Jaw oil: the precision lubricant taken from dolphins and porpoises

The whaling trade did not speak of “whale oil” in the singular. It distinguished three products at very different prices: the train oil of baleen whales, the sperm oil of the sperm whale, and melon oil, the head and jaw oil of the small odontocetes. The last was the dearest per litre, and it drove a hunt of its own.

An oil that is not a fat

Dolphins, porpoises and the other odontocetes carry a melon in the forehead, and in the lower jaw elongated fatty bodies that conduct sound towards the inner ear. These tissues do not serve as an energy reserve: they are acoustic lenses, whose composition sets the speed at which sound travels through them.

That function calls for a particular chemistry. The melon and the jaw oil are dominated by wax esters and by short, branched fatty acids, isovaleric acid in particular, rather than by the ordinary triglycerides of blubber.

The result, for a nineteenth-century mechanic, verged on the miraculous: an oil that does not congeal in the cold, does not thicken, barely oxidises, leaves no gummy deposit and clings to metal.

The watchmakers’ oil

A precision watch or a marine chronometer owes its accuracy to constant friction. An oil that thickens at five degrees and thins at thirty throws the instrument off, and an oil that oxidises seizes it up after a few years.

Porpoise or dolphin jaw oil solved this problem better than any other lubricant available. It is found in watchmaking, in the marine chronometers on which the calculation of longitude depended, in scientific instruments, in weapon mechanisms, and in typewriters and sewing machines.

Sold in small quantities at prices unrelated to those of the barrel of industrial oil, it sustained a specialised fishery, directed not at the large rorquals but at animals of two to five metres.

Pressure on coastal species

This is what sets this product apart from all the others in this dossier, and what makes it important.

The hunt for the large rorquals took place offshore, in the Antarctic, thousands of nautical miles from the coast. The hunt for the small odontocetes was carried on close to the shore, on local populations, often resident and few in number, and by means that required neither a factory ship nor a harpoon gun.

This kind of take can exhaust a population without the national statistics recording much, because the catches are scattered and poorly declared. It is one of the blind spots of the whaling statistics, which were built around the large species.

The same species face other pressures today, in particular bycatch in fishing gear.

What replaced it

The same substitutes as for spermaceti, whose chemistry is close by: jojoba oil, whose seeds naturally produce wax esters, and synthetic esters formulated to order.

Modern watchmaking uses synthetic oils whose thermal stability now exceeds that of the animal oil. The product therefore left the market through technical obsolescence, and international trade in cetacean products is prohibited by CITES in any case.

This page is part of our dossier on whale products.