They have VERY busy noses; they smell everything they can!

People who have had experience with small pet rodents, or with ferrets seem
to ask this question most often.  Hedgehogs do not have scent glands like
ferrets, and as long as their cage or pen is kept reasonably clean there is
generally very little odour.  Most (some?) hedgehogs can be trained to use a
litter box, making the task of keeping the cage clean that much easier.  Even
those that don't adapt to using a litter box will often use one area of their
cage or pen for this which assists in cleaning.

While hedgehogs do generally have little in the way of odour, what you feed
them can affect whether or not their droppings smell.  Generally the more
``wet'' food you feed a hedgehog, the more their droppings, and their
environment, will smell, although brands and types of food can have as great
an effect as just wet versus dry foods.  Also, Pretty Pets hedgehog food is
has been reported to result in smellier than average droppings [6.3].

Younger hedgehogs and pregnant/nursing females also tend to have much
stronger scented urine and droppings.  If your hedgie is still in his or her
`teens' just be patient, and keep cleaning the cage, often.  They will almost
certainly grow out of it.

If you are finding your hedgehog pen tends to smell, try changing the blend
of food he is getting, or just clean house on him a bit more often.