Unusual lipids II: Head oil of the north Atlantic pilot whale,Globicephala melaena melaena

Pilot whale head oil (blackfish head oil, raw) was analyzed by means of IR spectroscopy, NMR, thin layer chromatography, and gas liquid chromatography-mass spectrometry. The oil consisted of hydrocarbons (mainly pristane) (3%); waxes and cholesterol esters (9%); triglycerides (87%) (i.e. non-11%, mono-19% and di-57% isovalero triglycerides) and cholesterol and diglycerides (1%). By mass spectrometry, the diisovalero triglycerides were shown to be mainly symmetrical. Fatty acids were isobranched or normal (only traces of anteiso acids were found), saturated, or monounsaturated. Isovaleric acid predominated (54 mole % fatty acids), the rest having 10–18 carbon atoms. A 5-carbon fatty acid was the only acid found in the waxes. The alcohol composition qualitatively resembled that of the fatty acids, but major quantitative differences were present. This rules out direct interconversion of all fatty acids and alcohols. The possible role of these lipids in ultrasound transmission is discussed.