Selkirk Rex Age Calculator
Curly-coated breed founded on a 1987 spontaneous Montana mutation — a different gene from Cornish or Devon Rex. Both shorthaired and longhaired varieties exist; the curl is autosomal dominant. Stocky, heavy-boned, with a notably patient and even-tempered disposition. Selkirk Rexs typically weigh 10–16 lb (4.5–7.3 kg) at adulthood, with a typical indoor lifespan of 10–15 years.
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Using the standard AAFP/AAHA formula for a typical domestic cat. No breed required.
That's about the same as a human young adult.
Adult — Prime years; maintain weight and dental care.
Indoor cats live nearly 3× as long as outdoor cats on average.
How long do Selkirk Rexs live?
Indoor Selkirk Rexs typically live 10–15 years, with a median lifespan around 13 years. Lifestyle outweighs breed here: cats with outdoor access average around 6 years, and the causes are blunt ones — vehicles, predators, infectious disease, antifreeze. Indoors, weight is the first lever — BCS 4–5/9 — followed by dental disease, which accumulates silently from around age three, and hypertrophic cardiomyopathy (HCM), the concern most specific to this breed.
Origins of the Selkirk Rex
Founded in 1987 when a curly-coated kitten named Miss DePesto was born in a litter rescued by Persian breeder Jeri Newman in Sheridan, Montana. Newman recognized the curl as a novel autosomal-dominant mutation distinct from the Cornish and Devon Rex genes and began a breeding program using Persians, British Shorthairs, and Exotic Shorthairs as outcrosses. The breed name honours Newmans stepfather Selkirk. TICA championship recognition came in 1990; CFA followed in 2000. The dominant inheritance pattern means Selkirks can be outcrossed productively to other breeds and still produce curly-coated kittens in F1 generations - a fundamental difference from the recessive Cornish and Devon Rex genes. The Persian and British Shorthair outcrossing necessary to establish the breed introduced HCM and PKD risks the other Rex breeds largely escaped. Both shorthaired and longhaired varieties are recognized.
How a Selkirk Rex ages
If you map a Selkirk Rex's years to human chronology: 1 = ~15, 2 = ~24, 7 = 44, 12 = 64. The steady-state rate after age 2 is ~4 per year — slower than dogs because cats lack the size-driven cellular load variation that ranges dog aging across breeds.
Selkirk Rexs fall into the average feline lifespan band — 10–15 years for indoor cats with routine care. Outdoor-only access shortens this dramatically (cars, infection, predation); indoor-with-supervised-outdoor sits somewhere between. The breed has no major short-lifespan conformational pressure.
Selkirk Rex age conversion at a glance
| Selkirk Rex age | Human-equivalent |
|---|---|
| 1 year | 15 human years |
| 2 years | 24 human years |
| 5 years | 36 human years |
| 8 years | 48 human years |
| 12 years | 64 human years |
| 16 years | 80 human years |
Selkirk Rex weight chart
Adult weight for the Selkirk Rex typically falls between 10–16 lb (4.5–7.3 kg). Treat that as a band rather than a target. Body condition is what matters: ribs palpable under a thin fat layer, a visible waist from above, and a slight tuck when viewed from the side.
| Stage | Typical weight (Selkirk Rex) | What to watch |
|---|---|---|
| 8 weeks (kitten) | ~2.4–3.5 lb | Trajectory matters more than absolute weight. Weigh weekly. |
| 6 months | ~8.8–12.0 lb | Most cats at ~65% of adult weight by 6 months. |
| 12 months | ~13.6–16.0 lb | Most cats fully grown. Maine Coons and Ragdolls continue to ~3-4 years. |
| Adult (1y+) | 10–16 lb | Steady at BCS 4-5. If weight is climbing, measured meals will fix it faster than a diet food will. |
Stage weights are kitten-growth-curve approximations. Individual cats vary ±20% from these midpoints. For ideal weight + weight-loss math, use the ideal-weight calculator with current weight + BCS.
Care notes for Selkirk Rexs
- Hypertrophic cardiomyopathy (HCM) — outcrossing to Persians and British Shorthairs has introduced HCM risk; cardiac screening from age 3
- Polycystic kidney disease (PKD) — inherited from Persian outcross lines; DNA test before breeding
- Hip dysplasia — documented from British Shorthair outcross influence
- Coat care — the curly coat needs gentle weekly brushing; over-brushing breaks the curl pattern
- Brushing 2–3 times per week minimum to prevent mats.
- Dental health is the most under-diagnosed cat issue — annual cleanings from year 5 onward.
This is general breed-aware guidance. Always discuss specific concerns with your veterinarian.
Selkirk Rex life-stage milestones
AAFP's generic kitten/adult/senior bands miss the breed-specific timing windows. The stages below are calibrated for the Selkirk Rex:
- 8 weeks (kitten arrival): Verify HCM and PKD DNA test results from breeder - both inherited from Persian and British Shorthair outcross lines. Begin gentle coat handling. Standard vaccination protocol.
- 6 months (adolescence): Adult curly coat begins consolidating. Spay/neuter window. First cardiac auscultation baseline. First dental exam. Begin annual ultrasound screening for PKD if line history warrants.
- 1 year (young adult): Skeletally mature at 10-16 lb. Annual cardiac auscultation. Annual renal ultrasound if PKD line risk. Establish gentle coat care - over-brushing breaks the curl pattern.
- 3 years (prime adult): Annual cardiac auscultation - HCM peak diagnosis window from this age. PKD may declare on ultrasound. Continue gentle coat care. Dental disease accelerates.
- 11 years (mature/senior): Senior status. Twice-yearly cardiac auscultation. Annual senior bloodwork. PKD often progresses to chronic renal disease. Hip dysplasia (rare in cats but documented here) may declare.
- 15 years (geriatric): Selkirk Rex regularly reach 13-15 years on good cardiac and renal management. Cognitive dysfunction screening. Quality-of-life focus: cardiac maintenance, renal support, joint comfort.
Similar breeds you might be comparing
- Cymric — long-haired, 10–14 year lifespan
- Maine Coon — long-haired, 12–15 year lifespan
- Nebelung — long-haired, 11–16 year lifespan
Sources cited for the Selkirk Rex
- Cat Fanciers Association breed standard - Selkirk Rex.
- Gandolfi B, Alhaddad H, et al. "A dominant TRPV4 variant underlies osteochondrodysplasia in Scottish fold cats." Osteoarthritis and Cartilage, 2016. find this paper
- Lyons LA. "Feline genetics: clinical applications and genetic testing." Topics in Companion Animal Medicine, 2010. find this paper
- Selkirk Rex Breed Council - HCM and PKD screening guidelines.
- Lyons LA, Bailey SJ, et al. "Localization of a polycystic kidney disease gene in cats." Mammalian Genome, 2004. find this paper
Methodology: AAFP/AAHA Feline Life Stage formula. See the main cat age calculator for full methodology, indoor/outdoor lifespan model, and citations.
Selkirk Rex age FAQ
How long do Selkirk Rexs live?
Indoor Selkirk Rexs typically live 10–15 years, with a median lifespan around 13 years. Lifestyle outweighs breed here: cats with outdoor access average around 6 years, and the causes are blunt ones — vehicles, predators, infectious disease, antifreeze. Indoors, weight is the first lever — BCS 4–5/9 — followed by dental disease, which accumulates silently from around age three, and hypertrophic cardiomyopathy (HCM), the concern most specific to this breed.
How old is a 7-year-old Selkirk Rex in human years?
Using the AAFP/AAHA formula, a 7-year-old Selkirk Rex is approximately 44 human years old. Enter your cat's exact age and lifestyle above for a figure specific to your Selkirk Rex.
What is the typical lifespan of a Selkirk Rex?
Indoor Selkirk Rexs typically live 10–15 years. Selkirk Rexs fall into the average feline lifespan band — 10–15 years for indoor cats with routine care. Outdoor-only access shortens this dramatically (cars, infection, predation); indoor-with-supervised-outdoor sits somewhere between. The breed has no major short-lifespan conformational pressure.
When does a Selkirk Rex become a senior cat?
Most cats — including Selkirk Rexs — are considered senior starting at 11 years per AAFP guidelines. Mature stage (subtle age-related changes) begins around 7 years. Super-senior (geriatric) is 15+ years.
Are Selkirk Rexs good indoor-only cats?
Yes — almost all domestic cats, Selkirk Rexs included, do best indoors. Indoor cats average ~15 years against ~6 for outdoor-only, and with vertical space, play and a window perch the quality-of-life difference is negligible.
What is the difference between Selkirk Rex, Cornish Rex, and Devon Rex?
Three completely different mutations in three different genes, despite the shared "Rex" name. Cornish Rex (1950s Cornwall) is down-only and slim. Devon Rex (1959 Devonshire) is curlier still and elfin-faced. Selkirk Rex (1987 Montana) is the curliest and heaviest-built, and crucially the curl is dominant rather than recessive — Selkirks can be outcrossed to other breeds and still produce curly offspring in the first generation. Health profiles diverge accordingly: Selkirks carry Persian and British Shorthair risks (HCM, PKD) inherited through outcrossing that the other two Rex breeds largely do not.