* Distinctive features: Hedgehogs possess several anatomical and physiological traits that distinguish them from other mammals. These include:
* Spines: The most obvious feature is their spiky coat of spines, which are modified hairs and serve as defense mechanisms.
* Small size and stout body: Hedgehogs are generally small, with a compact and rounded body shape.
* Short snout and pointed head: Their snouts are relatively short and their heads are pointed, aiding in foraging for insects and other small prey.
* Nocturnal lifestyle: Hedgehogs are primarily nocturnal, active during the night and sleeping during the day.
* Shared ancestry: Genetic studies have revealed that hedgehogs share a common ancestor with other insectivorous mammals, such as shrews and moles, but are distinct enough to warrant their own order.
* Fossil record: The fossil record provides evidence of the evolution of hedgehogs over millions of years, showcasing their unique characteristics and demonstrating their distinct lineage.
In summary, hedgehogs are classified as Erinaceomorpha based on their unique physical traits, evolutionary history, and distinct lineage that sets them apart from other mammal orders.