Mexican Red Knee Tarantula (Brachypelma hamorii formerly B. smithi) Care Sheet

Scientific Name: Brachypelma hamorii (formerly B. smithi)

Common Name: Mexican Red Knee Tarantula

Type: Terrestrial

Endemic Location: Mexico

Diagonal Leg Span (DLS): 5.5”  (14cm)

Growth Rate: Medium - Slow

Life Expectancy: Females 25-30 years / Males 10 years

Recommended Experience Level: Beginner

  The brachypelma hamorii, formerly classified as the Brachypelma smithi, known commonly as the Mexican Red Knee Tarantula, is one of, if not the most, popular tarantula in the hobby. When most people think of a tarantula, this is the species that they picture in their mind. Made famous by being used in movies like Indian Jones and the William Shatner movie Kingdom of the Spiders, this species was also showcased at the end of the episode “Realm of Fear” on Star Trek the Next Generation as a pet of Miles O'brien he named Christinia and said it was a Lycosa tarantula found on Titus IV. This species is endemic to Mexico found mainly along the western coast south of Guadalajara in the drier savannas and scrublands. This is a New World terrestrial, opportunistic burrower and was listed in CITES in 1985 due to dwindling numbers in the wild as a result of specimens being captured for the pet trade and other uses. These tarantulas were very popular in China at the time and the excessive importing had a huge effect on the number that could be found in the wild. This wasn't the only issue facing this species as many of the local people where the Red Knee is found saw them as pests or even bad luck and would exterminate them on site, further leading to their dwindling numbers. Listing them on CITES protected the species from eradication and halted exportation without the proper documents permitting them to be removed and shipped out of the country. By that time though, this species was already well established in the hobby and bred regularly making it one of the most common tarantulas in the hobby. This is due to its attractive and bright colorations with gorgeous black and orange patterns, its docile nature, and easy care and husbandry. 

   Like most species from Mexico, this tarantula is very easy to care for. I keep my spiderlings in small acrylic boxes filled halfway with substrate. I usually use coco fiber, peat moss, or creature soil, and keep the substrate slightly damp while they are small and vulnerable. I provide a hide and plenty of depth so they can burrow. I keep mine in my spiderling nursery that has a constant temperature around 76f and provide a small water dish if there is room or drip a little water on the web or side of the enclosure a few times a week. When they outgrow that enclosure I move them into my juvenile terrestrial enclosures which are usually an AMAC box or something a little fancier like the Tarantula Cribs juvenile enclosures. I keep the enclosure filled at least halfway or more with substrate and make sure there is no more than 1.5x the tarantulas leg span from the floor of the enclosure to the lid to reduce any damage from a fall. I provide a hide, water dish, and maybe a few plastic plants for decoration. I keep the water dish full but let the substrate remain dry, occasionally overflowing the water dish once or twice a month but always allowing it to completely dry before over flowing again.  And when they reach their adult size I move them into 2.5 - 5 gallon size enclosures. There really is no need to keep them in any enclosure larger than that, but some people do prefer to keep their adults in a larger enclosure like a 10 gal aquarium or acrylic enclosure equivalent in size. Again it is important to fill the enclosure at least ½ if not higher with substrate so that there is no risk of the tarantula crawling up the side and falling from the top rupturing its abdomen. I mainly use coco fiber at this size as they prefer a more arid environment and eco earth is very inexpensive, but any of the typical tarantula substrates will work fine as long as you keep them dry. I provide a water dish and hide and overflow the water dish once a month and then let the substrate in that corner dry out before overflowing again. 

  As far as feeding, I give my slings size appropriate prey once or twice a week. Usually I use pinhead crickets or roaches no larger than ⅔ the size of the sling. If I don't have anything that small, I prekill the prey before dropping it in or cutting up large crickets or mealworms and just feeding them pieces. They are scavengers at this size and will typically eat pre killed prey with no issues. I remove any uneaten prey or prey pieces within 24 hours and wait at least 48 hours after a molt before attempting to feed again. For juveniles I will feed 1 or 2 small to medium crickets a week and determine the frequency based on the size of the abdomen, I feed more prey more often when the abdomen is small, then as the tarantula gets plump, I feed less prey less often. Over feeding a tarantula does not cause it to grow faster. I usually wait about a week after my juveniles molt before feeding them again. For adults, depending on their size, I usually feed 6-8 large crickets every other week. Again, more prey more often when they are thin or recently molted, and less prey less often as they get plump. It is not uncommon for this species to go weeks or even months refusing food. They are naturally opportunistic feeders and usually only eat when prey crosses their path around their burrow. So your tarantula, especially as an adult, may not show interest in food for long periods of time. This is not a cause for concern and is normal behavior. When this happens, I just wait a couple weeks and try to feed them again. If they don't eat, I always remove the prey within 24 hours and wait a few more weeks before attempting again. You don’t want to leave crickets or any other prey in the enclosure for long periods of time when your tarantula is not eating as it may molt and live prey roaming around could stress them out and even cause injury or death to your tarantula as they are very vulnerable during and immediately after a molt. I wait about 2 weeks after my tarantula molts before attempting to feed, giving ample time for the exoskeleton and fangs to harden up. 

  There is a reason this one of the most popular species in the hobby and that is because it so beautiful, docile and easy to care for. They can be a little bit of a hair kicker and their urticating hairs could cause itching and even a little swelling, especially if you are sensitive. Their venom is not known to be medically significant and they are much more apt to run and hide than give a threat pose or try and bite. There has also been a little confusion about this species lately as for many years this tarantula in the hobby was classified as the Brachypelma smithi and sold as such. Recently, upon closer examination, there were some subtle differences and it was concluded that what we have in the hobby that was classified as the B. smithi is now reclassified as the B. hamorii and the species that was classified as the Brachypelma annitha, is in fact correctly classified as the B. smithi. I will leave a link in the description to the entire paper if you are interested in diving deep on the name change and getting a more detailed explanation.