The Turtles

In front of my office there is a pond. In this pond there are turtles. How did the turtles get there, one might wonder, as the pond is man made? And what's more curious: why are the turtles different species of turtle? They hang out on different sides of the pond and have turtle turf wars. Today I tried to take a picture for your viewing pleasure, but the camera was shot out of my hand by tiny turtle guns.