Considering the global distribution of ursid species, it’s not surprising that bears—and bear parts—have made their way into the stories, cuisine, and medicinal practices of cultures around the world. One particularly versatile element has been used for everything from lamp oil to hair tonic, but what is it about bear fat that makes it so unique? 

The off-white, waxy substance we think of as bear fat is technically a connective tissue known as adipose. It serves multiple purposes in the body, including energy storage, insulation, and protection of vital organs. Under a microscope, adipose is an aggregation of fat cells (adipocytes) interspersed with blood vessels and other supporting parts. Each fat cell is surrounded by an outer membrane, while the majority of its internal space is taken up by a sac or vacuole dedicated to lipid storage.  

When bear fat is rendered into oil, also known as bear grease, stored lipids are released from the cells and separated from the other parts of the adipose tissue. The most common method used for rendering is low, slow heat, but other methods are available for laboratory and medicinal applications. In addition to releasing lipids, rendering bear fat removes moisture. While bear oil is considered fairly resistant to spoilage, leaving water or tissue parts behind can reduce its shelf life. 

At a chemical level, lipids are a group of organic compounds made of carbon, hydrogen, and oxygen: examples include oils, waxes, certain vitamins and hormones. Lipids serve many roles in nature, but those found in bear fat are stored in the form of triglycerides and used for energy. As the name implies, triglycerides are composed of a glycerol backbone and three fatty acid chains (picture a fork with three tines). Hundreds of different fatty acids have been described in nature, but only a few are considered common or significant. Fatty acids can be divided into two major groups, saturated and unsaturated, based on the chemical bonds they contain. Plants and fish tend to have more unsaturated fats compared to red meats and dairy. Bear oil contains a mixture of saturated and unsaturated fatty acids that vary according to the bear’s diet. 

There is surprisingly little published information about the chemical properties of bear fat, but two papers dating back to the 1940s provide some baseline information about the composition of samples from two American black bears (Ursus americanus) compared to a handful of earlier reports across bear species. The chemists who analyzed those samples reported that 60 to 80-percent of the fatty acids in bear grease were unsaturated; because saturated fats have a higher melting point than unsaturated fats, this range also tracks with variation in the melting point of bear fat from 23° F to 99.5° F (-5°C to 37.5°C). When cooking, the melting point translates to the consistency of the rendered fat at room temperature as well as its smoke point. For the sake of comparison, duck and beaver fats can exceed 65 and 80-percent unsaturated fat respectively and are both essentially liquid at room temperature. 

At least nine different fatty acids have been identified in bear oil, and there are likely others since this subject is relatively understudied. Which fats are present and at what quantities depends on the diet of the bear when the fat was made. One of the most abundant fatty acids in bear grease is usually oleic acid, a common unsaturated fat that is also the major component of olive oil. Two other fatty acids detected in bear oil are linolenic and linoleic acids. Also known as omega-3 and omega-6 fatty acids, these unsaturated fats are considered essential nutrients for humans because our bodies need them but cannot make them. It may also be the linoleic acid in bear oil that contributes to another of its most touted uses - hair growth.  

As far back as the 17th century, bear oil was recommended as a treatment for baldness. Also considered a conditioner to prevent brittle hair and dry scalp, bear oil remained a popular hair treatment into the early twentieth century. While some historic practices prove ineffective (and occasionally dangerous) in the light of modern science, this one may hold merit. Linoleic acid from other sources has been shown to stimulate specialized skin cells responsible for hair growth, and a recent study examined whether ointments containing highly purified bear oil from Asiatic black bears (Ursus thibetanus) could stimulate hair growth in lab mice. The researchers reported increased growth as well as hair length and weight in the treated mice. 

In addition to cooking and hair care, bear oil was historically used for a multitude of purposes including lamp oil, skin care, wound treatment, and leather waterproofing. With the use of modern technology, bear fat can also be a powerful tool to help us learn more about bear biology, specifically diet. We know that bears are quintessential omnivores, and the composition of their fat reflects their diet in something known as a fatty acid or FA signature. By analyzing the FA signature of bears, as well as common prey species, estimates can be made about the proportion of certain foods used by a bear population. Additionally, some fatty acids are rarer than others and their presence may point to a specific food source or prey species. Finally, monitoring the fatty acid composition of bears from a single population over time can demonstrate year-to-year variation in bear diet that may correspond to changes in food availability or preference.  

Samples for fat analysis may come from harvested or otherwise deceased bears, but they can also be collected as a biopsy from live (preferably anesthetized) individuals. Since the most abundant and consistent fat on bears is found under the skin and over the rump, fat biopsies can be collected with very little risk to the animal. This helps researchers study diet more efficiently without impacting local populations or the conservation status of imperiled species. 

Even if you’re not a researcher or a chemist interested in the geekier properties of bear fat, a quick look at this amazing substance is a good reminder to use what we can from our harvested game and to make the most of nature’s bounty. 

References: 

Rasmussen, RA, PW Morgal, EJ Miller. 1943. Composition of fat from a North American black bear. Oil & Soap 20:159-161. doi: 10.1007/BF02640159. 

Sell, HM, BM Taylor, EJ Miller. 1948. The Identification of the Fatty Acids of the Fat from a North American Black Bear. The Journal of the American Oil Chemists’ Society. 

Thiemann, GW. 2008. Using fatty acid signatures to study bear foraging: technical considerations and future applications. Ursus 19:59-72. 

Wang, Z, Q Wang, Y Jin, K Guo, X Wang, X Feng. 2024. Optimization of Bear Oil Extraction Process and Hair Growth Activity. Molecules 29:1311.