MAMMALS 



{Cetacei) 



While voyaging v/e were often encircled by shoals of playful 

 dolphins [Delphinus delphis) . The same cetaceans are met with 

 in great numbers near the islands along the barriers. 



Our mxeting with another member of the group has 

 already been described by Roghi. I am referring to the pilot 

 whales {Globicephala meloena). We found ourselves tete-a-tete 

 underwater with these intelligent creatures, and our recip- 

 rocal curiosity brought us face to face, more than once, at 

 a few yards distance. We were impressed most of all by the 

 continuous whistle or chirp which these giants emitted. This 

 can only be interpreted as a signal warning or a means of 

 communication between them. Naturally I do not want to 

 give greater importance to the phenomenon than it deserves, 

 but I would exclude the explanation that it is caused simply 

 by a passage of air from the blowhole. I believe that it is 

 more probably a real sound deliberately created by the 

 animal. 



Bigger cetaceans, the sperm-whales {Physeter catoden) may 

 sometimes be encountered, but these usually keep to the 

 southern area. In certain seasons of the year they follow the 

 big shoals of fish which cross the straits of Bab el Mandeb 

 entering the Red Sea from the Indian Ocean. We met four 

 of these monsters at the level of the island of Curunsas, in 

 Dankalia, in May. They were in the coastal shallows, wildly 

 chasing legions of bonitos, tunny and mackerel which were 

 in turn following swarms of sardines. 



1280 



