GULF OF MEXICO 



549 



henny has reported finding dolphins with a 

 bucketful of freshly eaten shrimp in their stomachs. 

 Kleinenberg (1938) reported finding one shrimp 

 among thousands of fishes in the stomach of this 

 dolphin in the Black Sea. The bottlenose dolphin 

 causes considerable trouble to the shrimp fisher- 

 men because it tears holes in their trawls in 

 eflforts to get at the fish and shrimp within. 

 They report that the animal can distinguish 

 change in the engine beat when the trawl is low- 

 ered and will come from long distances to where 

 a drag is being made. 



Wislocki and Enders (1941) have shown that 

 the embryos are carried in the left uterine cornu. 

 Gunter (1942) has shown that the length of dol- 

 phins at birth is 44 inches and more. Several 

 stillbirths and some successful ones have been 

 observed by McBride and Kritzler. In all cases 

 the young were bom tail first. The mother does 

 not bite the umbilical cord in two but whirls in a 

 characteristic fashion and breaks it. The baby 

 makes its way unaided to the surface at once and 

 begins to breathe. In cases of stillbirth, how- 

 ever, the mother tries to lift the young, sometimes 

 being aided by other females. Moore (1953) found 

 a female in the wild holding her decayed young 

 to the surface. He judged the baby had been 

 dead at least 3 days. The babies post them- 

 selves a little above and behind the dorsal fin of 

 the mother. Other females apparently try to 

 help the mother in protecting the young and often 

 the little dolphin swims between the mother and 

 another female. From the time of birth they 

 can swim fast enough to keep up with adidts 

 swimming at a fairly high rate of speed. When a 

 baby is temporarily lost from its mother, it swims 

 in a tight circle and whistles until she comes. 

 The preceding information is taken from McBride 

 and Kritzler (1951). 



Dolphins can be overtaken with outboard motor- 

 boats at a speed of 22 miles per hour. The maxi- 

 mum speed of 60 miles per hour often popularly 

 accredited to these animals is a preposterous 

 overestimate. 



Male porpoises fight viciously during breeding 

 periods and acquire many scars from these battles. 

 They are sometimes seen milling about in water 

 tinged with their blood. Gunter (op. cit.) found 

 that the size of the fetuses increased from Decem- 

 ber to April, and the first young were taken in 



April. On the other hand, McBride and Kritzler 

 (op. cit.) think that there is no special breeding 

 season. They say that the calves are nursed for 

 18 months and that the females in captivity do 

 not reproduce more than once every 2 years. 



The bottlenose dolphin seems to rank rather 

 high in the intellectual scale of the mammals. 

 In captivity the young have been observed to 

 invent little games which are played alone or with 

 the help of a human partner. Interested readers 

 should consult McBride and Kritzler (op. cit.) 

 and papers cited therein. 



The numbers of these dolphins are not exten- 

 sive enough for any commercial enterprise to be 

 centered on them, although their flesh is good 

 food. They have not been the cause for declines 

 of fishes as is sometimes stated. They were 

 present in much greater numbers years ago, 

 when apparently all life in the shallow bays was 

 also more abundant, and they seem to have 

 declined in numbers during the past 50 years. 

 Writers of years ago reported that the bays of the 

 Gulf coast formerly teemed with these dolphins. 

 Now they are numerous only in the passes lead- 

 ing from the bays to the Gulf. 



Grampus orca Linnaeus. Atlantic Killer Whale 



This species is widely distributed in the seas of 

 the world. There is a different species in the 

 North Pacific. As Kellogg (1940) said, they fear 

 nothing that lives. They usually travel in packs 

 and ferociously attack all other marine mammals 

 including the larger whales. They grow to a 

 length of 22 feet or more and have capacious 

 gullets which enable them to swallow seals and 

 the smaller porpoises whole. Their diet is varied 

 by larger fishes. 



The high dorsal fin and conspicuous white spots 

 back of the eye and under and behind the dorsal, 

 and the white belly are identifying marks. The 

 latter area extends up on the side posteriorly. 



Moore (1953) has given several records from 

 the Atlantic side of south Florida. There are no 

 records from the Gulf, based on actual specimens, 

 but they are to be expected, and one was sighted 

 35 miles southeast of Port Aransas, Texas, in the 

 summer of 1951 by Capt. R. C. Van Zandt, who is 

 well acquainted with the Pacific species and its 

 depredations on the west coast of Mexico. 



