N OTE

A Noninjurious Attack by a Small Shark!

DAVID P. FELLOWS and A. EARL MURCHISON2

ASIDE FROM the general need for thorough side to side in a greatly exaggerated swimming documentation of shark incidents (Hobson, motion. The headswinging was sufficient to et al., 1961 :605) , the following shark attack bring the entire head profile into view by is worthy of report for two reasons : (1) The Fellows, who at this time was directly behind shark was of small size. ( 2) Immediately and about 5 ft away from the shark. This be­ prior to attack the shark displayed a behavior havior was continued for slightly less than half pattern which is menti oned only briefly in the a lap, at which time Fellows surfaced for air. literature. When Fellows surfaced, the shark , swimming over a coral mound, rose to within approxi­ Description of the Incident mately 6 ft of the surface, passed directly below The shark, a 3-ft Carcbarbinns menisorrab, Murchison, and descended back to within 5 ft was encountered while the authors were baiting of the bottom. As the shark approached eel traps with freshly speared fish in a large Murchison during its ascent, the exaggerated pothole in the lagoon at Johnston Island. swimming motion stopped. Immediately after At the time (1 400 hours, 19 December 1965) , passing under Murchison the shark began to water was 26° C and underwater swim more rapidly, resumed the exaggerated visibility more than 100 ft. The weather was manner of swimming, and, when 25 ft away, cloudy with intermittent rain, a strong wind was turned and made a very rapid dash directed at blowing, and the surface of the sea was choppy. Fellows's arm. D uring the approach the shark's Both divers were wearing dark trunks and black mouth was open approximately 1 inch. Fellows neoprene jackets. twisted violently aside, and the shark missed The attack occurred during an attempt to his arm and passed between his legs. When take the shark by spear for research purposes. five ft behind Fellows, the shark turned and Armed with a "Hawaiian sling," Fellows closed made a second high-speed pass. On this pass to within 7-8 ft of the shark and then began 's swim fin made solid contact with the to follow the shark as it swam slowly in a path shark, but whether contact was due to Fellows's roughly describing a circle about 50 ft in thrashing or to directed attack by the shark is diameter. During the first lap of the chase, the uncertain. Either way, contact was sufficient to shark swam in an unexcited manner approxi­ discourage the shark, which rapidly departed mately 5 ft above the bottom of the pothole from the area. During the two passes the divers (which was about 15-25 ft deep ) . Immediately were about 7 ft apart. after beginn ing the second lap, the shark com­ menced a radically different swimm ing behavior; Discussion the tailbeat frequency decreased noticeably and Although the total time of the encounter with the shark simultaneously began to swing the the shark occupied less than 3 minutes , and the entire anterior portion of the body slowly from duration of the actual attack less than 10 sec­ onds, both observers readily noted four items: ! Contribution N o. 257, H awaii Institute of Marine (1) At the beginning of the chase the shark Biology,Universi ty of H awaii. Manuscript received February 14, 1966. showed no overt response to the divers' pres­ 2 Dep artment of Zoology, Un iversity of H awaii, ence. ( 2) The headswinging behavior began H onolulu. only after the pursuer got within what appeared 150 Shark Attack-FELLOWS and MURCHISON 151 to be a critical distance. ( 3) H eadswinging be­ signal an intention of attack on the part of a havior immediately preceded attack behavior. harassed shark . (4) H eadswinging behavior appeared only It is the opinion of the authors that the inci­ when the diver was behind the shark. dent reported here was a defensive behavior The same exaggerated swimming motion has by the shark, provoked by pursuit in a confined been reported by Hobson ( 1961 :29) as occur­ area. ring in at least two species of Carcbarbinus. In one case the behavior immediately prefaced REFERENCES an attack on a diver at W ake Island. The present H OBSON, E. S. 1961. Sharks increasing visual authors agree with Hobson's opinion that the field. Underwater N aturalist 2: 29. behavior permits the maintaining of visual con­ ---- F. MAUTIN, and E. S. REESE. 1961. tact with an object directly behind the shark, Two shark incidents at Eniwetok Atoll, but they also suggest that the behavior might Marshall Islands. Pacific Sci. 15 :605-609.