Giant clam

The Giant Clam was one of the unwanted creations of Davros' experiments. They were kept under the Kaled Dome in a cave leading out to the Wastelands. There was more than one Giant Clam; five were seen. The Fourth Doctor said its bite had the force to crush bone and commented that it was interesting. It is unknown what other animal mutations Davros had created. (TV: Genesis of the Daleks)