Scientifc Name: Brachypelma smithi (F.O.P-Cambridge 1897)
The Mexican Red Knee Tarantula is a long-lived and very showy tarantula that poses no particular problems if a few golden rules are followed. The beauty, ease of keeping and showiness make this an ideal starter tarantula.
This species has been confused with similar species; the common name has not helped with that confusion.
B. smithi is a reasonably large species with a basic black/midnight blue body. The carapace is dark and edged with a wide band of red. Each leg has red markings on the middle 3 (patella, tibia, and basitaurus) of the 5 leg sections: hence, the common name ‘Red Knee’.
Brachypelma smithi is a relatively peacful species. It is, however, quite skittish and has a tendency to flick urticating hairs when disturbed. The author does not recommend handling of any tarantula except for special cases; B. smithi individuals can, however, become accustomed to being handled. Technically, B. smithi is venomous.
5 – 6 inches
As a caresheet, there will be no presumption that the reader wishes to attempt to breed this species or any other species of tarantula. Readers wishing to breed tarantulas should be aware that breeding requires an input that goes further than a basic caresheet. However, a keeper should be aware that the lifespans of males and females are notably different: a female can expect to live in excess of 15 years; a male can expect to live 4 to 7 years.
A mature male will show tibial hooks on the front legs. Lack of tibial hooks does NOT mean the specimen is a female.
Examination of the molt (exuviae/exuvium) is the best method to sex a tarantula (never disturb the tarantula in removing the molt from the housing): males have a dense region of setae along the epigastric furrow (situated between the proximal booklungs) signifying the presence of epiandrous fusillade only found in males; females lack epiandrous fusillade; females have spermathecae (sperm receptor) found inside the abdomen between the proximal booklungs.
Sexing a tarantula requires good observation skills and some experience. Ad hoc and ‘gut-feeling’ sex determination based upon colouration, size or leg length should not be taken as a reliable guide.
The choice of substrate is not simply about selecting a suitable bedding; the choice and depth of substrate are important to maintaining a balance in humidity and in helping the spider shed its skin.
The substrate should be non-toxic and not able to cause physical damage to the spider. It must be able to hold some moisture, not degrade too rapidly and be as biologically neutral as possible so as not promote microbial growth. Care should be taken with ‘bark’ in that it is of ‘orchid-potting’ grade and does not contain cedar. Sphagnum peat, coire peat, sphagnum moss, and vermiculite are suitable substrates. A mix of peat, moss, and vermiculite allows the keepers to blend a mix that retains adequate moisture without becoming overly wet. The use of sand has been linked to blocking of the booklungs resulting in death.
Mexican Red Knee Tarantulas will dig burrows, but are equally happy with a shallow (2 to 3 inch) substrate with décor (such as cork bark laid horizontally on substrate or deeply planted rocks).
If a deeper substrate is selected, then care needs to be taken to not have any décor that may fall into a burrow.
Lighting and UVB:
Low level lighting. No direct bright lighting. No UV light.
Temperatures & Humidity:
Temperature should be 21 to 26 Celsius.
Although this species may tolerate lower temperatures, it is not advised to allow the temperature to stay below 16 Celsius for long.
Overheating can rapidly kill the spider.
Humidity should be between 40% and 60% relative humidity (raising to 80% in warm weather and if good ventilation ifs offered); as the temperature decreases then the humidity should decrease.
Wet or overly humid conditions and low temperatures will favour the growth of fungi.
Red Knees are not overly demanding with respect to housing so long as a few basic rules are followed.
The housing must be secure.
The housing horizontal dimensions should be a minimum of double the leg span and the height be high enough to allow the tarantula to turn itself over onto its back (this being roughly the length of the leg span).
The housing should not be too high for Red Knee Tarantulas; they like to climb but are not very good climbers: a fall from a height can be fatal for a Red Knee Tarantula. An excessively large housing should be avoided.
The construction of the housing should avoid toxic paints, toxic metals, toxic plastics, toxic glues, and toxic woods (such as cedar wood). The housing should have ample ventilation. Avoid using unsealed mesh or other ventilation covering that might form a trap hazard for the legs.
An all glass 18 long x10x10 inch fish tank with a suitably ventilated and secure lid is an ideal starting point for decorated adult housing.
Place the housing away from strong direct lights (especially sunlight) and away from vibrations.
None. Do not house more than one specimen per enclosure. Even bringing male and female together for breeding is risky.
Appropriately sized gut-loaded live food. As a general rule of thumb, the food should be no larger than the rump.
Suitable foods include crickets, locusts, meal worms, morio worms (for larger specimens) and cockroaches.
In some cases, the tarantula may accept freshly dead insects. There is no real justification in feeding defrosted mice or other vertebrate species to tarantulas. Different specimens may be choosey in their diet and some experimentation and patience may be required.
Feed between one and three times weekly. Observation of a particular specimens feeding behaviour is important: some specimens may only tolerate one live feeder at a time.
Do not overwhelm a tarantula with live feeder insects; newly acquired specimens may show stress if offered food; never allow feeder insects in a tarantula housing during a molt and within several days after a molt.
The spider will not require water at all times, but it should be made available to the tarantula at all times (or on a regular basis).
Young spiderlings should be presented water by way of droplets on the substrate.
Larger specimens should be offered water in a wide (wide enough for the spider to press its body into the water) shallow container. The water should be changed daily and should not contain any form of sponge or cotton wool or other such additions. The author sees no purpose to so-called gel-waters or sponges other than to provide a breeding ground for microbes and a place for live feeders to defacate.
Supplements, Nutrition and Usage:
Do not add supplements to food. Do not add supplements to water. Food should be gut-loaded prior to feeding.
The Mexican Red Knee Tarantula demands very little additional maintenance other than first supplying a suitable housing, conditions, food and water.
Dead feeder carcases and molts should be removed as noticed.
Watch out for fungal growth or a mite infestation or bad odours: if any are noticed then discard all substrate and thoroughly clean the housing. Clean the housing with warm water. Do not use detergents or bleaches.
Routine cleaning is required, but there needs for a balance. Too frequently, and the spider will become stressed and will also upset a balanced substrate and meaning a ‘new-house’ syndrome to develop too often.
Some keepers recommend cleaning 1 to 4 times annually unless problem develop within the housing.
Care sheet Courtesy of The Herpetological Society of Ireland 2009