There are two species of rats that you may encounter as a pest in the United States: the brown rat and the black rat, also known as Rattus norvegicus and Rattus rattus respectively. The latter (black rat) tends to live in more seaport areas, with brown rats sticking more inland.
Brown rats are larger than black rats, and there is some evidence to support the idea that both species of rat might actually be getting bigger as the years go on. With more rats choosing to live right alongside humans, and cleaning up the food waste that humans leave in their wake, it is no wonder that rats are doing the best out of any animal species right now.
The average brown rat can be brown, gray, or any combination of the two, including white, and usually tips the scales at around 1 pound in weight. The black rat, mostly black in color as the name suggests, is around half of that weight. Black rats also tend to be around half the length of brown rats: 3 inches long (minus tail) and 6 inches long respectively.
In the wild, rats only live for about a year on average, but they can live for a lot longer with the right living conditions. In captivity, with those perfect conditions, both brown rats and black rats have been known to live for up to 3 or 4 years.
Rats are well known for being able to breed quicker than most other animals, and a female in the right conditions can actually keep mating throughout the year, every 6 to 8 weeks or so. The female will only be pregnant for 3 weeks at a time, giving birth to around 5 to 10 babies each time, called pups, and be ready and raring to mate again as soon as a day or so afterwards.
At about 5 weeks of age, rat pups are sexually mature and ready to mate themselves, though some do take a little longer.
Rats can live anywhere. They're one of the most adaptable, creative, and determined critters on the planet, and they've learned to live in virtually every habitat on the planet. At present, Alberta is the only province in the entire country of Canada without rodent populations, and it can also boast of having the title: largest inhabited area on the planet without rats.
It is also believed that there are no rats on the entire continent of Antarctica, on Hawadax Island in Alaska, in certain areas of conservation and protection in New Zealand, and also on smaller or newer islands far away from mainlands.
Rats eat everything.
That's everything you need to know as far as a rat's diet is concerned: they will eat everything. They will eat good food and rotting food, the decomposing flesh on a carcass, and even the droppings of other animals if they can find some food remnants in there.
Rats literally eat EVERYTHING.
One of the biggest problems with rats (and there are a lot of big problems) is the fact that they urinate and defecate everywhere they go. In turn, this unsightly mess spreads diseases and communicates with other rats, telling them where to go, where's safe, where's not, where the food can be found, and a lot more besides. All the while you have those urine trails around your home, the pheromones will be attracting and communicating with other rats.
As well as diseases such as leptospirosis, hantavirus, toxoplasma gondii, listeria, and salmonella, rats chew … everything. They chew to get inside the building, they chew once they're inside the building, and they won't ever stop chewing. They CAN'T ever stop chewing. Their front teeth do not stop growing, so they need to chew in order to file them down and keep them to a manageable length.
In turn, this chewing can lead to damage to electric wires and cables, which can lead to fires. Plumbing and sewage works can be damaged, leading to further disease threats, bad smells, leaks, floods, and a lot of water damage. The chewing can also cause damage to the structures of buildings, with rats chewing concrete, drywall, wood, plastic, and many other materials.
In order to prevent rats from becoming a problem on your property, you will need to do two things.
Firstly, you will need to seal up your building so that rats (and mice) can't get inside. That means sealing up EVERY hole, and the only way that you will find every hole is by performing a full inspection on both the interior and exterior of the property.
Secondly, you will need to remove all food sources. It doesn't matter if you seal up the holes, rats will still hang around if there is a steady source of food … and they'll continue to try and find an entrance point (or make one) to stay safe and close to it.
Some professionals will use poisons to get rid of rats and other rodents, but that's not an approach that we advise you take. It can often lead to more problems than it actually solves, including a string of dead rat bodies in your home, in places you can't access, that decompose, start to smell, and don't get better until you physically remove them.
We use snap traps to kill and contain rat populations, and we use a lot of them. The more you can use, the faster your rat trapping and removal job will get done. You must ensure that you are placing in spots that are safe, though. If cats, dogs, kids, or other (vulnerable) humans can get to them and get trapped up in them, they're probably not in the safest place.
As well as trapping and removing rats, the infested building must be sealed up. Every single crack, crevice, hole, gap, or potential other entry point will need to be sealed to prevent future problems.
1 - Rats are thought to have originated in China, but can now be found on every continent with the exception of Antarctica.
2 - Females prefer to mate with males they haven't already mated with before, even after already mating with several different males.
3 - Rats are social animals and you'll never find just ONE in your home …
To learn more about rats, see: