320 UNDERWATER GUIDE TO MARINE LIFE 



of swift, jolting blows. Sometimes several dolphins maneuver the shark into 

 position so that another can strike a fatal blow in a tender spot like the region 

 of the gills. Dolphins are also known to have pushed drowning people ashore, 

 though stories of this sort are even more difficult to run down. The recognition 

 of a person in distress would take a very high degree of intelligence; the pushing 

 which we interpret as a rescue probably arises from the tendency of dolphins 

 to push or nudge surface objects. For instance, they are known to give newborn 

 young a push toward the surface to necessary air. 



Most of what is known of dolphins is drawn from their behavior in captivity. 

 There, these swift and extraordinarily playful creatures with the built-in grin are 

 a constant source of amusement, taking well to captivity and their captors. 

 Excepting the primates, their intelligence is perhaps greater than that of any 

 other animal. Their brain is convoluted and a little heavier than man's. The 

 highly developed brain of dolphins accounts for their elaborate play. For example, 

 one poor pelican at Marineland in Florida was the object of frequent torment. 

 One dolphin would pluck a feather from it, which it would toss about or try 

 to balance on its nose as it swam. At other times, the bird would be the recipient 

 of rather violent spanks from below, to its great consternation. Dolphins 

 constantly nipped at the fishes in the tank and used to annoy a turtle by turning 

 it repeatedly on its edge (Williams, 1950). The dolphin's plav with people in 

 the tank was well intentioned, but it tended to be a bit rough at times. Dolphins 

 like to play catch. They will retrieve all sorts of objects, overshadowing retrieving 

 dogs by throwing the object back. One dolphin, having received a somewhat 

 overly dead mullet for food, threw it back, hitting an innocent lady bystander 

 in the face. 



Dolphins live for forty years or a little more. Much of their time is occupied 

 with sex play, the ever-eager males seeming never to tire of chasing the females. 

 The females in return, in heat only a few times a year, never seem to tire of 

 eluding the males. The males form a hierarchy and fight among themselves for 

 the female's attention. McBride and Hebb (1948) record several examples of the 

 male's sexual ardor, one of which deserves mention. The penis "forms an efficient 

 hook, and a young male was seen on several occasions to swim down at consider- 

 able speed, scoop up an eel at the bottom of the tank, and swim zig-zag all the 

 way across the bottom of the tank with the eel wrapped about [it]." 



When a female is giving birth, the normal companionship which dolphins 

 show toward each other is accentuated. At such times, thev band together and 

 are alert, for the blood occuring at birth attracts sharks, which are driven away 

 by these attendants. 



Dolphins are truly masters of the seas, able to elude all pursuers except a 

 member of their own family, the killer whale. Swimmers will have fascinating 

 experiences with them under water and should carefully record what they see 

 because little is known of them out of captivity. Dolphins will not usually flee 

 a swimmer; in fact, they will often nudge a swimmer playfully. 



COMMON dolphin: Delfhinns delfhis 



Size: Up to 8 feet or more. 



Distribution: Cosmopolitan in warm temperate and tropical seas, chiefly 

 offshore. 



