NORRIS ET AL.: BEHAVIOR OF CALIFORNIA GRAY WHALE 



diameter. This broad abdomen narrowed im- 

 mediately to the tail which seemed to be of normal 

 diameter. In rapidly swimming animals the back 

 often seemed much less broad. Our supposition is 

 that in the passively floating animals the loose 

 articulation of the rib cage allows the buoyant 

 lungs to press the ribs outward, flattening the 

 floating animal. 



Feeding 



Uncertainty exists with regard to the amount of 

 feeding gray whales perform outside the Arctic 

 feeding ground and especially in or near the calv- 

 ing lagoons. Both Gilmore (1969) and Rice and 

 Wolman (1971) emphasized that nearly all 

 migratory whales that have been examined had 

 empty stomachs, while a few contained small 

 quantities of gastropod opercula, wood, 

 polychaetes, sand and gravel, ascidians, and 

 hydroids. Matthews (1932) reported observations 

 of gray whales feeding on shoals of Pleuroncodes 

 planiceps, an anomuran swimming crab, or "red 

 crab," off Magdalena Bay. Even so, Gilmore 

 (1969:15) stated "one authoritative opinion holds 

 that gray whales enter lagoons primarily to feed. 

 The whales allegedly plow the lagoon bottoms in 

 long furrows, exhausting first one section then 

 another of the rich beds of eel grass and inver- 

 tebrates. This opinion also asserts that the whale's 

 high, vertical thrust of its head out of water — long 

 considered a visual 'spy-hop' — is gravity swal- 

 lowing, necessitated by his non-protrusible 

 tongue." 



Our observation of a whale spying out with mud 

 cascading from the corners of his mouth at Colina 

 Coyote is difficult to interpret (Figure 5). Surely 

 the animal had grubbed in the bottom mud, but 

 this does not assure that feeding had occurred. 

 Nonetheless, at times we saw patches of muddy 

 water around whales that were diving and spying 

 out, indicating that much bottom grubbing was 

 not isolated and perhaps common. 



A more convincing observation was made by our 

 flight observation team of Thomas Dohl and John 

 Hall. They reported seeing 20 whales in shallow 

 greenish water 75-300 m off the beach between 

 Boca Animas and Boca Santa Domingo. Six of 

 these animals were travelling slowly leaving 

 muddy trails behind them. The trails were solid 

 spreading wakes of muddy water and some of them 

 were curved. They saw one whale surface and blow 

 while continuing to trail such a wake, probably 



indicating that muddy water was issuing from its 

 mouth. Their strong impression was of whales 

 grubbing in the bottom producing the trails as 

 they swam along. Once again we cannot be sure 

 that these animals were feeding, but it is fair to 

 say that probably with reasonable frequency 

 whales in or near calving lagoons grub in the bot- 

 tom mud or sand and take at least some of it into 

 their mouths. Perhaps it is "pseudo feeding" as 

 Gilmore (1969) suggested, but it is also possible 

 that limited feeding does occur in or near the 

 calving lagoons. 



Population Segregation 



We can confirm the long standing observation 

 (Gilmore 1961) that at lagoons population 

 segregation of a marked sort takes place. Mother 

 whales with newborn young are indeed confined 

 largely to inland waters within the lagoon sys- 

 tems. Single animals are rather uncommon there. 

 Aggregations of whales without calves are com- 

 mon at or near entrances and in the nearby 

 offshore waters. A considerable percentage of 

 these animals is found in groups of two to six 

 animals and much rolling, fluking, throwing of the 

 pectorals, and bodily contact can be seen. Occa- 

 sionally a protruded penis was noted as a whale 

 rolled on its back and more often the perineal 

 sheath of the male could be seen in such cir- 

 cumstances. Groups at bay mouths typically 

 contained many moderate size animals, which we 

 estimated at 10-12 m long. It seems probable that 

 both yearling, juvenile, or young adults of both 

 sexes and older males were involved. 



All whales found south of the southernmost 

 calving lagoon at Almejas Bay seem to represent 

 this mixed group of males, yearlings, or non- 

 parturient animals. The large group of animals 

 seen around Cabo Falso and Cape San Lucas was 

 of this type with no small young of the year being 

 noted. 



Aggressive Behavior 



Gray whale aggression has been the subject of 

 some controversy. Hand whalers reported ag- 

 gression toward whale boats from animals har- 

 pooned in the lagoons (Scammon 1874). Later, 

 some research workers have had boats damaged in 

 encounters with whales. Nonetheless, suspicions 

 existed that these encounters were due to the 

 thrashings of a very large innocuous beast in 



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