QUESTION: The rut in Texas varies so much by region. Why is it for example in Goliad county the rut can start in the later part of October and run into November, and then just a short 35 mile drive into Bee county the rut will start in the early parts of December and run into early January?
– Jason F.
ANSWER: Texas is a prime example of varying peak rut dates within a single state. A recent study by the Texas Department of Parks and Wildlife showed the Gulf Prairies and Marshes region of southeast Texas had two peaks. The northern study area had a peak of September 30, while the southern area was a month later around October 31. Just north, the Post Oak Savannah rut peaked November 10, while the Pineywoods eco-region of northeastern Texas experienced peak breeding dates of November 22 in the northern portion and November 12 in the southern part.
As you move west into what they called the Cross Timbers region, the rut peaked between November 15 and 17, while the Rolling Plains of north-central Texas had peaks of December 3 in the north and November 20 in the south. The Edwards Plateau experienced three peaks: November 7 in the eastern part, November 24 in the central portion and December 5 in the west. The peak date for the Trans-Pecos of southwestern Texas was December 8. The South Texas Plains had the latest ruts in the state: December 16 In the eastern part and December 24 in the west.
Why? There are likely several contributing factors, but the biggest is natural selection. Deer, wherever they occur, adapt over time to breeding at a time when subsequent fawn drop occurs at a time when fawns will have the greatest likelihood of survival. In the north, they must be born late enough that there is ample food - first for the nursing does, and later for the growing fawns - and early enough so fawns can grow enough to survive their first winter. In the south there is less selective pressure, and so, greater variability. In Texas, it is probably tied more to the rainy season, when moisture will provide the highest levels of nutrition. Of course, rainfall amounts are far less predictable, which also likely accounts for greater variability.