Mule deer does defend ALL fawns, Whitetail, eh, not so much

In fight or flight situations, female mule deer and whitetail deer behave differently.

Mule Deer Moms Rescue Other Fawns

By playing recordings of fawns being attacked by coyotes, researchers have been studying the behavior of mule deer and whitetail deer. They have found mule deer doe’s to be much more aggressive defenders of fawns whether they are their own or some other doe’s. Whitetail does, on the other hand respond tentatively to the cries of the fawns, quickly access the situation, and withdraw once they are aware this isn’t their fawn doing the bawling.

"Having a rigid and aggressive response to the simple sound of a fawn distress call may ensure effective defence of a female's own offspring, even though this means the female invests time and energy and puts herself at risk by helping many other animals. In contrast, a whitetail mother waits to assess whether a fawn is her own before she steps in to defend it. As a result, whitetail fawns suffer considerably more predation during the first months of life than do mule deer fawns."

Mule deer may have developed a more effective aggressive defence because they rely on fighting to protect themselves against predators year-round, while whitetails and many other species restrict aggressive defence to just the youngest fawns. Whitetails rely on flight rather than fight for most of their lives, so this may affect their ability to mount an aggressive defence," Lingle said.

This might explain why I see a lot of white tails disappearing into the forest during hunting season. The whitetail has got the same philosophy as a Rincewind (a "wizzard" on Disc World) when it comes to choosing fight or flight. Running from is much better than running to.

Still doesn’t explain why whitetail deer are encroaching on the mule deer habitat in the Midwest and apparently out competing them.