They're very small and hide along sewn ridges, seams, and between layered items such as bed framing.
When they feed, they tend to feed in somewhat of a straight line. If you can imagine your arm or leg lying along the mattress which allows the bed bugs to line up and feed, sort of like pigs at a trough, to use a rough analogy. Whereas other insects such as fleas or mosquitoes would feed sporadically in various places across the body and it wouldn't be confined to a linear grouping of bites.
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