Brachypelma smithi (FOP-Cambridge, 1897), also known as “Mexican red-kneed tarantula” and “Mexican red knee”, is a stunning bird spider due to its coloration and behavior from Mexico. Exceptions still name her by one of her old names, “Eurypelma smithi” or “Euathlus smithi“. The spider is recommended for beginning hobbyists, as she is beautiful, easy to keep and very docile. For this reason the species has been smuggled a lot, mainly to China, almost endangering them to extinction in their natural habitat (source). In order to save the species, please don’t buy wild caught Brachypelma smithi, but get them from successful breeders. The current distribution of red-kneed tarantulas shows that the Balsas River basin may act as a geographic barrier. Morphological and molecular evidence were concordant and together provide robust hypotheses for delimiting. Therefore Brachypelma annitha was recently proposed and accepted as a new synonym of Brachypelma smithi (source). Don’t confuse the spider with Brachypelma auratum or Brachypelma hamorii.
We’re expecting many changes. Here’s why.
I. SPECIFIC INFORMATION
Scientific name: Brachypelma smithi.
Common names: Mexican red-kneed tarantula, Mexican red knee.
Previous names: Eurypelma smithi FOP-Cambridge, 1897, Euathlus smithi Baxter, 1993.
Type: Terrestrial bird spider.
Category: New world tarantula.
Urticating setae: Yes, type I and III (abdomen).
Venom: Probably mild. No valuable scientific research has been done yet.
Body length: ≤ 7-8 cm.
Span width: ≤ 15-18 cm.
Behavior: In general Brachypelma smithi is very docile, the perfect species for beginning hobbyists. Persistent provocation can result in use of urticating setae. In order to detect their prey easily, they’ll create an almost invisible and tangled web on the surface at the entrance of their burrow. The Brachypelma-genus possesses beautiful colors, not hiding them at all. They’re out most of the time, waiting for unexpecting prey to pass.
Growth rate: Slow.
Life expectancy: Females become up to 25-30 years old. Males are given a shorter lifetime of 4-5 years. Exceptions get 10 years old, which is very old for a male tarantula. Nevertheless most males die within 2 years after making their spermaweb.
Availability Colima-form is easy to get. Guerrero-form is rare. The rarer, the more expensive.
Accessibility (1/beginner, 10/expert): 1.
II. INFORMATION FOR KEEPERS
>>> First aid
Brachypelma smithi is native to the western faces of the Sierra Madre Occidental and Sierra Madre del Sur mountain ranges in Mexico, being subtropical warm and rather dry except for 4 months. Temperatures almost daily reach levels up to 25°C, with maxima around 30°C. Please be informed of the fact the spider will protect itself against the sun underneath tree trunks, branches, leaves, abandoned burrows and rocks. Do not overheat the terrarium.
Temperature: 25-29°C (day), 20-22°C (night).
Adult: LxBxH: 40x30x30. Min. 3-4x span width in surface.
Smaller than adult: Min. 3x span width in surface.
Adult: 3/4 span width. Brachypelma smithi likes to burrow from time to time.
Smaller than adult: 1,5-2x body length.
* Keep the substrate rather dry.
* Do not give more than 20 cm of free space between ceiling and substrate.
Wet season: June, July, August, September.
Dry season: January, February, March, April, May, November, December.
Warmest month: June. Temperatures in general are high.
Coldest month: January.
For more information about the local climate: Click here.
* You might like to consider an adjustment of these data with your local climate. Do not exceed minima or maxima and, if necessary, organize the year making your bird spider experience different seasons. This is very important form the moment you’d like to start breeding.
Subdividing the Brachypelma-genus
Red hairs on the legs
• West-Mexico, along the Pacific Coast, and Sierra-Madre.
• Natural and captive bred hybrids are known. Inform yourself in order to make sure you’re breeding the same species.
Red hairs on the abdomen
• Widespread over Central-America.
• Thoroughbred species can be hard to find in the hobby. Besides the true Brachypelma vagans, for example, you’ll often see them show up as “Brachypelma vagans hobby form”, being a hybrid of a female Brachypelma vagans and another male from the Brachypelma-genus (probably Brachypelma schroederi or Brachypelma albopilosum (hobby)). Please leave the breeding to the professionals.
III. INFORMATION FOR BREEDERS
Caution: Because of the fact species from the Brachypelma-genus can be very similar, it’s hard to distinguish one from another. However people breed species with good intentions, different species have been mated plenty of times being convinced of the fact they were the same. Thoroughbred species from the Brachypelma-genus are available in the hobby, but make sure your source is valuable.
With a little experience, breeding a Brachypelma smithi is not that difficult. The females are exacting, as you’ll need to simulate both winter (6-8 weeks (no food)) and spring (3-4 months (lots of food)). Let the terrarium dry out, but keep substrate slightly moist, because the female doesn’t like a humid environment close to her posterity.
• Only start breeding 4-6 weeks (or later) after the spider molted. If the female molts between pairing and cocoon, the eggs will remain unfertilized.
• Make sure the female is well-fed (not obese) before you introduce the male.
• Plan mating in autumn.
• Simulate a winter from 6-8 weeks (10-15°C), 2 months after mating. Don’t feed or bother the spiders during this period.
• Systematically increase temperatures (25-29°C) and moisten substrate (70-75%) once after winter. Make sure there are no puddles inside the terrarium. Keep temperatures perfect, as you triggered the female to start making her cocoon.
• From the moment the female is visible at the entrance of her burrow, you might expect 150-550 spiderlings to come out 8-10 weeks later. Deprive the cocoon, when desired, 7 weeks after you’ve seen her protecting the cocoon. Store the eggs at a humidity of 65-70% and a temperature of 26-29°C.
IV. DID YOU KNOW…
• Brachypelma smithi is the favorite species for beginning hobbyists?
• Western hobbyists often own a Brachypelma smithi from Colima? Brachypelma smithi from Guerrero is more colorful, fluffy and doesn’t possess black setae around the red on the pedipalps.
• Your success breeding bird spiders living in a rather dry environment always depend the way you simulate seasons?
• Brachypelma annitha was proposed and accepted as a new synonym of Brachypelma smithi in 2016 (source)?
• Brachypelma smithi on Animal Diversity Web.
• Photography: Leon Kirkbride (youtube)