how do you tell the sex of a turtle?

[travis66]

my girlfriend asked me the other day because she just got a new baby red ear slider.i dont know so i figure i would turn it over to the experts here.thanks
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[JuliusSqueezer]

most male turtles have a somewhat concave plastron..(dented belly shell) This allows him to steady himself when mating without falling off. Females often like to walk while mating for some reason. Kinky eh? If you have 2 of the same approximate age/size you can also compare the tails. Males have a thicker tail.

With sliders...the concave is only slight unlike the deep concave of box turtles and some tortoises. the tail is thicker on the male and the front claws are longer.
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