234 



G. PILLERI 



RÉSUMÉ 



Une observation unique de la copulation de Platanista gangetica est décrite. 

 L'observation a été faite en avril, dans un petit affluent du fleuve Brahmapoutra 

 (Assam), dans une eau profonde de 15 pieds. Le couple se dressa à demi hors de 

 l'eau, abdomen contre abdomen, avec les nageoires enlacées. Les individus se 

 maintinrent en position verticale par de violents mouvements de queue. Ils 

 retombèrent ensuite dans l'eau et se roulèrent ensemble sur leur axe, dans une 

 position inclinée par rapport à la surface de l'eau, pendant trois minutes. Les 

 révolutions axiales étaient effectuées de droite à gauche. 



Summary 



A single observation of the copulatory behaviour of Platanista gangetica is 

 described. This observation was made in April in a small tributary of the Brahma- 

 putra River (Assam) in a water depth of 15 ft. The pair rose out of the water with 

 their bellies touching and flippers enlaced. They maintained the vertical position 

 for several seconds by furious tail motion. They then fell back into the water and 

 rolled over together lying in a position approximately diagonal to the water-line 

 for a further two minutes. The rolls were executed from right to left round the 

 longitudinal body axis. 



LITERATUR 



Anderson, J. 1878. Anatomical and zoological researches : comprising an account of the 

 two expéditions to Western Yunnan in 1868 and 1875 ; and a monograph 

 of the two cetacean gênera Platanista and Orcella. B. Quaritch, London. 



Caldwell, D. K., M. C. Caldwell and D. W. Rice. 1966. Behavior of the sperm whale, 

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Pilleri, G. 1970a. Platanista gangetica, a dolphin that swims on its side. Rev. suisse Zool. 

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