A castor rex rabbit is a Rex with a rich chestnut coat tipped in black, the original color of the breed. Adult show-standard bucks weigh roughly 7.5 to 9.5 pounds and does 8 to 10.5 pounds. The fur is the main attraction: short, dense and springy rather than soft and silky.
That fur also brings the one care issue every owner should know about. Rex rabbits have a reputation for thin protection on their feet, so flooring and regular foot checks matter more than they do with most breeds.
This guide covers how to recognize a castor rex, how it differs from the Mini Rex, what its temperament is like, and how to look after it.
What is a castor rex rabbit?
“Castor rex” refers to the castor color variety of the Rex breed. It is one of 16 Rex varieties recognized by the American Rabbit Breeders Association (ARBA), alongside colors such as black, blue, chocolate, lilac and white.
The name has a history. According to the National Rex Rabbit Club, the first rabbits with this fur were shown to Abbé Amédée Gillet, a priest in the south of France, who called them the king’s rabbits (rex is Latin for king). Castor was the first variety to be perfected, and the breed was originally called Castorrex. After the breed reached the United States around 1924, breeders developed more colors and the “Castor” part dropped from the breed name.
The variety is named for its resemblance to beaver pelts. Castor comes from the Greek word for beaver.
Castor rex color and coat
The castor color is a rich chestnut brown with black tipping. The undercolor is described as slate blue. Under the ARBA Rex standard, toenails on castor rabbits should be dark.
The coat is judged as closely as the color. Fur counts for 40 points in the ARBA Rex standard, color for only 10. The standard calls for:
- Extremely dense fur between 1/2 and 7/8 inch long, with 5/8 inch as the ideal
- Fur that stands upright and feels uniformly smooth over the whole body
- A springy resistance when you press it, not a soft or silky feel
- Plentiful guard hairs that do not stick out noticeably
In practice, that means a castor rex should feel like firm plush. If the coat feels flat, silky or wavy, a show judge would count it as a fault.
Castor rex rabbit size and weight
The standard Rex is a medium-sized, meat-type rabbit with a balanced, well-rounded body. These are the ARBA senior class weights, as listed on a breeder site reproducing the standard:
| Class (6 months and older) | Weight range | Ideal weight |
|---|---|---|
| Senior buck | 7.5–9.5 lb | 8 lb |
| Senior doe | 8.0–10.5 lb | 9 lb |
Some pet-care websites state that Rex rabbits reach 12 pounds. That is above the show standard, so treat it as an outlier. Because ARBA revises its Standard of Perfection periodically, check the current edition at arba.net before relying on these numbers for showing.
Castor rex vs castor Mini Rex
People often mix these up because both come in castor and both have rex fur. The Mini Rex is a separate, smaller breed developed later by crossing Rex rabbits with dwarf breeds.
| Castor Rex | Castor Mini Rex | |
|---|---|---|
| Breed | Rex (standard) | Mini Rex |
| Adult weight | About 7.5–10.5 lb for show-standard adults | Maximum about 4.5 lb |
| Fur | Rex fur | Rex fur |
| Space and food needs | Larger rabbit, needs more room | Smaller rabbit |
If a listing says “castor rex” without a weight, ask the breeder which breed it is. A rabbit weighing under 5 pounds as an adult is not a standard Rex.
Temperament and suitability as a pet
Rex rabbits are commonly described as calm and intelligent, and does are sometimes said to be good mothers. Those are general descriptions, not guarantees. Individual rabbits vary, and handling from a young age makes a bigger difference than breed.
A castor rex can suit you if you:
- Have room for a medium-sized rabbit
- Can provide soft resting surfaces and check its feet every week
- Want a rabbit that is sturdy and meaty rather than tiny and delicate
It is a weaker fit if you want a very small rabbit, or if you cannot commit to the foot care described below.
Caring for a castor rex rabbit
Flooring and sore hocks
Sore hocks (ulcerative pododermatitis) is a painful condition where the sole of the foot becomes raw and inflamed. The House Rabbit Society notes that Rex breeds have very fine fur that does not hold up well to friction, and that they seem particularly prone to the problem.
What helps:
- Give the rabbit soft, solid resting areas, such as a thick layer of bedding or a washable mat
- Avoid bare, unsupported wire floors
- Keep toenails trimmed, since long nails shift weight onto the heels
- Look at the back feet weekly. Fur loss or pinkness on the hocks is the signal to act
If you see open sores, see a rabbit-experienced vet. Wrapping an open sore without treatment can lead to serious infection.
Grooming and molting
The short coat needs little routine brushing. Expect more grooming during a molt, when loose fur builds up. Use the weekly check to look at teeth and nails as well.
Diet and housing basics
Like all rabbits, a castor rex needs unlimited hay, fresh water, and a measured amount of pellets and vegetables. Your vet can set quantities for your rabbit’s weight and age. Rabbits are social, and many do better with a bonded companion, though bonding should be done carefully.
What the breed is used for
The ARBA standard describes the Rex as a meat-type body with a fur coat, and the breed is raised for showing, fur and meat, as well as kept as a pet. If you are comparing Rex with other farm breeds, see our guide to the best meat rabbits for farming.
Checklist before you get one
- Ask the breeder for the rabbit’s age, weight and pedigree
- Check the back feet for fur loss, redness or sores
- Feel the coat: it should be dense and springy, not flat or silky
- Look for dark toenails and the chestnut-and-black color
- Confirm you can offer a soft, solid resting surface
- Find a rabbit-savvy vet before you bring the rabbit home
Breeders who show Rex rabbits can often be found through the National Rex Rabbit Club, which also publishes variety information.
Conclusion
The castor rex rabbit is the original Rex color: chestnut brown, black-tipped, and covered in dense plush fur. It is a medium-sized, usually calm rabbit that rewards owners who prepare for its main weakness, thin foot protection. Choose soft flooring, check the feet weekly, and confirm with the breeder whether you are getting a standard Rex or a Mini Rex.
FAQ
Is a castor rex the same as a Rex rabbit? Not exactly. Castor is one color variety within the Rex breed. All castor rex rabbits are Rex, but not all Rex rabbits are castor.
How big does a castor rex rabbit get? Under the ARBA standard, adult bucks are 7.5 to 9.5 pounds and does 8 to 10.5 pounds. Verify against the current Standard of Perfection.
Are Rex rabbits good pets? Many owners find them calm and friendly, but individual temperament varies. Their sensitivity to foot problems means they need softer flooring than some other breeds.
What is the difference between a castor rex and a castor Mini Rex? Size. The Mini Rex is a separate, smaller breed with a maximum weight of about 4.5 pounds, while the standard Rex is roughly twice that.
