I had assumed that water turtles did not make vocalizations like tortoises (maybe that's just because I don't have a water turtle), but my neighbor just posted this interesting article on her blog about how they do! I think it's awesome that mama water turtles can call to their babies and babies can synchronize hatching! Maybe this is old news, but has anyone heard of such behavior before?
http://thewildlife.wbur.org/2014/08/15/turtles-who-have-something-to-say/
http://thewildlife.wbur.org/2014/08/15/turtles-who-have-something-to-say/