Fat reserves are known as good indicators of physical condition for several animal species. Usually prey animal physical conditions are determined for further analysis by prey selection patterns of carnivores. However, the most usable fat reserves (around heart, stomach, kidney) are usually consumed by predators, together with organs. The only available fat reserve for this kind of analysis is the long bones marrow fat. Since bone marrow fat is usually the last mobilized energy deposit of an organism, their mobilization is beginning after the depletion of other fat reserves. In this context, low fat content of bone marrow indicate the depletion of other fat deposits. Such as, a low fat content of the marrow can indicate certain levels of starvation due to several environmental factors (poor habitat, winter severity, etc) and/or physiological factors (young, old, sec, injured, etc). Very low fat content means the animal is near death. At the same time high fat content of the marrow cannot show with confidence that the animal was completely healthy or without problems.

We used the „dry-weight method”: 25-30 g fresh marrow measured after it was dried in 60-70 C. Drying was continued until periodic weighing showed no further reduction. The percent of dried marrow (containing fat and non-fat residues) can be used as an index of fat content.
We estimate the marrow fat content being between 84-89%. Our investigation can show that the red deer not suffering from malnutrition.