Cagle's Map Turtle
One of the world’s most range-restricted map turtles lives only in the Guadalupe River system, where clean current and basking wood are essential habitat.
Artwork inspired by David Bates
Cagle’s map turtle is confined to the Guadalupe River drainage. Like other map turtles it is strongly aquatic and quick to drop from basking logs. Females become substantially larger and broader-headed than males, reflecting different feeding abilities; both carry fine yellow head lines and a keeled, patterned shell.
Low flow, degraded water quality, impoundment, loss of woody basking sites, disturbance, road mortality of nesting females, and illegal collection threaten a species with nowhere else to go. Scan downstream with binoculars from a fixed point. Repeatedly flushing a log costs turtles heat and feeding time.
- Status
- State threatened Texas river endemic
- Best clue
- Fine head stripes and a serrated river shell
- Texas habitat
- Flowing Guadalupe River channels with basking snags
Quick guide
- Observe
- Approach basking logs obliquely and stop if the first turtle drops
- In the field
- Slow on river roads during nesting season and let turtles continue their original direction
Recognize it in the field
- Range
- Read only the Guadalupe River system; geography is part of identification when identifying Cagle's Map Turtle.
- Head
- Compare many fine yellow lines with one broad ear patch; let turtles continue in their original direction.
- Shell
- Flowing Guadalupe River channels with basking snags; the appropriate active season.
- Ethics
- Use binoculars and never collect, handle, or reveal nest sites.
Good to know
Several map turtles look similar, and photographs without drainage information are easy to misidentify. Pet-trade images can also mix species; record shell, head, size, and exact river system without publishing a sensitive nesting point.
Notice these
- Fine head stripes and a serrated river shell
- Flowing Guadalupe River channels with basking snags
- State threatened Texas river endemic