Here's why:
* Different Species: Monkeys and dogs are very different species. They belong to different families (primates and canines, respectively).
* Genetics: Their genetic makeup is vastly different, making it impossible for them to reproduce together.
* Biology: The physical structures and reproductive processes of monkeys and dogs are incompatible.
It's important to remember that animals can only reproduce within their own species.
Perhaps you're thinking of a fictional creature, like a "monkedog"? In that case, let your imagination run wild! You could imagine a creature with the agility of a monkey and the loyalty of a dog.