Mexican redknee tarantula
The Mexican Red-kneed Tarantula (Brachypelma smithi), is a species of burrowing tarantula native to the western faces of the Sierra Madre Occidental and Sierra Madre del Sur mountain ranges in Mexico. The natural scrub-forest habitat is complex, where shading retains moderate humidity (around 55-65%). Many older books are in error in saying they are from desert/arid habitats. They are among the most popular tarantulas available in the pet trade, due to their impressive size, striking coloration, and general docility. They are a slower growing species; it is not uncommon to have females live 25 years or more. They carve deep burrows into soil banks, which keep the spiders protected from natural predators like White-nosed Coati.
The mature Mexican redknee tarantula has a dark-colored body with orange patches on the joints of its legs; the second element of the legs (the trochanter) is orange-red. Following moulting, the colors are more pronounced. The dark portion is very black while the orange-red portions will be far more on the reddish side.
An adult female has a body roughly 4 inches (10 cm) long, with a legspan of 6–7 inches (15–18 cm), and a weight of approximately 15 to 16 grams.
In the wild, they will consume almost any kind of arthropod, small lizard, or small rodent that they can overpower and immobilize with their venom. In captivity, baby spiders have to be fed with small flies, such as fruit flies (Drosphilia ). When they are around half a centimeter in size, one can switch to small crickets. Adults can be regularly fed mealworms and adult crickets. Optionally and very occasionally baby mice may be used as food. A large meal is often enough to sustain the tarantula for several weeks before it needs to eat again.
A tarantula molts (sheds its skin) when the skin is too small. After molting, it will emerge from its exoskeleton, leaving the old skin behind, often fully intact, and almost looking like a second spider. They are also capable of kicking what are called urticating hairs from the rear of their abdomen. These hairs are irritating to the skin, causing itching and sometimes blistering. If they are introduced to the eye, they can cause damage to vision.
The Mexican redknee is a rather docile species. That, coupled with amazing coloration and impressive size, makes them a very popular pet species.
An enclosure measuring approx. 30 cm × 30 cm × 30 cm (11.8 in × 11.8 in × 11.8 in) is adequate to house them. A heat mat or cable is recommended for underground heating, but only a fraction (max 1/4) of the tank should be exposed to heat. They can be kept on a substrate of fairly dry peat, mixed with around 30% sand, and coir for fibre (and even mixed with vermiculite). At least one corner of the tank should be higher humidity, up to about 65%. To achieve this a large open waterbowl can be used.
B. smithi is a terrestrial species that rarely burrows so a deep substrate may not be a requirement. You must instead provide a hide area, such as a semi-circular piece of cork bark, woodtrunk or terra cotta flower pot half buried in the substrate. The burrow should maintain higher humidity than the exterior regions of the false habitat.
Live plants are typically discouraged from tarantula enclosures, as they can often attract pest insects.
All tarantulas can be fed on commercially available insects, like crickets, locust, cockroaches and other feeder insects. Adults should be fed weekly or less and depending upon their size and age, one item is usually enough. The abdomen should look well rounded, but not obese. When a tarantulas abdomen is plump, it is more prone to impact damage in the event of a fall, which can lead to the death of a tarantula due to loss of fluids.
Younger tarantulas should be fed smaller prey insects (less than the size of the spider) about once a week. They will eat small crickets, but also can be fed other insects, such as mealworms, tiny locusts, or waxworms. However like many other tarantulas they may not prefer to eat mealworms or waxworms. Any prey insects that have not been eaten in 24 hours should be removed from the enclosure, as these may actually attack the spider during a vulnerable molting period, when its exoskeleton is softest. For larger spiders, water can be provided in a shallow dish (with only a thin layer of water) or by misting one corner the enclosure with a spray bottle - which is the best solution for both large and smaller spiders (although tarantulas usually meet most hydration needs through their prey). If the abdomen looks wrinkled in any way, then dehydration is likely, and water must be made available.
For years these spiders were mislabeled as being a desert species, resulting in the deaths of many spiders from inadequate humidity. It is best to maintain a range of temperature and humidity in the tank, with an area where the spider can rest in moderate 55% humidity (and ideally the burrow and the water-dish here), and a drier area of substrate over a heat source. The average enclosure humidity should never fall below 40 percent.