Some Aspects of the Biology of Peponocephala Electra (Cetacea: Delphinidae) I. General and Reproductive Biology

The very limited literature concerning the biology of P. electra is reviewed briefly, and a stranding of 53 individuals on Moreton Island, south-eastern Queensland, in August 1976 is described. A description of schools of animals observed at sea is given. Limited observations of body dimensions, growth, and relationship of body length and weight are reported. The anatomy of the reproductive tract of three female melon-headed whales is described, including detailed descriptions of the ovaries, and the histological appearance of the testes of four males is summarized. Tentative conclusions from available data are: sexual maturity in females is reached at a body length greater than 225 cm but probably considerably less than 257 cm, and after four laminations, but before 12 laminations are deposited in the dentine. Sexual activity in males seems to develop at a length of 260 cm, when approximately seven tooth laminations are present. Birth occurs from August to December in the southern hemisphere, and the gestation period is probably approximately 1 year