In North America, the most common rats are the Black Rat (also known as the Roof Rat or House Rat) and the Norway Rat (also known as the Brown Rat, Water Rat, or Hanover Rat), each of which has differences in their behaviors, preferred habitats, and lifespans (to learn the details please read Roof Rats vs Norway Rats).
In this article, we’ll be answering the question, “How Long Do Rats Live?” and we’ll consider things you can do to help control a rat problem.
Remember that rats have two traits that make them incredibly hardy and therefore quite difficult to control. Those two traits are survivability and prolific breeding capacity. Because rats are so good at living in restricted conditions and because they propagate their species so well, they manage to stay alive and produce offspring even in the most challenging environments. Let’s take a closer look at each of the two most populous rat species in the United States and what their respective lifespans are. For information on the third and less populous rat species please see this article about Woodrats.
Lifespan of Black Rats
The Black Rat, sometimes known as a Palm Rat, has a lifespan that rarely exceeds 12 months. That’s right: the Black Rat doesn’t typically live longer than a single year. So, it might be tempting to think that any rat infestation you’re dealing with won’t ever last longer than that. However, remember that all rat species breed throughout the year, and a single rat couple can produce dozens of offspring in that time.
In fact, a single female Black Rat can have up to 15 litters in a single year! That’s a lot of baby-making. When you combine this statistic with the fact that a Black Rat reaches sexual maturity at only 3-4 months, you begin to realize just how efficient these animals are at furthering their lineage.
Lifespan of Norway Rats
In comparison with the Black Rat, the Norway Rat lives a much longer life—twice as long, in fact. The average lifespan of a Norway Rat, also known as a Sewer Rat, is right at two years. Keep in mind that this statistic is for Norway Rats that live in the wild; ones that are kept in domesticated captivity can live up to four years or even longer.
While there are many similarities between these two rat species, their lifespans are probably the most notable. They have similar tastes in food, with the exception being that the Norway Rat is a hunting rat, whereas the Black Rat will not hunt even when given the chance. It could be argued that the Norway Rat lives longer than the Black Rat on account of its dietary preferences, but there are many other factors that contribute to how long a rat will live.
Mortality Influencers
The two most critical aspects of a rat’s life—the things that will literally determine if the rat lives or dies—are water and food. If either the Black Rat or Norway Rat is able to secure reliable, consistent access to both a food and water source, chances are good that they’ll be able to live out their lives naturally. That is if another animal doesn’t eat them first.
Rat Predation
Another key determinant of a rat’s lifespan is whether or not the rat is consumed by predators. This is an especially common reason for rats to die prematurely. This is because the list of natural rat predators is quite long. Among the many animals that actively hunt and eat rats, some include:
- Snakes
- Birds of prey (hawks, owls, falcons, etc.)
- Coyotes and wolves
- Dogs
- Mountain lions
- Foxes
- Domestic cats
To thwart the threat of being eaten by other animals, rats have devised a keen ability to limit their exposure to the elements. This involves building intricate nests, foraging only during the nighttime, and being able to climb and swim efficiently.
When we combine the ready access to water and food with security from natural predators, we can be nearly assured that rats will live their longest lives possible.
Human Influence
Interestingly, human beings are a significant threat to rats, too. After all, we’ve only spent at least the past 15,000 years locked in an ongoing battle with rats. Rats have infiltrated shipping cargo, food stores, domiciles, and virtually anywhere humans have ever wanted to live, eat, or exist.
The Black Rat in particular has remained close by our side throughout the development of modern human history. In many cases, this rat has come to rely on humans just to live at all.
Granting our longstanding symbiosis with rats, it’s curious that we would be one of their biggest threats. But, it’s true, and with the recent increases we’ve seen in global temperatures (great news for rats), the rat war rages on even today.
Conclusion
The Black Rat has a lifespan of about 12 months, whereas the Norway Rat rarely ever lives longer than two years. Because these two rat species are so good at finding food, staying hidden, and avoiding detection, they manage to breed and increase the size of their colony remarkably quickly.
So, even though rats don’t live that long comparatively, their sheer volume in numbers is what keeps them in perpetual survival. As long as they have food, water, and a fairly hidden location to raise their offspring, rats will keep up their front in the ongoing human resistance against them.
Dealing with the ubiquitous spread of rats is something that can be achieved, however, with the right strategies. Learn more through the other resources found on this page.
