When researching having rats as pets, you’ll probably come across a lot of different terms for the different rat varieties – dumbo, standard, hooded, agouti, rex etc. But what do they all mean?
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Species vs variety
Fancy rats all belong to one species – Rattus norvegicus, also known as the “brown rat”. They have a tail roughly the same length as their body, a fairly blunt nose, with smallish eyes and ears. Their ears have short hairs on the back.
In the wild, R. norvegicus have one body shape, one type of coat, and mostly one color. However, genetic mutations have occurred naturally in the pet population and then been selected and bred for. As a result, fancy rats now come in a wide range of colours and coat textures and two ear positions. This is what we mean when we talk about fancy rat varieties – they are still all one species and can interbreed, but they have different looks.
The word variety can be used in different ways in the rat world:
- it can refer to whether the coat is smooth or curly,
- what shape the ears are,
- or what color the fur is.
As a result all rats belong to more than one variety – for example you could own a rex (coat type) dumbo (ear type) black (color) hooded (marking). Which category of variety is most important depends on whether you are entering a show or breeding, and where in the world you live – different fancy rat associations accept different varieties.
However, most of us just want to understand and know how to talk about our pets, so here are some of the most common types of pet rats.
This is the normal ear position seen in wild rats. The ears are to the sides of the top of the head and have an upright position when the rat is happy or alert. A stressed or angry rat can lie their ears back against their head. All rats were top-eared until the dumbo mutation was found.
Dumbos have rounder ears that are positioned lower down on the sides of the head so they stick out sideways. The head can look bigger and more domed, but that’s mostly a visual trick caused by the ear position.
There is a rumor that dumbo rats are tamer and live longer than top-ears. Unfortunately, it isn’t true – the only difference between a dumbo and a top-ear is their ear position. How tame a rat is, and how long it is likely to live depends on the family line they come from and how they are cared for, not what shape their ears are.
Dumbo and top-eared rats can be bred in any coat type or color variety.
Standard coated rats have a smooth glossy coat made of short straight hairs that lie flat to the body when the rat is well and calm. When the rat is angry or unwell they can fluff the coat up so it stands on end. Standard rats have long straight or gently curved whiskers which rats use to sense their surroundings.
Male and female fur can feel different – female rats have a softer silkier coat, while the male fur feels coarser and greasier. This is mainly due to the male hormones, which cause bucks to produce an orange grease from their skin (known as buck grease). The coat of neutered males often changes to be much softer.
The condition of the coat, how soft and shiny it is, also depends on diet. Poor diet can make the coat greasy or dull, dry or brittle. A healthy standard rat on a good diet will have a thick, soft and glossy coat.
Rexes have curly or crinkly fur and curled up whiskers. They feel soft and wooly to the touch (a lot of people nickname them sheep-rats because of the wooly feel and look). As rex rats get old they often get thinner fur or bald patches.
There are a lot of different genes that can cause rex fur around the world. When rats have two copies of a rex gene, they are called double rex. These rats have fur that is very tightly curled and is often quite sparse on the body – to the point that sometimes they look hairless. They have very tightly curled up whiskers, and care has to be taken that they don’t get eye problems from having very curly or absent eyelashes.
Another coat type that is very similar to double rex is patchwork. These rats have a very short patchy curly coat that sheds out and regrows in different places across the body.
Satin coated rats have fur that is unusually long and fine. They feel very soft to the touch, and the coat looks unusually shiny or even sparkly.
Hairless rats (Sphynx)
Hairless rats have been bred to be completely bald, although they often have some short curly fur around their whiskers, which are small and curly. The color of their skin will depend on the genes they have for fur color and markings. Pale colored hairless rats will be pink, while those with dark coloring will have black or grey areas of skin.
There are some concerns about the health of hairless rats. The lack of fur makes them more susceptible to cold, and means they have to burn more of their calories to keep warm. As a result, some hairless rats have a smaller than average body size. Like double rex rats, they can be prone to eye infections, as they have few eye lashes to keep dirt out of the eye socket.
There are several different genes that create hairless rats. At least one of them causes problems for the mother in lactating. Therefore, if you want to keep hairless rats it is very important to find a good breeder who has selected carefully for health and robustness. This may be difficult in some countries, as some associations, such as the UK’s National Fancy Rat Society have banned hairless rats from show.
A self rat is one whose fur is all a single color. The belly may be a paler shade of the main color, but there will be no white markings.
Marked rats have areas of white fur in their coat. There are a huge number of different markings standardised in the fancy rat world, and they can come in any coat type or ear position. Some of the most common are:
Berkshire: the rat has a white tummy socks, and often a white tail tip. If the white markings spread up the sides they are called over-marked.
Irish: a white triangle on the chest.
Hooded: the rat has a mostly white body, with the color restricted to the head, shoulders, and a stripe down the back. Quite often the stripe is broken up in splotches or is lopsided, which is called being mismarked.
Capped: the color is only seen on the head.
Blazed: the rat has a white blaze or wedge-shaped marking on the forehead.
Roan: the rat starts out colored but over time their coat moults out to be much paler and eventually white.
Black-eyed white: These are rats who have extreme levels of white markings, leaving them white furred but with dark eyes. Unfortunately, this extreme level of marking can cause health problems, as the precursors to the pigment cells have other roles in the body during development. Black eyed whites are prone to deafness and epilepsy, and banned from being shown in the UK.
What colors are possible in pet rats?
All the ear types, coat types and markings above can come in any color variety. There are a very wide range of colors possible. These are some of the most common:
Coat colors: non-agouti
The natural color for rats is agouti – a brown color made of hairs banded (or ticked) in black, grey, brown and orange. This color is caused by a dominant gene. However, some pet rats now don’t have this gene, meaning they are non-agouti, and each hair is the same single solid color. Common non-agouti colors are:
Black: non-agouti with no other genes to modify the colour. Fur is black but can include some white hairs (silvering) and they may get browner with age, illness or poor diet (rusting).
Beige (US) / buff (UK, Eur, Aus): a rich dark cream with ruby eyes.
Champagne: pale cream fur with pink eyes.
Mink: There are a lot of different mink genes around, but they all look greyish, with either warm or cold tones. They have black eyes.
Blue: non-agouti modified by a blue gene that is known, depending on country, as American blue, British blue, or Australian blue. It gives the coat a pure silver / blue color and black eyes.
Russian blue: non-agouti with a different type of blue gene. The Russian blue color is different to “blue” being usually darker and greyer. It’s marked by having heathering on the fur – each hair has a darker tip of the same color.
Coat colors: agouti-based
These colors have agouti-based coats, made up of ticked hairs.
Agouti: brown with black eyes.
Fawn (US) / topaz (UK, Eur, Aus): a rich ginger with ruby eyes.
Amber (US) / silver fawn (UK, Eur, Aus): a pale to bright ginger with pink eyes
Cinnamon: Agouti with the genes for mink. Looks a rich gingery brown and has black eyes.
Blue agouti / Russian blue agouti: Agouti with the relevant blue gene. The rats have black eyes and a coat that is brown but with blue / grey undertones.
Albino or pink-eyed white rats have a pair of recessive genes that mask other colors. So, they can have the genetic make-up to be agouti or black or mink etc, but the albino gene hides all that and leaves them with white fur and pink eyes.
Albino rats often have poor eyesight, as they have no pigment in their eyes to protect their retinas from damage. They adapt well to this, as rats rely more on smell and hearing than sight. However, it can make them jumpier, especially if they are from litters that were not well handled when young.
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Varieties and health
Most of the genes for varieties in rats don’t have any health effects. For example, a rex dumbo black hooded rat is no more or less likely to be healthy than a standard cinnamon berkshire top-eared rat.
However, there are some cases where genes that affect appearance can also affect health – we’ve already mentioned two with hairless rats and the black-eyed whites. Two groups of color genes can also have a negative effect.
The American / British blue gene, and some of the genes for ruby eyes have been linked to clotting disorders. This is because the cells that give rats their pigment are also related to precursors of blood cells. These rats don’t all have health problems, but it is very important to source them from reliable breeders who keep good health records.
Which variety of pet rats is best?
There’s no answer to that one! Personally, I love wild-type agouti rats, although as I only take in rescues my horde is a randomly mixed bag of whoever was in need. I’ve had everything from half-wild agouti to a one-eyed pink hairless. Variety doesn’t make one rat better, friendlier, or more likely to live long than another – those factors are all down to how well rats are bred, and how well they are looked after. If the variety of your rats matters to you then the best thing to do is get to know good breeders in your country who are working in those types.
Where to find out more?
This article has only covered the most common types of pet rats. There are several genetically more complex varieties (martens, siamese, roan etc), and rarer markings and coat types. Good websites to read more are the AFRMA website for the USA and Hawthorn rat varieties for the UK / Europe.