Categorize the following two items as either a mammal or a reptile:
Axolotl, Dolphin
Axolotl: Reptile
Dolphin: Mammal
Complete the following task based on the instruction and optional input provided.### Instruction:
Categorize the following two items as either a mammal or a reptile:

### Input:
Axolotl, Dolphin

### Output:
Axolotl: Reptile
Dolphin: Mammal