From Wikipedia
Mink oil is a source of palmitoleic acid, which possesses physical properties similar to human sebum. Because of this, mink oil is used in several medical and cosmetic products. Mink oil is also used for treating, conditioning and preserving nearly all kinds of leather.
Botanical alternatives to mink oil as a source of palmitoleic acid include macadamia nut oil (Macadamia integrifolia) and sea buckthorn oil (Hippophae rhamnoides), both of which contain as much or more palmitoleic acid (17% and 19–29% respectively) than does mink oil (17%).[1][2]
"Mink oil and its fatty acids are unique among animal-derived fats and oils. The total unsaturated fatty acids in mink oil account for more than 75% of the fatty acid content, but the oil, nevertheless, has a greater oxidative stability (resistance to rancidity)... than other animal or vegetable oils.”
Seems like it not going rancid is as important as any lube properties.