Bed bugs preferentially feed on human blood, or if not available, they also feed on warm-blooded animals such as rodents, bats, birds, or pets. They hide during the day and feed during the night move fast and hide well because of their biological structure. At night, they feed on the host while asleep and they use their sharp beak or mouth system to pierce the skin of the host. A salivary fluid is injected containing anticoagulant substances so they can obtain blood.
Their dark hiding places are usually small cracks and crevices where they can fit themselves into. They prefer wood, paper, and fabric surfaces which are why you can usually see them in seams, tufts, and the folds of mattresses. When they spawn enough, their dwelling grounds will expand to the crevices of the bedstead and places under the bed. You can also see them in various places in the house, not just in the bedroom.