Reptile: Monitor Lizard

Monitor lizards, large and sometimes fearsome lizards common throughout Africa, the Indian subcontinent, Southeast Asia, and Australasia, aren't just big and scary: they're also among the fastest learners in the reptile world. Monitor lizards have been proven to be able to count--not just know which of a group has the highest number of objects, but to know exactly which that number is. (You can read more about that experiment here.)

Source: Here