Here's why:
* They are mammals: Platypuses are mammals, and mammals generally have fur or hair, not scales.
* Their skin is smooth and waterproof: Platypuses have a dense, velvety fur that helps keep them warm in the water. Their skin is also covered in a special oily substance that makes it waterproof.
Scales are more commonly found on:
* Reptiles: Snakes, lizards, turtles, etc.
* Fish: Both bony and cartilaginous fish.
So, while platypuses are fascinating and unique creatures, their skin is not dry and scaly like a reptile.