How do urban mice adapt to their environments?

House mice (Mus musculus) can be found any urban environment – infesting houses and premises with glee. These small rodents move freely between locations along so called ‘mouse motorways’ – the underground cable and pipe tunnels we have built beneath our feet.

They are also often ‘delivered’ to the doorsteps of businesses through shipments from manufacturers and vendors, potentially establishing a chain of infestation along the logistic routes that end with your local grocery store or nearby shopping center.

Mice will relocate

Given a stable environment with plenty of food, mice can remain within a small area of up to 10 yards.

However, in many urban cities, exponential mouse population growth forces mice on to search for new food sources and more desirable habitats. Mice have been tracked as moving more than half a mile in one night as they set out to discover new locations to infest.

Mice are not commonly seen outside buildings, so ‘hitching a ride’ on packaged goods or using underground passageways in urban environments are the main means by which they enter a new site.

Once inside, mice will start to explore the many internal ducts, voids, raised flooring and ceilings that allow them access to the entire building – from the basement to the top floors. It could even be argued that the increase in cabling required to provide speedier internet services have only served to make this situation worse.

Mice can get through barriers

Mice, like rats, are very good climbers of almost any surface and even possess the ability to scale smooth surfaces by bracing their back against a pipe or similar structure. Any barriers along the way can be circumvented by adult mice if there is a mere gap of half an inch for them to squeeze under – a young mouse can squeeze under gaps even smaller and it is often these younger mice exploring new territory.

Mice are very neophilic, which means it is in their nature to investigate new areas and objects in their environment. This is part of their foraging strategy as they explore their environment, sampling anything that may be of food value as they roam. A mouse needs only around 3 grams of food a day, but will often pick this up from multiple locations rather than just one source – up to 40 different points in 24 hours, as demonstrated in an experiment.

Mice need little food and water

If mice find moist food (containing as little as 15% water by weight) then they do not need to drink – these factors mean it requires very little to sustain a small mouse infestation.

While exploring and feeding, mice leave behind some rather unpleasant signs of their presence. Although there is no truth to the myth that mice have no control of voluntary urination or defecation, they do leave little ‘dabs’ of urine wherever they explore and feed.

These spots of urine contain odors that mice use for social communication – in severe infestation these spots can be added to, and combined with the grease from their fur, can form ‘mouse pillars’ up to 1cm tall (these are more likely seen below ground in urban scenarios).

With 3 grams of food consumed by a single mouse in a night, around 80 droppings are produced – deposited everywhere the mouse has been. This seems an astonishing number, but was recently verified within Rentokil’s own laboratories.

While exploring, mice tend to gnaw on many of the items they come across for possible consumption of food, nesting material, to create a hole to pass through or simply out of investigative curiosity.

This can cause many issues as damage to electrical or signal cabling can lead to fire, loss of vital communications or control over critical machinery.

Rodent incisors are designed for gnawing. Growing 0.4mm/day, they are ground to a point by gnawing and this makes their teeth strong enough (5.5 on Mohs hardness scale) to gnaw through most materials, including the softer metals and potentially even steel – making it extremely challenging to protect cables from damage.

Mice adaptations lead to infestations

Safe shelter and a relatively small amount of food is all it takes to sustain an infestation of mice. If conditions are favorable, then a few intruding mice can breed rapidly to form a larger problem. Rodents have a gestation period of only 3 weeks, and mice can produce litters of up to 16 pups. These pups take only 8 – 12 weeks to mature and reach a stage where they can start breeding.

While these optimal breeding rates are unlikely in most urban settings, it is clear that vigilance and a proactive rodent detection program are crucial in ensuring this does not occur.

For more information please see our rodent control page.

To learn more about how Ehrlich can help you get rid of mice in your home or business, call at (888) 976-4649 or contact us online.