This is the hardest page on this site to write, and the one we think matters most. Almost nobody wants rats in their home, and this page does not ask you to.

What it asks is narrower: that the way we deal with them not poison the hawks, owls, and foxes that hunt them, and not inflict days of internal bleeding on an animal that feels it. Those two things are connected, and both point to the same practical answer.

It helps to start from what a rat is actually doing. A rat in a basement is not being malicious or invading anything — it is a small animal looking for food, warmth, and somewhere safe to raise young, and it has found those things where we happened to leave them. It has no concept of property, and no interest in us beyond avoiding us. Set that against what they are capable of — solving problems, recognising individuals, caring for their young and for each other — and they turn out to be genuinely remarkable animals. Worth knowing something about, even if you would rather they lived somewhere other than your walls.

There is even something to learn from them. Rats survive by cooperating: they nurse each other’s young, share food with hungry colony members, and will work to free a trapped companion with nothing to gain by it. For a coalition built on the idea that neighbors do better looking out for one another, it is a strange and useful thing to find the same instinct in an animal most people have been taught to despise.

What they look like

Norway rats are stocky and heavy-bodied, with coarse brown-grey fur, small ears, a blunt nose, and a thick scaly tail noticeably shorter than the head and body together. Adults typically run seven to ten inches in the body, with the tail adding a good deal more.

They are not native to North America — they arrived on ships in the eighteenth century and have lived alongside people ever since. Nearly everything about them is shaped by that association: they are creatures of basements, sewers, alleys, and burrows beneath structures, not of woodland.

Family life

Rats are intensely social. They live in colonies with recognisable hierarchies, groom one another, sleep piled together, and maintain networks of burrows with separate chambers for nesting and food storage. An isolated rat is a distressed rat.

Females can raise several litters a year, of perhaps six to twelve young, and mothers are attentive — retrieving strays, nursing communally with other females, and defending the nest. Young are weaned at around three to four weeks.

The reproductive speed is the reason poison never resolves an infestation on its own: a colony reduced by half rebounds within months, while the same conditions that supported it — food and access — remain unchanged.

And those conditions are ours. Rat numbers track the food supply almost exactly: a colony grows to the size the available food will support, and shrinks when it disappears. Overflowing bins, bagged rubbish left on the kerb, spilled birdseed, fallen fruit, food waste in the open — these are what set the population. We supply the conditions for rats to multiply, and then blame the rats for multiplying. Take the food away and the numbers fall on their own, without a single poison bait.

How they live

They are mostly nocturnal, excellent swimmers, and cautious in a way that has real consequences for how people try to control them. Rats show strong neophobia: they avoid unfamiliar objects and new food sources for days, sampling small amounts first. That caution is why bait works slowly, and why traps set carelessly are simply avoided.

They are also genuinely intelligent. Laboratory work has shown rats will free a trapped companion even when there is no reward for doing so, and will choose to share food with one; they can be trained on complex tasks, and appear to have some capacity to judge their own uncertainty. They emit high-frequency chirps during play and when handled gently, which researchers have compared to laughter.

None of this means a rat belongs in your kitchen. It does mean that how one dies is a moral question rather than a purely practical one.

Why the method matters

Anticoagulant rodenticides kill by preventing blood from clotting. The animal bleeds internally over several days, becoming weak and disoriented long before it dies. During those days it is also unusually easy prey — which is exactly how the poison reaches the hawk, the owl, and the fox that catch it.

A study of New Jersey birds of prey found residues of second-generation anticoagulant rodenticides in the large majority of red-tailed hawks and great horned owls tested. Those predators are the most effective and cheapest rodent control a neighborhood has, and poison removes them along with the rats. Our Q&A on rodenticides sets out the evidence and what to use instead.