Mexican Red-Knee Tarantulas as Pets: Lifespan, Size and Care Info

What You Need to Know About Mexican Red-Knee Tarantulas as Pets

Most people would not think of having a spider as a pet, let alone a tarantula. With spiders being one of the most feared animals and arachnophobia being one of the most well-known and prevalent phobias out there, many people wouldn’t think of adopting these large spiders as their pets. However, many people, especially spider enthusiasts, are adopting as pets Mexican Red Knee Tarantulas.

The Mexican Red Knee Tarantula is a species of spider that is native to the Western parts of Mexico along the Pacific Coast. The Mexican Red Knee Tarantula is a docile species that hardly bites. Due to this, it has gained popularity among spider owners. Both the Brachypelmahamorii and the brachypelmasmithi are referred to under the umbrella term of Mexican Red Knee Tarantula, but both exhibit the trademark red coloration on their legs, giving them their name. Compared to other species of tarantula, the Mexican Red Knee is larger in size and, like other species, enjoys a long lifespan.

If you are curious about this tarantula species and are even considering getting one as a pet, the following information is a must-know read for you. Continue on to learn about this spider’s behavior, eating habits, lifespan, and care requirements.

Do Mexican Red Knee Tarantulas Make Good Pets?

The Mexican Red Knee Tarantula has enjoyed a rise in popularity among pet owners, more specifically among spider enthusiasts. This tarantula exhibits a docile demeanor and hardly ever bites, which lends itself to being a great first pet for those looking to get into owning tarantulas.

This spider can also be picked up and handled gently often without becoming stressed or irritated. It also moves rather slow and does not require elaborate care. All of these factors play into making the Mexican Red Knee Tarantula a great pet for those interested in owning a spider.

How Long Do Red Knee Tarantulas Live?

Like most tarantulas, the Mexican Red Knee enjoys quite the long lifespan. However, the lifespan varies widely based on the gender of the spider.

Female Mexican Red Knees can live for as long as 20 to 30 years. Males, on the other hand, tend to only live 5 to 10 years.

How Big Does a Mexican Red Knee Tarantula Get?

The Mexican Red Knee Tarantula can vary in size, anywhere from 4 to 7 inches (10 to 18 centimeters) and weigh around 15 to 17 grams (0.5 to 0.6 ounces).

Like their lifespan, the size of the Mexican Red Knee differs based on their gender. The female tarantulas tend to be bigger in size.

Mexican Red Knee Tarantula Cost

Depending on where you buy your tarantula from, purchasing your Mexican Red Knee can cost anywhere from $20 to $200 USD. This is just the initial cost, though. You should also consider the rest of the financial investment preparing to care for a pet entails.

You will need to buy a terrarium and environmental amenities to make the terrarium suitable for your spider. You should also consider the ongoing costs of owning a pet. Food and water, healthcare, and many other costs can come up.

Due to their popularity, Mexican Red Knee Tarantulas are pretty easy to find in pet stores, online shops, and breeders. It is recommended to buy them from breeders, though.

Breeders are more experienced in raising pets like this and often have experience and training in caring for tarantulas and practicing proper socializing and husbandry techniques. This can assure the good health of your pet and a more enjoyable experience of owning this spider.

Mexican Red Knee Tarantula Color

The Mexican Red Knee Tarantula earns its name from a unique coloration that sets it apart from other species of tarantula. Like many other tarantulas, the Mexican Red Knee has a dark body, usually black or dark brown. However, its distinguishing feature is a bright red streak on its legs, thus giving it the name of “Red Knee.”

As mentioned before, the classification “Mexican Red Knee Tarantula” actually encompasses two separate species of tarantula: the Brachypelmahamorii and the Brachypelmasmithi. Scientists have noted that these two species exhibit slightly different colorations and body shapes at times, they both have the bright red coloration on their legs, earning them both their catch-all name.

Are Red Knee Tarantulas Poisonous?

The Mexican Red Knee Tarantula, like many other tarantulas, is poisonous. However, its venom is a mild one, making it not that dangerous to have as a pet. If you do come in contact with the Mexican Red Knee’s venom, at most you will have symptoms similar to that of a bee sting: redness and swelling around the affected area. These effects typically last anywhere from a day to 72 hours.

The only danger posed from the venom of a Mexican Red Knee Tarantula is if someone has an allergic reaction to them. If this happens, you should call a doctor right away to seek treatment.

Are Mexican Red Knee Tarantulas Aggressive?

The Mexican Red Knee Tarantula is known among spider owners to be one of the most calm and docile spiders in the trade.

The aggression levels can vary depending on the gender, however. Females are known to be the more aggressive of the two, which helps them have a longer lifespan. Females have also been known to be aggressive towards the males after mating.

They can also become aggressive towards rogue or unfamiliar spiders. This is often in response to what they see to be a threat or encroachment on their territory.

When a Mexican Red Knee Tarantula feels threatened and may become aggressive, it rears up to display its fangs to the perceived threat. Another defense mechanism Mexican Red Knees have is to propel barbed hairs laced with their venom from their abdomen. If you notice any of these behaviors, it is best to give your tarantula some time alone to cool off.

All this being said, Mexican Red Knee Tarantulas are widely known for being calm and docile most of the time. They hardly ever bite or attack anyone or anything unprovoked.

How Long Does It Take a Mexican Red Knee Tarantula to Mature?

After a spiderling hatches from the egg sac, it typically spends about two weeks in the burrow. After this time, it leaves its home to be independent and find its own way in life. This is, on average, around twelve to sixteen days of age.

It isn’t until the male spiders reach about 4 years of age that they become sexually mature. At this age, they have a regular cycle of molting set up. At the 20th instar, which is the stage between molts, the males become fully sexually mature and are ready to engage the female in their mating ritual.

As with many tratits and characteristics with this breed of spider, the female and male Mexican Red Knee Tarantulas mature at different ages. The females, on average, mature about 2 to 3 years after the males. By this time, the female tarantulas are around 6 or 7 years old.

When both genders reach their full maturation age, they are ready to engage in their mating ritual. In this mating ritual, the male uses his front legs to lock the jaws of the female open. He positions himself behind her and bends her backwards. He deposits the sperm into an opening on the female’s abdomen and quickly flees. The males take their leave quickly to avoid the aggression that the females typically have after mating.

When the male is gone, the female carries the eggs in her abdomen until the spring. When spring comes, the female weaves a silk mat, deposits the eggs on it, and covers them in a sticky liquid that contains the male’s sperm.

After the eggs are fertilized, they hatch in about one to three months, giving birth to new spiderlings. The spiderlings stay in the egg sac that the female carries for another three weeks after hatching.

How Long Does It Take for a Mexican Red Knee to Molt?

When a Mexican Red Knee Tarantula is first born, it molts every two weeks. This frequency lasts for about the first four months of its life. After that, the frequency of molting decreases.

Once male Mexican Red Knees reach sexual maturity at age four or five, their molting ceases altogether. Females, on the other hand, continue to molt past their sexual maturation age, around age six or seven.

The purpose of molting for Mexican Red Knee Tarantulas is mainly healthcare. Molting sheds their old layer of skin which removes any dangerous, external parasites and fungus. This molting process also provides the Mexican Red Knee with a new, fresh set of undamaged sensory and protective hairs.

How Long Can a Mexican Red Knee Tarantula Go Without Food?

Mexican Red Knee Tarantulas don’t need to eat all that frequently. Usually, a Mexican Red Knee will eat once every week. In the wild, this number may vary to be more or less depending how much foo they can find.

For your pet, though, you should be feeding your Mexican Red Knee at least once a week up to three times a week if need be.

How to Handle a Mexican Red Knee Tarantula

Mexican Red Knee Tarantulas are slow moving, docile creatures, which lends them to being handled easily. Many Mexican Red Knee owners have noted that it is easy to handle these spiders often while causing no stress to the animal.

However, you must handle them with care. These spiders have a delicate exoskeleton system. If handle too roughly or dropped, even from a short height, this can result in serious injury to your Mexican Red Knee or even death.

When handling your pet, make sure you are always seated or have them low to the ground on a carpeted or soft area. Keep your hands open and let the tarantula sit or move around on your open palm. Never close your hand around your spider as this may come off to them as a threat.

If you are not comfortable handling your Mexican Red Knee Tarantula with your bare hands, you can use gloves or other instruments. Always keep in mind to be gentle. The best alternative to handling your tarantula with your hand is to use a cup or container.

Place the cup or container near the spider and let it walk into it, or gently scoop it up. Once you are done with whatever you needed the spider out of the way for, place the container back in the spider’s habitat and let it wander out on its own or gently tip it out.

There are signs you should watch out for when your spider becomes agitated so you can avoid injuries, both to you and to your pet. If your Mexican Red Knee feels threatened, it will rear up on its hind legs and bare its fangs.

This is often a precursor to a bite attempt. It may also flick barbed hairs from its abdomen as a way to transfer its venom. If you notice these behaviors, wait a little time before trying to handle your pet again.

Care of Mexican Red Knee Tarantulas

Temperament of Mexican red knee tarantulas

Mexican Red Knee Tarantulas are known for being calm and docile creatures. They are slow moving and hardly ever bite. This demeanor has served them well in becoming a popular up and coming pet in the industry. They can be easily handled often without becoming irritable and are relatively easy to care for.

Terrarium size

As with any animal, the Mexican Red Knee Tarantula needs an ample space to live, move around, and play in. The ideal size for a Mexican Red Knee’s terrarium is 5 to 10 gallons and should have a locking screen top.

Since the Mexican Red Knee is a burrowing animal, it is important to put enough substrate on the bottom rather than height that could be used for climbing. Ideally, you should put about three inches of substrate on the bottom of your spider’s terrarium to give it ample space to burrow.

Food & Water (What to Eat, How Much to Feed, How Often to Feed?)

It is important to keep a dish for water always full and available for your Mexican Red Knee.

As for food, the Mexican Red Knee Tarantula typically eats insects, such as crickets and other similarly sized bugs. They have also been known to eat small lizards, reptiles, and frogs as well as other small vertebrates such as birds and baby mice.

The Mexican Red Knee Tarantula usually eats once every week, though some of them have been known to eat up to three times a week. It is important to learn your spider’s preferences and adapt your care to it.

Returning to water, if your spider seems to be less than enthusiastic about drinking water from the water bowl you provided, do not worry. Mexican Red Knees can get all the hydration they need from the food they eat. However, you should maintain the habit of providing and changing the water bowl regularly so it does not grow mold and your pet always has that option if it so chooses.


Your Mexican Red Knee Tarantula’s terrarium should always be kept between 75 and 80 degrees Fahrenheit. This is the ideal temperature for your pet to live in since it best simulates the climate from its native area in Western Mexico.

This heat can be achieved and maintained by placing a heating pad under a portion or to the back wall of your pet’s terrarium.

Heating (Do Mexican Red Knee Tarantulas Need Heat?)

As long as you keep your spider’s terrarium at a constant 75 to 80 degrees Fahrenheit at all times, your pet should not need any other source of heat.


The Mexican Red Knee Tarantula does not need a high level of humidity. The humidity in its terrarium should be kept at around 65 to 75%. The humidity should never be allowed to dip below 55%, though. Keeping a water bowl in the tarantula’s terrarium will be a big help in maintaining the necessary humidity levels.


The Mexican Red Knee Tarantula does not require any lighting. However, if, instead of using a heat pad, you wish to provide your pet heat using a heat lamp, you can utilize this. However, a heat pad is more than ample to provide the heat your spider needs.


Males are typically ready for mating at ages four to five, females at ages six or seven. After the male and female mate, the eggs will hatch about one to three months later and the spiderlings will emerge from the egg sac three weeks after that.

If you would like your male Mexican Red Knee to mate with someone else’s female, it is important to keep in mind that females are usually more aggressive than the males, especially during the mating process. Females have been known to try to kill and eat the male after mating. Be cautious with your pet and try to remove it from the female’s presence soon after mating it done.

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