58 



G. PILLER! 



INTRODUCTION 



The Amazon dolphin (Inia geoffrensis de Blainville 1817), known locally as 

 the " buffeo ", is a member of the order Cetecea found only in the rivers of tropical 

 South America. It belongs to the Susuidae family (see Hershkovitz 1966). 

 Belonging to the same family are the La Plata dolphin (Pantopoha blainvillei 

 Gervais and d'Orbigny 1844) found at the mouths of rivers, the Ganges dolphin 

 {Susu gangetica Lebeck 1801) found in the Ganges, the Indus (although it seems 

 to be exterminated here, Taber, Sheri, Ahmad 1967) and the Brahmaputra 

 (Anderson 1878, Pilleri 1966, 1968) and the Chinese river dolphin (Lipotes 

 vexillifer Miller 1918) found evidently only in the Tung-Ting lake. Another fresh 

 water dolphin, the Irrawaddy dolphin (Orcella brevirostris Gray 1871) is found in 

 rivers as well as in the open sea (Anderson 1871, Hershkovitz 1966). The 

 " tucuxi " (Sotalia flmiaiilis Gervais and Deville, in Gervais 1853, see Williams 

 1931) is a fresh water dolphin often found together with the Inia. Other species 

 of Sotalia (guianensis, brasiliensis, chinensis, bomeensis, lentiginosa, plumbea and 

 îeuszi) are found in warm sea waters at the mouths of rivers. Apart from articles 

 of a more popular nature, often containing much misinformation, there are very 

 few scientific publications on the behaviour of the Amazon dolphin. The most 

 complète observations were made by Layne (1958) and Layne and Caldwell 

 (1964). Recently American zoologists have been able to catch the animal alive 

 in rivers in Peru and have transported by air several dolphins to aquariums in the 

 United States. Layne was therefore able to make observations, not only in the 

 field, but also on animais in captivity (Florida). There are now dolphins in captivity 

 in the Steinhart Aquarium in San Francisco, in the Marineland of the Pacific 

 (Los Angeles) and in the Fort Worth Zoo (Texas). 



During my last expédition (1968) in tropical Bolivia (Beni district), I was able 

 to observe and photograph wild buffeos. Four dolphins were caught for the purpose 

 of anatomical investigation. Because little is known of this interesting cetecean 

 species and because of the lack of photographie documentation, 1 have attempted 

 to fill in some of the blank spaces with the following observations. 



I am very grateful to my colleague Dr. med. Hans Gruenberger, La Paz, the 

 médical student Arthur Zimmermann, Bern who accompanied me on my trip to 

 Bolivia, and the mayor of Trinidad, Hernân Dorado Claros, for their generous 

 help in South America. Miss Mirella Antonelli, laboratory assistant in the Brain 

 Anatomy Institute Bern enlarged and ordered ail of the photographie material 

 for which I am grateful. Miss Janet Knuckey was responsible for the translation 

 of the script. 



