Roof Rat or Norway Rat: How to Tell Which One You Have

Roof rats are slim, climb well and nest high in attics and trees, while Norway rats are heavier, burrow in the ground and get in at foundation level. The quickest way to tell them apart is where you find the signs: up high usually means roof rat, down low usually means Norway rat.

In Arcadia, roof rats are the most common rat by far, especially on the tree-heavy north side. Norway rats show up more around foundations, drains and commercial areas in the south. Below we walk through size, tails, droppings and habits so you can figure out which one you have, and why it matters for how you get rid of it.

How do you tell a roof rat from a Norway rat?

A roof rat has a tail longer than its head and body combined, large ears and a pointed nose, while a Norway rat has a shorter tail, small ears and a blunt nose. Roof rats look sleek. Norway rats look stocky.

A roof rat, also called a black rat or fruit rat, is a climbing rodent that nests above ground in trees, attics and wall voids. A Norway rat, also called a brown rat or sewer rat, is a burrowing rodent that nests in the ground, under slabs and in crawl spaces. Both are common in Los Angeles County, but they behave very differently.

Size, tail and face

Roof rats and Norway rats differ enough in build that you can often tell them apart from a quick look or a trail camera photo.

• Roof rat: body about 6 to 8 inches, tail 7 to 10 inches, weight around 5 to 9 ounces, large ears that can cover the eyes when pulled forward, pointed nose, dark gray to black or brown fur.
• Norway rat: body about 7 to 10 inches, tail 6 to 8 inches, weight often 10 to 17 ounces, small ears, blunt nose, coarse brown fur with a lighter belly.

The tail is the easiest tell. If the tail is longer than the body, it's a roof rat. If it's shorter, it's almost certainly a Norway rat.

What do their droppings look like?

Roof rat droppings are about 1/2 inch long with pointed ends, while Norway rat droppings are about 3/4 inch long with blunt, capsule-shaped ends. Mouse droppings, for comparison, are about 1/8 to 1/4 inch, like grains of rice.

Where you find droppings matters as much as their shape. Roof rat droppings show up in attics, on top of insulation, along rafters, on shelves and in garages near the ceiling. Norway rat droppings show up along walls at floor level, in crawl spaces, under sinks and near burrows outside.

Fresh droppings are dark and soft. Older ones are dry, gray and crumble. If you see fresh droppings, the rats are active now.

Where each rat lives in Arcadia

Roof rats dominate most of Arcadia because of the city's mature oak, citrus and avocado trees, while Norway rats are more common near foundations, drains and commercial trash areas on the south side.

Roof rats

UC IPM notes roof rats can travel up to 300 feet a night and favor citrus and avocados. In neighborhoods with continuous canopy, they move from tree to tree to roof without touching the ground. That's why Rodent Control in Santa Anita Oaks is almost entirely roof rat work: the old oaks reach right over the rooftops.

Signs of roof rats include scratching in the ceiling at night, hollowed oranges left hanging on the tree, rats running along fences and power lines at dusk, and grease marks along rafters.

Norway rats

Norway rats prefer the ground. They dig burrows 2 to 4 inches wide along foundations, garage slabs, fences and under sheds, usually near water and food. On the south side of the city, Rodent Control in South Arcadia involves a lot more burrow trapping and slab sealing than anywhere up north.

Signs of Norway rats include burrows with fresh dirt, droppings along walls at floor level, gnawed door bottoms and noise under the floor in raised-foundation homes.

Why the difference changes the fix

Knowing whether you have roof rats or Norway rats in Arcadia changes where traps go and which entry points get sealed. Treating the wrong rat wastes time and money.

For roof rats, we put traps in the attic along runways and seal roof returns, gable vents, ridge vents and fascia gaps. We also mark tree limbs within 3 feet of the roof for trimming. Our Rat Control in Arcadia starts on the roof for that reason.

For Norway rats, we trap at burrows and along ground-level runways, then seal slab gaps, garage door bottoms, foundation vents and pipe penetrations from the crawl space. Removing pet food, compost and water leaks outside matters more with Norway rats because they live closer to those sources.

Some homes have both. A raised-foundation house under an oak tree can have roof rats in the attic and Norway rats in the crawl space at the same time. Full Rodent Exclusion and Proofing in Arcadia covers both levels so neither can get back in.

Common mistakes in identifying rats

Arcadia homeowners often misidentify rats in ways that send them down the wrong path. Watch out for these.

• Assuming any rat in the garage is a Norway rat. Roof rats nest in garages too, especially up in rafters and storage.
• Calling a young rat a mouse. Young rats have big heads and feet for their bodies. Mice have small heads and big ears.
• Setting ground traps for roof rats. Roof rats travel high. Traps on the floor catch fewer of them.
• Sealing only the roof when Norway rats are the problem. They come in low, through slabs and vents.

When to call a professional

Call a professional for rat identification in Arcadia if you're hearing rats but can't find where they're getting in, or if you've trapped a few and they keep coming. Ongoing activity means open entry points.

Rodent Control Arcadia inspects the roof, attic, garage and crawl space, identifies the species and sets traps where that species actually travels. If you're in the west half of the city, our Rodent Control in Arcadia 91007 team sees both types regularly, often on the same property.

Frequently Asked Questions

The questions below cover what Arcadia homeowners ask most about telling roof rats and Norway rats apart.

Get help with Rodent Control in Arcadia

Not sure which rat you have? Call us and we'll inspect, identify the species and set up the right plan.