At a glance the quick version
General figures for the domestic rat species from the MSD Veterinary Manual; the AFRMA and NFRS standards set no separate weight for this variety, which shares the standard rat body.
Coat and looks how to spot one
Rex (curly coat and curly whiskers); the body follows the standard fancy rat type
A Rex rat has the same sleek, long body as any fancy rat, but its fur is curled or wavy all over, a little less so on the belly, and it has very few long guard hairs, so the coat feels soft rather than wiry. Even the whiskers are kinked and usually shorter than a smooth-coated rat's. Babies show the tightest curls; after the first moult at around six to seven weeks most settle into a softer wave. Males tend to carry the best coats.68197
Personality what they are like
The rex gene changes the coat, not the character, so a Rex rat has the same friendly, curious nature as other fancy rats. Well-socialised rats bond closely with their keepers, enjoy being handled and learn tricks readily. AFRMA breeders describe some rex lines as very sweet.751
Daily activity how busy a day looks
Just as lively as any fancy rat. Most active from dusk into the night, they need daily supervised time outside the cage plus climbing, foraging toys and short training sessions to keep busy and content.510
Grooming and care the hands-on bits
Rats keep themselves and each other clean, so the curly coat needs no brushing or bathing. Expect the coat to change through the rat's life: tight baby curls relax after the first moult and the coat becomes lighter as the rat matures, which is normal for the variety. Regular spot-cleaning of the cage and daily gentle handling cover the rest.1911
Home where they are happiest
The same set-up as any pet rat: the biggest multi-level cage you can fit, with shelves, ropes, ladders, hammocks and hideouts, dust-free bedding such as cellulose or shredded paper, and a quiet spot kept at roughly 19-23 C, out of direct sun and draughts.103
Food basics what goes in the bowl
A complete rat nugget or pellet as the daily staple, with small portions of vegetables, a little fruit, grains and cooked egg counted into the ration. Keep sugary or fatty bits for training rewards, scatter some food to encourage foraging, and provide fresh water from a bottle at all times.11
Company who they like around
A very sociable animal that should share its home with at least one other rat, in a same-sex pair or small group or a neutered mixed pair, and enjoys daily time with its people.57
The story where it all began
The curly rex coat is known in several pet species, and in rats it was bred in England in 1976. The AFRMA credits geneticist Roy Robinson with the English rex rats, and the newly founded National Fancy Rat Society standardised the variety that same year, showing curly rats at the 1976 Bradford Championship Show, the society's first show appearance. Rex rats then spread to the United States through pet shops, universities and private keepers. Karen Robbins got her first rex, an agouti Irish male, from Mary Sheridan in 1983 and bred her first rex litter on 22 September 1983, and Mary Sheridan exhibited two rexes at a show on 8 October 1983. On 29 November 1983 a shipment of 32 rats arrived from England, including three rexes, which helped build up American lines. Rex is now one of the seven varieties in the AFRMA standard. In 2010 Japanese researchers traced the rat rex coat to a small change in the Krt71 keratin gene, the same gene involved in the curly coat of the Devon Rex cat.1281213
Fun facts for the dinner table
- 1
Rex rats don't just have curly fur, their whiskers are curly too.6
- 2
The rex trait is dominant: pair a rex with a smooth-coated rat and roughly half the babies will have curly coats.1
- 3
A well-curled pink-eyed white Rex has been compared to a tiny sheep.1
- 4
Rex rats appeared at the 1976 Bradford Championship Show, the very first show the National Fancy Rat Society took part in.2
- 5
Baby rexes have their tightest curls; after the first moult at about six to seven weeks most coats relax into soft waves.1
- 6
The rat rex coat comes from a change in the Krt71 gene, the same keratin gene linked to the curly coat of Devon Rex cats.12
- 7
The NFRS standard notes that females are given a little leeway for curl, since males usually grow the better rex coat.6
Recognised by the official bits
- National Fancy Rat Society (UK)
- Standardised in 1976 and shown at the Bradford Championship Show that year. Listed among the NFRS Rex/Dumbo varieties; the standard asks for an evenly dense, evenly curled coat with few long guard hairs and curly whiskers, in any recognised colour or pattern.6
- American Fancy Rat and Mouse Association (AFRMA)
- One of the seven recognised AFRMA rat varieties, shown in any recognised colour or marking.8
- Rat and Mouse Club of America (RMCA)
- Has its own Rex standard calling for an evenly dense coat that is not overly harsh, with curly whiskers counted as normal.14
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Rex Rat. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- Spot cleanevery day
- Full cleanevery week
- Play timeAt least an hour out of the cageevery day
- Nails checkevery 3 weeks
- Vet check-upevery year
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Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.
- AFRMA - Rex Rats afrma.orgused for origin, history, genetics, coat changes, fun facts
- National Fancy Rat Society - Wikipedia en.wikipedia.orgused for 1976 founding and first show with rex rats
- MSD Veterinary Manual - Description and Physical Characteristics of Rats msdvetmanual.comused for weight, lifespan, room temperature
- AFRMA Rat Standards afrma.orgused for body length
- RSPCA - Rats rspca.org.ukused for lifespan, temperament, social and activity needs
- NFRS - Rex/Dumbo Varieties nfrs.orgused for recognition, standard, coat, whiskers
- Fancy rat - Wikipedia en.wikipedia.orgused for coat description, temperament, colours, social needs
- AFRMA Fancy Rats - Varieties afrma.orgused for recognition, standard coat description, colours
- AFRMA - Rex and Double Rex Rats afrma.orgused for coat and whiskers, moulting, breeding
- RSPCA - Rat environment rspca.org.ukused for housing
- RSPCA - Rat diet rspca.org.ukused for diet, care routine
- Identification of the Rat Rex Mutation as a 7-bp Deletion at Splicing Acceptor Site of the Krt71 Gene (Kuramoto et al., 2010) researchgate.netused for genetics
- The naked truth: Sphynx and Devon Rex cat breed mutations in KRT71 link.springer.comused for Devon Rex cat link
- RMCA Rat Standards: Rex rmca.orgused for recognition
Checked 2026-09-30. Text is written in our own words from these sources.