This writeup will be centred primarily around the two most common rats. The black rat,Rattus Rattus and the brown rat, Rattus Norvegicus. For completeness, here is a list of all the genus "Rattus":

  • Rattus annandalei - Annandale's rat
  • Rattus argentiventer - Ricefield rat
  • Rattus bontanus - Lampobatang rat
  • Rattus exulans - Polynesian rat
  • Rattus feliceus - Spiny Seram, Pepina's rat
  • Rattus foramineus - Mekongga rat
  • Rattus fuscipes - Southern bush rat
  • Rattus hoffmanni - Hoffman's rat
  • Rattus leucopus - Southern spiny rat
  • Rattus marmosurus - Monkey-tailed rat
  • Rattus morotaiensis - Maluku prehensile-tailed rat
  • Rattus nitidus - Himalayan rat
  • Rattus norvegicus - Norway rat or Brown rat, Rat gris, Surmulot, Rat d'├ęgout
  • Rattus praetor - Large spiny rat
  • Rattus rattus - Black rat, House rat, Rat noir, Rat des Champs
  • Rattus sordidus - Canefield rat
  • Rattus steini - Small spiny rat
  • Rattus tanezumi - Asian house rat
  • Rattus tiomanicus - Malaysian rat
  • Rattus xanthurus - Yellow-tailed rat

Let's get physical

The rat belongs to the mouse-like family of rodents (in contrast to the squirrel-like rodents and the the cavy-like rodents). The brown rat weighs between 250-500g and it is 30-45cm long. The black rat, is usually between 35-45cm long but is much lighter than its cousin weighing between 100-300g.

Rats are great acrobats (the Black rat is more agile than the brown): they can leap up to 2.5 metres from standing and as much as much as 1 metre vertically.

Rats' worst sense is sight; they are colour blind. Despite this hangup, they can still judge distances well, which is useful when jumping. Rats have a very highly attuned sense of touch, and they are have long tactile hairs scattered about their body which help the rat negotiate tight spaces. Their sense of smell is also keen, and is integral to the rats breeding. A rat has good hearing, its range is 1,000-50,000Hz (in contrast to humans with a range of 20-20,000Hz and cats with a range of 100-60,000 Hz). A rat can taste about as well as a human can, and have an especial taste for sweets.


Rats originate from Asia, notably China, India and the Southeast Asian islands. The shipping trade assured the rat travelled, and Rattus Rattus, the black rat, arrived in Europe in the twelfth century. Rattus Norvegicus didn't arrive until the eighteenth century.

People began to keep rats at first for "sport" in the 1800s. Rat baiting involves pitting a terrier against a small swarm of rats to see how long it would take to kill all the rats. The albino rats were often spared, as were some of the other unusual pelted rats, and they were taken to shows or used for breeding. Rats also began to be used by scientists in the furtherment of science.

Rats used in scientific research travelled the Atlantic and in the late 19th Century they became a popular animal for experimentation; no doubt as a result of their rapid growth, tamability, intelligence, and because there were plenty of them. Their intelligence and trainability led to them eventually becoming accepted as pets (although some people will still cringe when you tell them what your pet is).

Rats and diseases

The Bubonic Plague is perhaps the most famous of rat-borne diseases. As most people are aware, it is not the rat that carries the disease, but the rat's fleas. The plague comes as a result of the bacteria, Yersinia pestis which is also fatal to rats.

Also on the list is another bacterial disease, Leptospirosis, or Weil's disease.

Colours, patterns, varieties etc

Whilst Rattus Norvegicus has naturally agouti in colour with a white or cream belly, domestic rats come in a variety of colours, shapes and sizes.

Standard: Bog-standard rat.
Rex: Curly hairs and even curly whiskers
Hairless: Self-exlanatory
Tailless: Also fairly self-explanatory
Satin: Longer and thinner hairs, giving them a fine coat.
Dumbo: Yes, these little ones have big round ears.

Rats come in a wide range of colours. Rats that consist of one uniform colour are known as 'selfs' or solid. The colours these rats come in are: beige, black, blue, blue-beige, champagne, chocolate, cocoa, Lilac, mink, platinum, Russian blue, sky blue, black-eyed white and finally pink-eyed white.

Sometimes rats may be of the same uniform colour, but the hairs themselves may be several banded colours, these include agouti, amber, blue agouti, chinchilla, cinnamon, cinnamon pearl, fawn, lynx and pearl.

Rats often have many combination of colours in their coats, in varying patterns. A rat that is one colour, but who's body is flecked with white hairs is known as a silvered rat. There are a few other recognized colour combinations:

Blue Point Siamese: Their body is ivory, with slate-blue nose, ears, feet, tail, and tail-root (these parts of the body are the rat's 'points'). Their eyes are red or ruby coloured.
Himalayan: White body with dark sepia points.
Seal point Siamese: You need to see a picture of one of these to get an understanding of their name. They have a brown body, with rich dark sepia points which blend gradually into the body.
Merle: These are any colour, but they are dotted with darker shades over their body so that they resemble a Merle dog.

Rats can come in patterns as well as colours; these marked, or spotted rats are quite popular, the most common of which is the hooded.

Hooded: Look how you'd expect them to look, they have white bodies, with a dark head and shoulders; this dark hair extends down their back.
Bareback: Bare back rats also have a hood, but are missing the dorsal stripe.
Capped rats: Also similer to the hooded rats, although the dark hair covers a much smaller area (not much past the ears).
Masked: Masked rats are white with a dark face (around the eyes and nose).
Dalmation: Spotty, can be varying colours, but black and white is the most common.
Blaze: Blazes have a wedge of white extending from their muzzle to their ears, tapering to a point at their ears.
Variegated: These have the white blaze on their forehead, with a variegated coat.
Berkshire: Berkshires have a coloured back, and a white underbelly, feet, tail and a white spot between their ears.
Irish: The Irish have any coloured coat, but their distinctiveness comes from having a small white patch on their underbelly, as well as tail with white tip to it.
English Irish: A strange name one might say. They are similar in looks to the Irish, the prime difference is that the patch on their underbelly is located between the front legs, and resembles an inverted equilateral triangle.

Aww, OK, now I want a pet rat!

Good. I must first tell you that rats are social creatures, so please, if you can, get at least two rats (and make sure they are the same sex!). Take into account were you live, do you have a cat (cats and rats can get along, but you have to have nerves of steel to let them play) or a python? (pythons and rats never get on, a cat thinks a rat is a plaything at a python a rat is dinner pure and simple), or young children? (tails are not a convenient way of 'leading' the rat to your bedroom) You'll need a home (may I recommend Martin's Cages?), food, toys, and a water dispenser before you should even think of acquiring a rat. It might also be wise to check around your local vets...make sure that one of them is confident and competent in dealing with small animals, ie., rats.

If you can, avoid buying rats from the local pet store. Most rat owners will sadly tell you the stories of rats being mass bred and if they aren't getting sold, they become snake food. It might be a convenient business idea, but its not a convenient business idea I like to support financially. Instead, buy from a proper private breeder. There are plenty of websites out there that will list your local breeder. If you are lucky, your pet shop will buy from a breeder themselves. If you have experience with rats you may also want to try local animal sanctuaries and rescue a rat. This is extremely rewarding.

Female rats tend to be more perky, whilst male rats tend to prefer lying around.


Rats are nesting animals, and they like to have some private space away from prying human eyes. Please avoid wood shavings(especially pine and cedar), whilst these are fine for other rodents, there is some evidence which links them to kidney and lung problems in rats. Also, you might want to avoid straw because this can irritate rattie eyes. A popular choice of bedding is Care Fresh; I recommend you search around the internet and in books for information about this subject. Opinions vary wildly so its best for you to make your own mind up about it.


Before you even think about breeding rats bare in mind that the average litter is between 6 and 12 pups and you should plan for the 'worst case' scenario...over 20 pups. If you can't house that many rats stop right now.

Sometimes you won't have a choice. I myself have picked up a girlie rat, only for her to strangely gain a lot of weight before dropping 8 babies underneath my bed one morning three weeks later. If this should happen to you, don't panic. Baby rats are adorable, really.

A female should not be bred before 4-5 months, and for her first pregnancy she should be no older than 6 months. Her gestation period will be 21-23 days, although this can sometimes be a little longer. Although the male may be left in the same cage during this time, once the big day draws near it is time to separate them. Oh yes, you will need two proper cages, since rats do not have any qualms about breeding with their mother or brothers...The father should be seperated before the birth because the mother will come onto heat within 24 hours of giving birth (I'd hate to be a female rat!), and she is quite capable of getting pregnant again. If you are breeding, don't be cruel to mom and give her a break of several weeks.

Baby rats are hairless, blind and deaf. They are even unable to defecate or urinate by they are completely dependent upon their mother. Female rats are excellent mothers, and are usually very you may notice her becoming more aggressive towards the end of the pregnancy and during the first week or two after it. Male rats make excellent fathers too, helping the mother-to-be get food and water, and defending her (my fingers (and even my lip!) will attest to that).

It takes about 10 days before hair starts to grow on the pups, and their eyes open soon afterwards. It takes less than a month before the babies can eat solids, although they will still feed from the mother from time to time.

Sickness and Death

Sick rats are no fun. Because of their size, their is often little that can be done for them except anti-biotics. Rats can get colds, develop pneumonia and develop cancer, amongst other ailments. Losing your rat will be painful, and is something you should think about before getting him/her. What arrangements do you have planned for them once they pass? A rat will live for 2-4 years on average, so these arrangements are not a distant eventuality.

Trust me, losing rats is not easy. They are full of personality and love and you never forget them. With that in mind, I'd like to dedicate this w/u to Justin, Jenner, Caligula, Castor, Pollux, Astaroth, Asmodeus, Nero Trillian and Nazumi.

Rats: A complete Pet Owner's Manual, Carol A. Himsel