Bed bugs live by feeding exclusively on blood, hiding in tight spaces near their hosts during the day, and emerging at night to feed. They spend the vast majority of their lives tucked into cracks and crevices, venturing out only for meals that last about five minutes. Understanding how they eat, where they hide, how they reproduce, and what kills them gives you a practical edge in preventing or dealing with an infestation.
Where Bed Bugs Hide
Bed bugs are creatures of proximity. About 85% of a bed bug population lives in or near the bed itself: along mattress seams and tufts, in the wood joints of box springs, in cracks and joints of bed frames, and behind headboards. The remaining 15% spread to upholstered furniture, bedroom cabinets, baseboards, behind loose wallpaper, picture frames, and even inside electronics and appliances.
They strongly prefer surfaces made of wood, paper, or fabric over metal or plastic. This is why wooden bed frames and upholstered furniture are prime real estate for infestations, while metal frames offer fewer footholds. Their hiding spots are almost always within six feet of where a person sleeps or rests. They cluster together in these harborages, drawn partly by chemical signals that encourage group living. These aggregation pheromones help bed bugs find each other and settle into shared hiding spots, which is why you’ll often find dozens packed into a single crack.
How They Find and Feed on Hosts
Bed bugs locate sleeping humans by detecting body heat and the carbon dioxide you exhale. They become active at night, travel to the host, and feed for roughly five minutes before retreating to their hiding spot. During feeding, a bed bug uses two hollow tubes in its mouthparts. One injects saliva containing a substance that prevents your blood from clotting, while the other withdraws blood. That anticlotting agent in their saliva is what causes the itchy, red welts many people develop afterward, though reactions vary widely from person to person.
A blood meal is not optional. Every bed bug at every stage of life needs blood to survive and develop. Nymphs (juveniles) must feed at least once before they can molt to the next growth stage, and they pass through five molts before reaching adulthood. Adults continue feeding regularly throughout their lives, and females need blood meals to produce eggs.
Life Cycle From Egg to Adult
A bed bug’s life begins as a tiny, pale egg about the size of a pinhead, glued to a surface in or near a harborage. After hatching, the nymph passes through five stages called instars. At each stage, it must take a full blood meal and then molt, shedding its exoskeleton to grow larger. Each instar looks like a smaller, lighter-colored version of the adult. Under favorable conditions with regular access to blood and room temperature surroundings, the entire journey from egg to adult takes roughly five to six weeks.
Adults are flat, oval, reddish-brown, and about the size of an apple seed. After feeding, their bodies swell and darken to a deeper red. A well-fed adult female can lay several eggs per day, and over her lifetime she may produce hundreds. This reproductive output is what makes even a small number of bed bugs dangerous: a single fertilized female introduced to a new location can seed an entire infestation within weeks.
How Long They Survive Without Food
Older studies from the 1930s and 1940s claimed bed bugs could survive over a year without feeding, but those experiments were conducted in unheated UK homes where temperatures dropped below 40°F. Cold slows a bed bug’s metabolism dramatically, stretching survival time. Modern research on bed bugs collected from American homes paints a different picture. At room temperature, a starved bed bug at any life stage will die within about 70 days on average.
This matters practically. If you’re hoping to starve out an infestation by leaving a room or apartment vacant, you’d need to ensure no host is available for at least two to three months, and that temperatures remain at normal indoor levels. Lower temperatures extend their survival, making winter “starvation strategies” less reliable than many people assume.
Temperature Extremes That Kill Them
Heat is the most reliable weapon against bed bugs. Adults and nymphs exposed to 113°F die after 90 minutes of constant exposure. Raise the temperature to 118°F, and they die within 20 minutes. Eggs are harder to kill: they require 118°F for a full 90 minutes to reach complete mortality.
These thresholds explain why professional whole-room heat treatments work. Technicians heat a space to at least 113°F and hold it there for an hour or more, using powerful fans to create air currents that heat bugs rapidly even inside their hiding spots. Sensors placed throughout the room confirm every area has reached lethal temperatures. For smaller items, a household clothes dryer set on high can kill all life stages, including eggs, in about 30 minutes as long as the dryer isn’t overstuffed.
Cold can also kill bed bugs, but it works much more slowly and requires sustained temperatures well below freezing for several days, making it less practical for most situations.
Why Infestations Grow So Quickly
Several features of bed bug biology work together to make populations explode. Females produce eggs continuously as long as they have access to blood. Each generation from egg to reproductive adult takes only about five to six weeks. And because 85% of the population stays concentrated near the bed, they have easy, reliable access to a host every night.
Bed bugs also spread to new locations passively. They hitchhike on luggage, clothing, used furniture, and other belongings. A single pregnant female in a suitcase can start a colony in a new home. They don’t fly or jump, so all movement is either crawling short distances to feed or riding along on objects people carry. This is why infestations commonly appear after travel, after acquiring secondhand furniture, or in multi-unit housing where bugs migrate through wall voids and shared plumbing channels between apartments.
What Keeps Them Alive
Bed bugs are well adapted to living alongside humans in climate-controlled indoor spaces. Their flat bodies let them squeeze into crevices as thin as a credit card. They’re nocturnal, feeding when hosts are least likely to notice. Their saliva numbs the bite site, so most people don’t wake during feeding. And their preference for hiding within six feet of the bed means they never have to travel far for a meal.
They thrive at the same temperatures humans prefer, roughly 65°F to 85°F. Outside this range, their development slows or stops. They can’t survive outdoors in most climates for long and have no real habitat outside of human dwellings. In a very real sense, bed bugs live the way they do because human homes provide everything they need: warmth, darkness, tight hiding spots, and a sleeping host just a few feet away.