Porcupines float on water.
Porcupines are great swimmers. That is, some breeds of them are. The North American porcupine, the crested porcupine, and the brush-tailed porcupines all love swimming!
All porcupines have the ability to float, however, and may enter water as a way to escape an attack. Remember, these docile creatures will always attempt to escape rather than fight whenever they get the opportunity.