Male and female lifespan
Male Brachypelma hamorii are generally expected to live around 6–10 years, while females can live 20–30 years. The difference becomes most obvious after maturity.
If you buy a Mexican Red Knee as an older juvenile or adult, you may never know its exact age. Use the species range as a guide and keep your own dates from the point you acquire the spider.
Why females live longer
Female Brachypelma hamorii continue moulting after maturity, which allows them to remain healthy adult spiders for many years.
A male Mexican Red Knee eventually reaches an ultimate moult. After that point his remaining lifespan is usually much shorter than that of an adult female.
Growth and maturity
Mexican Red Knees are slow growers. Young spiders normally moult more often than large juveniles and adults, but the time taken to mature varies between individuals.
Do not try to estimate the exact age of Brachypelma hamorii from size alone. Feeding, temperature, sex and genetics all influence growth.
Feeding and temperature
A practical temperature range for Brachypelma hamorii is 20–25°C. Stable care and sensible feeding are more useful than trying to force rapid growth.
Keeping a Mexican Red Knee very heavily fed does not guarantee a longer life. Fresh water, suitable food, normal moults and stable enclosure conditions matter more.
Mature males
After the ultimate moult, a male Brachypelma hamorii may become more active around the enclosure and may eat less often than before maturity.
That change can be normal for a mature male Mexican Red Knee. Keep water available, continue offering food occasionally and make sure the enclosure remains secure.
Keeping records
Record moult dates for Brachypelma hamorii and keep suitable exuviae if you want to confirm sex. If the spider was not bought as a tiny sling, record the date acquired and approximate size instead of guessing an exact age.
Over time, those notes make the lifespan of a Mexican Red Knee easier to put into context and help show when growth and feeding patterns change.