When hedgehogs are born their spines are just below the skin, so they don't cause their mother pain. They are blind at first, but after about 2 weeks their spines begin to show more, and their eyes open. Hedgehogs also have baby teeth, just like humans. These fall out by about week 3. Hedgehogs leave their nests when they are about 4 to 5 weeks old, and they then must learn to fend for themselves. 1 out of 5 hedgehogs die before they leave the nest.