PERRIN and HUNTER: ESCAPE BEHAVIOR OF PORPOISE 



WESTWARD 



MOANA 



55m WIDE: DEPTH VARIED 



N v\// 



fAILEO ,T9 ESCAPE, 



5.5m WIDE; DEPTH VARIED 





n DEEP :a6lmOEEP : l.lm DEEP | Q30m DEEP 

 55m WIDE, DEPTH VARIED 



■t] 



r\ 



< 5 10 IS 20 25 30 35 



TRIAL NUMBER 



15 20 25 30 35 40 



J^\ 



r 



3.1m WIDE I iSm WIDE ; 1.5m WIDE ; 55m WIDE 



1 DEEP, WIDTH VARIED 



V^l 



ESCAPE 



OVEB 



PANEL 



DEPTH VARIED 



10 15 20 25 30 35 



TRIAL NUMBER 



Figure 5. — Results of experiments with naive porpoise 

 Westward. I. June 12, II. June 22, III. June 24, IV. 

 June 25, V. June 26, VI. June 29, 1970. 



the other hand, remained at the surface in a 

 near-upright position with blowhole exposed and 

 rostrum submerged, swimming very slowly with 

 slow, low-amplitude beats of the posterior half 

 of the body. Her head bobbed up and down 

 slightly as she swam. Opinion among the ani- 

 mal-training staff of the Oceanic Institute as 

 to the cause of this behavior was divided; some 

 believed the animal to be in shock, perhaps even 

 moribund, others believed the behavior to indi- 

 cate extreme fright. The first experiment was 



5.5m WIDE. DEPTH VARIED 



V/ 



,f^m DEEP 



O FAILED TO ESCAPE 



A/ 1 



1 DEEP I OGim DEEP ; I Im DEEP 

 55m WIDE; DEPTH VARIED 



DEPTH VARIE, 



OI5m DEEP 



,V^ 



O TO ESCAPE 



/55m WiDf 



Urn DEEP, 

 WIDTH VARIED 



: &5m WiOE 



I DEEP; WIDTH VARIED 



FAILED TO ESCAPE O 



20 25 50 35 



TRIAL NUMBER 



Figure 6. — Results of experiments with naive porpoise 

 Moana. I. July 10, II. July 11, III. July 12, IV. July 13, 

 V. July 15, 1970. 



carried out the day after capture. Subsequently 

 Westward's behavior slowly changed, until 5 

 days later on June 17 it was indistinguishable 

 from that of the trained porpoise. The re- 

 mainder of the Westward experiments were car- 

 ried out after June 17. 



Moana, the second naive porpoise, was cap- 

 tured on July 9, 1970. When placed in Bateson's 

 Bay, she exhibited the same behavior as West- 

 ward, but to a lesser extent. Periods of surface 

 swimming in a semiupright position, but without 

 head-bobbing, were interspersed with periods of 

 normal porpoising and diving. During the first 

 experiment she swam slowly at the surface in 

 the diagonal posture but during the second and 

 subsequent experiments, her behavior was sim- 

 ilar to that of the trained animals. 



55 



