The Black *Roof Rat (Rattus Rattus)

Also known as the black rat, Ship rat, or palm rat

Basic Identification

Distinguished by the Black fur, A Blunt pointier nose, smaller eyes, bigger Ears & a longer dark coloured tail. (Not that you were looking that close at the time!)

Signs of Roof Rats

Keys signs that tell you that they are Norway Rats;

• Droppings are often spindle-shaped with one end pointed
• Prefer to nest above the ground, in ceilings, rafters, trees similar to the palm
• No Tail-drag marks are found on dusty surfaces

Pointed Droppings

The Roof Rats' droppings are 1/2 -inch long with a twisted spindle shape to it, one end is blunt & the other pointed, and they often contain hairs.

You will find droppings where rats & mice are active, especially where they rest and feed.

A Roof rat produces about 50 droppings per day. You can get a quick estimate on the size of the infestation with the count.

Nest above the ground

Roof rats prefer to nest completely above the ground. In the ceilings, inside trees, anywhere that is off the ground, warm & dry.

No Tail-drag marks

The roof rat walks with its tail held off the ground, so when you are looking at rat footprints, there will not be any sign of a tail sweeping between them.

Roof Rat Foraging Facts

Rats & mice are generally nocturnal animals. They do however come out during the day when conditions require it

Conditions that bring rats out from the nest

• Resources such as Food & Water
• Human activity
• Finding a mate

Upon leaving the nest, they find pathways routes that provide as much concealment, protection & escape options as they can get while trying to find the shortest distance to food.

Food & Water

Necessary on all levels, rats are fixated on finding the next best supply of food & water. It does not have to be fresh, or even edible (in the human idea of food), it just has to be food.

They do however prefer oily/fatty food such as meat fat or oily fruit/veggies/nuts such as walnuts, avocado, and macadamia nuts.

Nuts, packed with great carbohydrates, oils, vitamins, and minerals are a great food supply to keep a rat healthy during winter.

On average, a Roof rat will forage will range up to 150ft, 50m in diameter from the nest. The range will only increase when one of the resources becomes scarce. They may consider shifting the nest location.

Human Activity

Like most animals, movement is often around the change of light, an hr before dawn or an hr after dusk, (When all military personnel in the field are in their fox holes, actively watching for enemy movement) rats do the same, waiting for it to be quiet

Rats will come out during the day whenever it is required. Ideally, when humans are not around, we know of many stories where the rats have become very brazen & not care about people at all.

Finding a mate

Since rats cannot effectively *swipe right, rats still need to find a mate the traditional way. They still need to find a suitable place to build a nest & this keeps them out while they inspect new territory.

(This happens to be the time when pre-baited stations get them) in the words of the late Eric Clapton song *I shot the sheriff, … Kill it before it grows.

Rats in a temple

Roof Rat Habits & Abilities

Being able to eliminate Roof rats effectively, as well as preventing them from getting inside buildings, requires a true knowledge and understanding of their biological abilities & habits.

• Roof rats can jump/leap about 35inches or 88cm
• Very good at Swimming
• Climbing vertical pipes, brick walls, etc
• A roof rat can handle being Dropped

Rats Leaping, Jumping, Climbing, Dropping & Swimming

A Roof rat will jump or leap across from a tree, fence line, pergola, drain, roof, etc without hesitation. A quick gauge that it can make the jump and woosh, it is gone. A roof rat is far better at jumping, climbing & leaping compared to the Norway rat

Rats Leaping - Black/Roof 32 inches 86cm

Rats Jumping - All rats approx 24 inches 60cm

Rats Climbing – All rats will climb anything they can grip onto incl vertical pipes < 4 inches 10cm

Rats Dropping – All rats can drop approx 50ft 15.5m without being hurt

Rats Swimming – All rats are very good swimmers, they can tread water for hours, and cover large distances. (Always a threat to our Island Bird Sanctuaries)

Roof Rats are Climbers. Occasionally they burrow when necessary yet they prefer to be elevated and above it all. They will climb an amazing assortment of objects, sooner considered impassable.

Leptospirosis or Wells Disease

Humans can get leptospirosis through direct contact with urine from infected animals or through water, soil, or food contaminated with their urine. It's most common in warm climates.

High fever, headache, bleeding, muscle pain, chills, red eyes, and vomiting are some symptoms.

Without treatment, leptospirosis can lead to kidney and liver damage and even death. Antibiotics clear the infection.

Active Exploration & Safety Protocols

All exploration & foraging activity is governed by the rat’s ability to sense its surroundings, since the roof rat prefers heights, its range of motion & path selection change as well. It will use trees, tops of fences, pergolas, retaining walls, drain pipes, etc

A rat will learn a path that is the safest possible. It will travel around structures and objects very quickly once the path is learned.

Because a rat’s sight is fairly below par, they rely more on what they hear, feel, smell, taste, and sense and regular behaviors.

A rat passes the food preferences to its young in the mother’s milk & crumbs lying around.

A rat will become familiar with noises, vibrations & people.

Neophobia – *Fear of new things in the environment. A built-in safety device

A keen sense of everything

All rats are fantastic at smelling, sensing vibrations, feeling & hearing faint noises. These abilities give the rat a huge advantage over most of their predators in the wild and around our homes.

What is Neophobia?

Neophobia-A type of *fear response to do with the uncertainty of whether a threat exists or not. A rat will map out the safest path to food or water and stick to it. They will travel this well-remembered path very quickly, only to stop when spooked or a new object is placed in the way.

They will not engage with the new object (ie bait station with bait inside) until their curiosity overtakes the possibility of a perceived threat.

Everything to do with a rat’s ability to survive is surrounded by threats (actual or perceived) & how they deal with them.

Rats Reproduction rates

In general, rats & mice have a high mortality rate, to prevent this from being detrimental to their survival, they have learned to multiply at a rapid rate!

Some quick figures to stun, silence & consider

Under normal conditions where all resources are available,

The Female Roof Rat is;

• Reproductively mature by 3 months
• She can have up to 9 litters per year
• Produce up to 56 young per year
• The young leave the nest after 30 days
• She will live about 1 year

The true reproduction matrix goes further to presume that under normal conditions where the available resources are high enough to support the population;

From the 56 young per year, once they also start to breed, the population explodes into the 1000s quite quickly.

To control Roof Rats, you will need to start thinking like a roof rat. They prefer to be up high where they find safety & warmth

You will need to consider what provides access to the roof? Where would be a good place to climb? Where would be a safe place to travel out of sight? What food and water sources are available?

What disturbances are around, such as animals, people, earthworks or machinery, predators & threats.

To catch a Roof Rat

You have options available such as trapping or baiting, toxic or non-toxic, kill or live traps, self-setting, or large bait capacity systems for unmonitored sites or situations.

Placement of the baits or traps is very important, as well as the number of baits or traps. Rats & mice prefer to feed on multiple stations, so have a good number of devices in place so all *Rodent pathways are covered.

We know all of this very well!

It is recommended that you seek good advice & get professional help from your local, qualified Pest Control company.