Simplify the following text for a Grade 5 native English-speaking person.
Original: However , their coats are endowed with unusually stiff guard hairs that function similarly to the spines of a hedgehog ; this trait is the source of the common name , spiny mouse .
Simplified: Their coats have unusually stiff guard hairs that work the same way as the spines of a hedgehog . These stiff hairs are why they are called the spiny mouse .