The best indoor rat traps

Pre-bait, or none of this works

Rats are neophobic: a new object in a familiar environment is treated as a threat for days, and a rat will detour around a trap it has walked past twenty times.

So before anything else — put the traps out baited and unset for three to five nights. Let the rats feed off them with nothing happening. Then set them all on the same evening.

This matters more than which trap you buy. It is also why you should not set one trap and wait: one trap catches one rat and educates the rest, because the survivors associate the event with the object. Six traps armed simultaneously after pre-baiting takes out a meaningful share of the group in a single night.

If you have not confirmed the animal, mice vs rats takes a minute — a mouse trap will not kill a rat, and mouse traps vs rat traps explains why that failure is worse than catching nothing.

What indoors changes

You have to handle the result in a room you live in. This is the strongest argument for an electronic trap indoors: the rat dies inside a plastic tunnel, an indicator light tells you there has been a catch, and you tip it into a bag without seeing much or touching anything. Releasing a spring bar over a dead rat on a kitchen floor is a job people postpone, and a sprung trap catches nothing while it waits.

Pets and children are in the same rooms. A full-size rat snap trap has enough spring force to break a small dog's toe. Indoors, that means either an enclosed design — where the mechanism sits inside a tunnel or a locked box — or nothing. Pet-safe rat traps covers it properly.

Poison is at its worst indoors. A poisoned rat dies in a wall cavity of the house you live in, and the smell runs for weeks with no way to reach the source. Rat trap vs poison is the full argument.

Where to set them indoors

Rats run structure and will not cross open floor if they can avoid it. Look for greasy rub marks — a dark smear along a wall, a pipe run or a joist at rat-shoulder height. That is unmistakable once you have seen one, and it tells you exactly where to set.

Productive indoor locations, in rough order:

• Along the wall behind kitchen base units and appliances
• Under the sink, around pipe penetrations
• Along the basement or cellar wall, near where services enter
• Behind stored boxes in a utility room
• Along a loft or crawl space joist run — though for those, attic traps and crawl space traps are the more specific pages

Perpendicular to the wall, trigger end touching it, in pairs. Secure the bait so it cannot be lifted cleanly — tie a strip of bacon on with cotton thread, or press peanut butter well into the trigger. A bait a rat removes without firing the trap is a lesson that the trap is harmless. Best rat trap bait.

Enclose the set

Even where no pet is in the house, boxing an indoor rat trap helps: rats prefer approaching through a covered tunnel, so a trap inside a box or a locked station catches more, not less.

A sturdy plastic tub or a length of large-diameter drainpipe with rat-sized holes works. A locked station does it better and survives being knocked about. Do not use cardboard for rats — a determined animal will go through it.

The week to expect

• Nights 1-2 after arming: most of the catches.
• Nights 3-7: a tail, usually concentrated at one or two traps, which tells you where the remaining route is.
• Any rat that survives a trap will not approach that trap again — that is trap shyness, and it needs a reset rather than more of the same.
• Five consecutive clear nights on baited, armed traps still sitting on the runs means the trapping is done.

Then seal, or repeat this next year

A rat gets through a gap of about 20 mm and can enlarge a smaller one by gnawing. Close every penetration at the foundation line, damaged air bricks and crawl space vents, gaps under siding, perished door seals and broken drain covers. Hardware cloth, tightly packed steel wool with sealant over it, or mortar — rats chew through expanding foam and soft plastic.

How to get rid of rats has the full sequence, and it is worth reading before you buy anything.