US Geological Survey


Date of this Version



Published in JOURNAL OF WILDLIFE MANAGEMENT 71(3):920–923; 2007.


I present marrow fat (MF) data from a large sample of white-tailed deer fawns killed by wolves and a sample of fawns that died by accident in a single area, and I use these data to explore the extent that poor nutritional condition may have predisposed fawns to wolf predation. Percent MF of 110 5–10-month-old white-tailed deer (Odocoileus virginianus) fawns killed by wolves (Canis lupus) from November through April 1984–2002 in northeastern Minnesota, USA, was lower than MF for 23 fawns killed by accidents in the same area and period. The MF of both male and female wolf-killed fawns decreased over winter. The MF of male fawns decreased as a snow-depth index increased, but MF of females showed little relationship to the snow-depth index and was higher than that of males. Poor nutritional condition is one factor that predisposes deer fawns to wolf predation during winter and spring. This information expands our knowledge of wolf–prey relations by documenting that, even with younger prey animals that might be thought vulnerable because of youth alone, poor nutritional condition also is an important factor predisposing them to wolf predation.