If you are keen, you may spot a predator hiding among the cattails along the boardwalk. Sac spiders belong to a diverse group of spiders in the Clubionidae family. They are nighttime hunters, stalking and ambushing prey, they do not construct webs for hunting. They do, however, use their webs to curl leaves and construct hiding places during the day. When a female is ready to lay her eggs, she will create a chamber, like one shown above, and seal herself in with the eggs. This chamber will become her tomb; when the baby spiders hatch, she will become their first meal.