Probably run over by a lawnmower :(
Cool observation! This tortoise was seen on the shoulder of the road, and has successfully escaped kidnapping and a domestic dispute. She's even one of the oldest participants of a 50 year telemetry study! Neat to see her alive and roaming.
Here's a little history for this critter:
Old shell fragment consisting of several outside scutes. Scrape marks on edges of shell may be from predator or rodent teeth. Not sure if hole in shell is from canine. Occasional holes in ground in general area suggest continued occupation by gopher tortoises. Grassland and oak hammock.
The gopher tortoise (Gopherus polyphemus) is a species of the Gopherus genus native to the southeastern United States. The gopher tortoise is seen as a keystone species because it digs burrows that provide shelter for 360 other animal species. They are threatened by predation and habitat destruction.