Here's why:
* Spine bearing: Hedgehogs are known for their spines, which are modified hairs.
* Nocturnal: Hedgehogs are primarily active at night.
* Insectivorous: Hedgehogs feed mainly on insects, worms, and other invertebrates.
While other mammals like echidnas and porcupines share some of these characteristics, hedgehogs are the most common and widespread animal that fits all three criteria.