Are you REALLY never more than six feet from a rat? Here's the 'science' on that

If you feed birds, have a compost heap or have decking in your garden, there’s a good chance that rats are on your mind, if not in your garden, as we head into the autumn ‘rat season’.

But how much of our fear is based in reality, and how much of this fear is just misconceptions bouncing around inside our heads? Here’s our reality check on some of the biggest myths (and some of the most chillingly little-known facts) on the world’s most unloved rodent.

1: “You’re never more than six feet from a rat.”

First, relax: this one is false, although it may have been not far from the truth once, and in only the most deprived locations.

Part of the problem is the assumption that populations (human and rodent) are consistently distributed, when they’re highly varied, and that localised rat numbers are not dependent on numerous environmental factors, when they obviously are.

Whatever the actual figure, there’s no doubt that rats do like to be relatively near to humans – and particularly the ample shelter and food that we offer, usually by accident. Most urban rats will be living in the comparative comfort of drains and sewers, and will emerge only at night, but they’ll happily break that habit if we make things comfy for them in the garden or allotment.

2: “There’s one rat for every person in the UK.”

Disturbingly, we just don’t know about this one; modern estimates from the British Pest Control Association put rat populations at between 10 and 120 million, against the UK’s human population of 69 million.

According to Robert Sullivan, author of Rats: Observations on the History & Habitat of the City's Most Unwanted Inhabitants (Granta, 2005), this claim goes back to an estimate made in WR Boelter’s The Rat Problem in 1909.

Following what would today seem a profoundly unscientific method, Boelter surveyed inhabitants of the English countryside on whether they thought one rat per acre of cultivated land was a reasonable estimate.

Based on the conclusion that this was in fact the case, the figure of roughly 40 million acres of cultivated land equated to roughly 40 million rats, which in turn roughly equated with the population of England at the time; and thus ‘one rat for every person in the country’ was born as a lasting rule of thumb.

However, the lack of certainty on total rat numbers probably doesn’t really matter, as it’s where they are in relation to us that really counts.

Their encroachment on our space tends to be driven by the availability of food, and the relative lack of human footfall to disturb them.

For this reason, Britain’s gardeners may be best served to keep a particular eye on their allotments rather than their gardens as we head into winter; warm, dry compost heaps make for a cosy retreat from winter cold, as do the foundations of semi-derelict sheds, seldom visited by humans between the final planting of garlic in autumn and the first pre-season clear-up.

3: “Rats will attack if cornered.”

Not usually. Wild rats are wary animals that will avoid humans whenever possible. Bites are rare and tend to happen only when an animal is trapped, injured or handled.

For gardeners, the bigger risk is startling one in a compost heap or under a shed, but rats will almost always bolt to escape in such situations. Still, thick gloves are always a good idea when clearing overgrown corners or shifting old timber, to protect against general injuries and infections – as well as the far less likely outcome of a rat bite.

4: “You can catch nasty diseases from rats.”

This one is true — but the danger is often overstated or misunderstood.

Rats can carry a number of pathogens that affect humans, including leptospirosis (Weil’s disease), hantavirus and rat-bite fever. In the UK, the most relevant is leptospirosis, spread through contact with rat urine in water or damp soil.

Gardeners are advised to wear gloves, cover cuts, and wash their hands after contact with compost heaps or work inside and around ponds. For most of us, the risk remains small, but it’s real enough to merit good hygiene.

5: “Certain smells or gadgets keep rats away.”

Maybe – a bit. Peppermint oil, ultrasonic buzzers and home remedies are the talk of social media, but the evidence is mixed.

Rats quickly adapt to new stimuli, and unpleasant smells or sounds – unless implemented with real zeal and consistency – won’t deter them for long if they’re strongly motivated by the possibility of food and shelter. It’s a bit like using moss killer on a shaded, damp lawn; you may get rid of the moss for a while, but the cause is still there, and the moss will probably return.

The proven methods are boring but effective: seal up access holes under sheds, keep bins closed, clear bird-seed spills and avoid leaving standing water.

Video: Alan’s ultimate guide to keeping rats out of your garden

6: “Rats breed like… rabbits.”

They can, if conditions allow. Female brown rats are capable of producing six litters in a year, each with up to 12 pups. The gestation period is just three weeks.

Rat pups grow fast and can themselves breed three months from birth, so a population of two rats can become hundreds within half a year – considerably faster than even the most amorous of rabbits.

In reality, reproduction and survival is governed by environmental factors such as temperature, predation and the availability of food, so reproduction rates are unlikely to be quite as high in most instances.

Conditions for rodent reproduction and survival are best in the warmer months, so numbers are likely to be at their highest in late summer into autumn; the reason we humans become so aware of rats in autumn is precisely because these populations are seeking warmth from encroaching cold, and food where supplies are running down.

Look out for these signs of rats in your garden

• Greasy runs or tracks alongside walls, fences, or buildings, typically up to 10cm wide
• Cylindrical droppings, around 15mm long and 5mm wide
• Gnawed wood or plastic, especially where food is stored, or to gain access to compost bins
• Parallel tooth marks in crops such as sweetcorn or potatoes
• Signs of a rat’s nest, often appearing as a heap or loose ball of soft or shredded materials, using sticks, leaves, paper or cardboard
• Burrows with a smooth opening, usually 6-9cm across, which may be the entrance to a rat’s tunnel

7: “It might just be mouse droppings.”

This one is easy: if it’s larger than a grain of rice, about 1-2cm, then it’s rats. If it’s smaller, it’s mice.

Another sign to look out for is the presence of greasy residues. Rats are extremely short-sighted, so they use vertical surfaces such as walls as a guide, as well as an instinctive protection against predation, leaving telltale staining on these surfaces.

8: “Rats will get worse with climate change.”

This is probably true. Milder, later winters mean greater access to food, reduced hazardous exposure to freezing temperatures and longer breeding seasons.

A 2025 study led by Johnathan Richardson of the University of Richmond, in Virginia, USA, reported a significant rise in complaint calls to city pest control departments, using data going back as far as 17 years. The study linked climate change as a cause, noting that cities where temperatures were rising fastest had larger increases in rat activity and sightings.

This research has since been criticised for its use of messy proxy data rather than actual rat populations, but whatever the precise truth, the logic that longer summers and shorter, warmer winters would make life easier for rats to survive and reproduce is hard to dispute.

9: “A big rat can weigh six kilos…”

Yes, but only if phrased in the past tense. This is the now-extinct Timor giant rat, which has been estimated to weigh up to 6kg, a little more than the average house cat.

This was one of 13 species uncovered by excavations in 2010 on the island of East Timor, a location known to palaeontologists as a global hotspot for rodent evolution.

The Timor giant rat survived until as recently as the 10^th century AD, so it may have been a reasonably common sight for the island’s human inhabitants, who arrived 40,000 years ago.

UK readers may be relieved to hear that the brown rat, by far our most common species, rarely exceeds 500g.

PHOTOS: GETTY