Realizing that this varies with locale & food availability.

Caught two Northwesterns today. One is about 17 inches long, the other is smaller, maybe 13 inches long. Both are from wetlands near a river, with abundant food & cover.

Since they average 9.5 inches at birth, would you guess that the larger is a 2006 hatchling, and that the smaller is a 2007 hatchling?