Distinctive medium chain wax esters, triglycerides, and diacyl glyceryl ethers in the head fats of the Pacific beaked whale, Berardius bairdi.

Lipids were extracted from the mandibular fat body (jaw), the fatty forehead (melon), and the dorsal blubber of a Pacific beaked whale (Berardius bairdi) and separated into lipid classes by preparative thin layer chromatogrphy. The head fats were mixtures of wax esters and triglycerides with a very small amount of diacyl glyceryl ether. The blubber fat contained 97% wax ester and 3% triglyceride. Gas liquid chromatography (GLC) of the intac lipid classes indicated an unusually low C26-C30 range for most of the jaw and melon wax esters compared to the more normal C32-C40 molecules found in the blubber. Distinctive lower molecular weight C24-C40 triglycerides occurred in the head fats vs. the usual C44-C58 range in the blubber. Most diacyl glyceryl ethers were in the C35-C46 range, below the molecular weight of hexadecyldipalmitoyl glyceryl ether (C48). GLC of the derived fatty acid methyl esters showed that the lower molecular weight neutral lipids in the head fats were due to high levels of iso-10:0, n-10:0, iso-11:0, iso-12:0, N-12:0, and iso-13:0 acids. The wax ester fatty alcohols and the alkoxy chains of the glyceryl ethers were mostly the C14-C20 chain lengths commonly observed in marine organisms. The distinctive medium chain neutral lipids in the jaw and melon fats of this whale may be related to the postulated acoustical role of these tissues in echolocation.