Roof Rat, Rattus rattus

DIET: Extremely varied.

PREDATORS: Owls, hawks, coyotes, foxes, snakes, cats, raccoons, other rats, etc.

HABITAT/RANGE: Anywhere with cover and a food source.  Along with the West and East Coasts of the US, also found in Europe, Asia, and lower Africa.

CONSERVATION STATUS: Least concern

WHERE TO OBSERVE IN SB:  In bushes and vine-covered fences almost anywhere, including backyards and parks.

The roof rat (also called the black rat) is a common backyard rodent across the country, especially in coastal regions like Santa Barbara.  These rats are good climbers and are often seen scampering along tree branches or fence rails.

Appearance

Roof rats are 6 to 8 inches long excluding their tail, which is at least as long.  They have beady eyes, large ears, and pointed noses.  Their fur can be grey or brown. 

Ecological Roles

The food sources of roof rats are numerous and varied.  They can eat almost anything we can, along with birdseed, bird eggs, pet food, and even other rats.  They choose their food sources based on what is available. Wherever there is food, there are rats, including cities, backyards, and more natural areas.  In backyards, fruit trees are a common food source.

Roof rats are an important food source for owls, hawks, snakes, coyotes, foxes, and many other animals.  

Behavior

Roof rats are mainly nocturnal, although they may be seen during the day if disturbed, hungry, or sick, or if there is a daytime food source.  They are agile climbers and often climb to find food, such as fruit from trees. Their nests are usually located above the ground, such as in bushes or crevices in structures.

How to Observe Roof Rats

You likely don't need to go much further than your own yard or neighborhood to see a roof rat, as they are so ubiquitous.  Evening is the best time to find them, since rats are generally nocturnal.  Fencelines (especially those covered in vines or other greenery), fruiting trees or vines, and hedges are good places to see them.

Avoiding Conflict with Roof Rats and Other Rodents

Like other wild animals, having a few rats around is not a problem in itself.  In a healthy ecosystem, rodents provide a food source for larger animals, and these predators keep the rodent population from getting out of control.  The problem occurs when rodents overpopulate due to too much food and not enough predators, or when they cause property damage or health risks by living too close to people (like in someone's house or garage).

Instead of trying to eliminate all rodents from your property, focus on avoiding the specific problems they are causing.  If your yard is overrun with rats, this means there is an imbalance in the ecosystem.  Most likely, there is a steady supply of both food (such as a fruit tree or a birdfeeder) and cover from predators (such as thick vegetation or a woodpile).  If rats can eat all they want and stay safe from predators, they will overpopulate.  This issue can be resolved with habitat modification.  Another common problem is for rats to find their way into a home or other structure, and the solution is to seal all potential entry points and remove the remaining rodents. 

 

For more information on solving a rodent problem, see Controlling Rats and Mice.  Or if the rodent problem is in a chicken coop, see Building and Maintaining Wildlife-Proof Chicken Coops.

Image credits: Roof rat- Alex O'Neal, Creative Commons.