Fat is more energy-dense than protein and carbohydrates, it is not only an energy deposit but also an organ with many functions such as cushioning and metabolism regulations. I want to know are animal fats similar across species (composition & function), specifically what animal has fat with the highest energy density?
In both humans and animals, the body fat stores appear as triglycerides, which can be composed of different fatty acids, but they all have about 9 kilocalories per gram (USDA).
There can be different amounts of fat in different fat cells, so there can be slightly different amounts of fat in 100 grams of different types of fat tissue.
Calories in 100 g of fat from different animals:
The fat mentioned above was white fat, which appears as a single fat droplet in a fat cell. Humans and some animals, especially rodents and bats, also have different amounts of brown fat in which the fat cells contain a lot of mitochondria and the fat is present in multiple droplets, so, logically, brown fat tissue has lower energy density.