If you keep your turtles indoors, it is a good idea to cover their enclosure. Cats and dogs love to play with turtles. In the best case, the turtle is picked up, carried around, and let go. In the worst case, the turtle is bit, mauled, and killed. The smaller the turtle, the higher the risk. A cat will eat a crunchy baby turtle, if for no other reason than that it's fun to crack the shell. A dog will rolla turtle around and play with it, which can do a lot of damage to a turtle.
Please, cover your indoor enclosures if you also have a dogor a cat (or a ferret, or any other predatory pet).
PS: I have heard of exceptions, where dogs or cats make friends with turtles. Never let them be together unsupervised.