Mexican Red Knee Tarantula (Brachypelma hamorii) Care Sheet

Brachypelma hamorii, better known as the Mexican Red Knee tarantula, is one of the best-known of all theraphosid spiders.

Tremendously popular in the early days of the tarantula keeping hobby, it remains a staple in the trade today. Unlike the early years, where specimens were captured in the wild and shipped worldwide, a CITES listing means all current pet specimens are now captive bred.

The Mexican Red Knee is in many ways the “perfect” tarantula. It grows to a healthy 5-6″ legspan, has a chunky look that is almost “cute” (to some people at least) and is brightly coloured.

This tarantula is primarily black in colour, but benefits from bright orange and yellow hairs on the “knees”, as well as on the abdomen.

Placid in nature, and very long-lived, this is an ideal tarantula for keepers of all abilities and experience levels. The only downside, if there is one, is that Brachypelma hamorii tends to be quite a slow-growing species, meaning that you’ll need to be quite patient if you opt to buy spiderlings and rear them to adulthood.

brachypelma smithi photo

Mexican Red Knee Wild Habitat

The Mexican Red Knee was originally described in 1897 by well-known biologist F.O. Pickard-Cambridge. It is found across a wide range, encompassing the south of North America and areas of Central America.

It’s primary footholds are considered to be in Mexico and Panama, where it may share its range with other members of the genus, most notably Brachypelma emilia, the Mexican Red Leg tarantula.

Tarantula expert Rick West has studied the species in the wild, claiming their burrows are normally to be found “in dense thickets or vegetation” of both dry thorn forests and tropical deciduous forests. Other studies have found burrows frequently near the bases of rocks.

Occupying such a wide variety of environmental conditions, this is an adaptive and sturdy tarantula, which makes it easy to keep in captivity.

As pets, it is generally considered best to adopt a “mid-range” environment, offering an average daily temperature and humidities below those of more decidedly tropical species.

Important Taxonomic Note: The tarantula we now know as Brachypelam hamorii was for decades known as Brachypelma smithi. The name Brachypelma smithi has now been given to another tarantula from the same genus after a taxonomic update. Consequently, many older forum posts talking about “Brachypelma smithi” are instead referring to what is now “Brachypelma hamorii”.

brachypelma smithi photo


One factor which makes Brachypelma hamorii such a popular pet is how they seem more willing to sit out in the open than many other tarantula species.

They can therefore be excellent pets for the keeper who wants an impressive display. In truth, many tarantulas hide away for most of the day, rarely to be seen.

Some specimens may not be seen for weeks on end. Not so for the Mexican Red Knee, however, which can often be seen resting in plain sight in their vivarium.

There are a number of considerations when it comes to choosing a cage for your Mexican Red Knee. Tarantulas as a whole can be astonishing escape artists, so the first consideration should be a close-fitting lid and doors that cannot be opened.

In terms of dimensions, I have found that Brachypelma hamorii tends not to be the most active tarantula, so only a modest-sized cage is necessary. It is also important to point out that these are ground-dwelling tarantulas who naturally build burrows in the wild.

This is in contrast to arboreal species like Caribena versicolor which build nests off the ground. Cage height for this species is therefore of less concern than for some others.

A cage measuring some 12″ long by 10″ deep should be considered a minimum for adult specimens, though feel free to house them in larger cages if you desire. A cage height of around 12″ is adequate. In short, a cage roughly 30cm in all directions is a good rule of thumb for this species (and indeed many other Brachypelma tarantulas).

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So long as your cage meets all of the above requirements – dimensions, security, ventilation, heating – then it may be used. If you are a new tarantula keeper, considering buying your very first Mexican Red Knee then I recommend you consider looking at Exo Terra or ReptiZoo cages.

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These are built from glass and offer excellent visibility of your spider. Their hinged doors open up at the front, making it easy to feed and clean your spider, and the lid if made of sturdy mesh to allow air movement.

Tank Decor

brachypelma smithi photo

Brachypelma hamorii is a reasonably undemanding species to keep as a pet, and very few accessories will be required to keep them happy.

It all starts with the substrate, which not only helps to moderate the humidity, but can also be used for burrowing. This is where some disagreement exists among hobbyists. Some claim that it is best to add a thick depth of substrate, so that your tarantula can try to build a burrow. Some 6-8″ of substrate is recommended.

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Others point out that wild tarantula burrows can be almost a metre long, so it’s unlikely that your tarantula can build a “wild type” burrow in captivity. Furthermore, it seems even when offered the opportunity to build one, many Brachypelma hamorii simply refuse to play ball.

For this reason many cages are supplemented with one or more hides for privacy. A range of different hides are available for tarantulas, though two of the most popular options are either curved pieces of cork bark, or a flower pot laid on it’s side and partially buried.

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The hide should be large enough for your Mexican Red Knee to completely conceal itself within for privacy. If you have space to provide more than one hide then all the better; this gives your pet the opportunity to choose the “home” that suits them best.

Tarantulas from around an inch or so in body length should be provided with a very shallow water bowl, which should be cleaned and refilled regularly. While Brachypelma hamorii is used to surviving in dry environments, so may not be observed to drink often, it is considered best practise these days.

As a nocturnal species no artificial lighting is required for tarantulas, though if you have the inclination a very low wattage bulb (or one that gives red light) might be used to observe your tarantula after dark.

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Water & Humidity

brachypelma smithi photo

As described earlier, an open water dish should be available at all times, but it is important that this is shallow. Tarantulas are not known for their swimming abilities, so the shallow dish reduces the risk of drowning.

It can be a good idea to gently mist your Mexican Red Knee cage once or twice a week, allowing it to thoroughly dry out in between. Some tarantulas also seem to prefer drinking these fine droplets off the wall of the cage, rather than making use of their water bowl.

A houseplant mister works well for this purpose, though be sure it hasn’t contained any unpleasant chemicals before. It is generally best to buy a brand new mister and label it as “tarantulas only” to be certain. Avoid spraying the spider itself, which can cause distress.

Note that as Brachypelma hamorii survives quite admirably in drier environments in the wild, it is critical to avoid a cage that is soaking wet. The substrate should be allowed to dry out slightly between mistings, which if you’ve got the temperature and ventilation right should occur quite rapidly.

Feeding Mexican Red Knee Tarantulas

Brachypelam hamorii is quite a slow growing and long-lived species. Females may live for 20 years or more, but both sexes take quite some time to reach maturity. Unlike many more tropical species, the Mexican Red Knee has a far more sedate appetite. Twice-weekly feedings for youngsters and once or twice a week for adults tends to work well.

Note that the Mexican Red Kneed tarantula may go off it’s food for long periods of time, as they might during cooler weather in the wild. Some of my specimens stop eating for a month or more, especially before a moult. This is generally not anything to be worried about, assuming your spider appears otherwise to be in good spirits.

As mid-sized spiders Mexican Red Knees can eat any of the popular feeder insects. I primarily feed mine on locusts, though crickets and roaches are also options. Some may even take the odd pinky mouse if they’re feeling particularly hungry.

It is difficult to overfeed a tarantula, so feel free to feed as often as they will eat. It can be a smart idea to keep a feeding chart, so that you get used to how much and how often your spider eats. Such records also make it easier to ascertain when the next moult is likely to be happening.

I generally feed my tarantulas in the evening, as they are naturally starting to wake up. Any uneaten food is then removed the following morning to prevent it annoying the spider.

Handling Mexican Red Knee Tarantulas

One of the reasons that the Mexican Red Knee is so popular – and has been used in so many TV shows and movies – is simply how docile it is. Indeed, of all the tarantulas common in the trade, this is arguably one of the very best for handling.

They are slow moving, very rarely try to bite and attain a healthy size for the average adult to hold.

The one thing you must be careful of when handling this species are the so-called “urticating hairs”. These hairs can be kicked off if your tarantula feels stressed, and can cause irritation. One study records the hairs of Brachypelma hamorii leading to “itchy, gritty eyes”. The best bet, therefore, is to keep your spider well away from your face if you choose to handle it.

In brief, while experts recommend handling theraphosids as little as possible – for the safety of the spider – if you do want a spider that you can hold on occasion then you can’t do much better than the Mexican Red Kneed tarantula.

Images c/o brian.gratwicke, davidricardoabrenica & James St. John

Richard Adams

7 thoughts on “Mexican Red Knee Tarantula (Brachypelma hamorii) Care Sheet”

  1. Hello Richard, thank you for this informative care guide. I barely got a male Red knee and so far I’m liking it. I have a question though, do I apply daylight and nightlight to my tarantula, if I want to keep the temperature and humidity between the range? Like it will not make him stressed or over heat?

    • Hi Gerardo – I generally don’t recommend using light-emitting heaters for tarantulas. As you say – I feel this could stress the spider. Instead I prefer those heaters which provide infra red, and control them using a thermostat to prevent overheating.

  2. Considering getting one for my daughter, does the substrate need changed (bathroom waste?) ? I’ve seen other sites recommend a heating pad under the tank. Is this an appropriate temperature adjuster, and would I only primarily need in the cooler months in a Pennsylvania climate?

    • Hi Chad – Tarantulas are pretty clean animals in general. Of course the substrate will need changing occasionally, but probably a lot less than you might think. It’s a good plan to “spot clean” the cage on a regular (weekly?) basis – just remove any remnants of food, molted skins etc. This will keep most issues at bay. Under these circumstances you’ll rarely need to change all the substrate in one go. In terms of heating, most keepers now recommend either placing the spider into a warm room (70’f+) and it should be fine without artificial heating. If you do end up having to use a heater because your home gets too cold then heat mats are better placed on the side of the cage. The reason is that tarantulas often burrow down to avoid excessive heat. With heat coming from underneath they can actually get hotter not cooler when burrowing.


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