and caused 

 some chases and agitation among the otherwise 

 placid mother-calf pairs. Because of this creation 

 of agitation among the nursing females, and 

 because of its relatively small size, we suspect that 

 it was a male. 



In sharp contrast, a spy out is a leisurely event 

 in which the animal raises its head slowly out of 

 the water, often nearly to or slightly beyond the 

 level of the eyes, and then slips back into the water 

 as gravity causes it to fall slowly out of 

 equilibrium. In shallow water, we believe spy outs 

 are performed by an animal with its tail pressed 

 against the bottom, and that flexing of the back 

 forces the head out. Cows with calves often spy out, 

 though single animals also exhibit the behavior. 

 At Colina Coyote, spying out most often occurred 

 in a rather tightly circumscribed sector at the edge 

 of the channel from the middle of Isla Pierce north 

 past Cabo Forment, Canal Segundo, and Isla 

 Central, though it was seen occasionally in the 

 middle of Canal Central (Figure 4). Soundings in 

 this area showed a rather uniform depth of 8 to 

 10 m. 



The eyes of the animals spying out were often 

 below the waterline, and hence aerial vision was 

 not always involved. Further, spying out was 

 observed at night off Cabo Forment by use of a 

 night vision scope. The observation occurred on a 

 clear moonlit night. It is our strong impression 

 that this kind of spy out is not related to viewing 

 surrounding terrain or objects in air but is usually 

 performed by nearly quiescent animals that may 

 simply be making comfort or postural movements. 

 We could not determine if it had any relation to 

 nursing though we did see calves circling spying 

 adults which suggests that nursing was not 

 necessarily involved since the teats of the mothers 

 were at least 6 m below the surface. The reverse 

 behavior was occasionally seen, especially in 

 Bahia Grande, in which an animal extended its 

 tail into the air for a few seconds before subsiding 

 back into the water, as if its snout was resting in 

 the bottom mud. 



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