Mexican red-knee tarantulas are actually two different spider species that are native to the Pacific coast of Mexico. Brachypelma hamorii and Brachypelma smithi both have vibrant reddish-orange "knees"—i.e., the middle portion of their legs—that contrast with their black bodies.

As pets, these spiders are favored for their beauty, generally docile temperament, and long life span. They often make good pets for first-time spider owners. Plus, their housing doesn't take up much space and their diet is relatively straightforward.

Learn more about the Mexican red-knee tarantula and how to care for them.

Mexican Red-Knee Tarantula Behavior and Temperament

The Mexican red-knee tarantula is one of the most docile and calm pet tarantulas, making them ideal for beginner arachnid keepers. This spider rarely bites.

However, it's important to note that their bite is venomous. And like most tarantulas, they will eject urticating hairs from their abdomen and legs if they think they're in danger. These hairs can embed in the skin and cause irritation; they also can be seriously damaging if they get in your eyes. This is why it's important to wash your hands well after handling your spider or anything in their environment.

Still, many Mexican red-knee tarantulas are comfortable with gentle handling, though they don’t need the socialization. It’s important to sit on the floor when handling one, as an accidental drop from even a few feet can be seriously damaging. Keep handling sessions brief to avoid unnecessary stress.

Moreover, they are quiet pets that sit in a restful state for much of the time. They should be housed individually and kept away from other household pets to prevent injury and stress. Plan to spend a few hours per week on feedings and keeping the enclosure clean.

Size Information

Mexican red-knee tarantulas have a leg span of around 5 inches, and they weigh roughly 0.5 ounce. The females are generally slightly larger than the males.

Housing

Keep your tarantula in a glass or plastic aquarium with a secure top that has ventilation. As a general rule, the tank should be roughly two to three times wider than the spider’s leg span and roughly as tall as the leg span. Ideally, it should have a side opening. Tarantulas like to hang upside down at the top of the tank, so this will prevent the spider from falling each time you need to service the tank.

Heat

Maintaining a consistent temperature and humidity level is an important element of Mexican red-knee tarantula care. The recommended terrarium temperature is around 75 to 80 F, and this can be achieved by using a heat mat under one portion of the tank.

While supplemental heating is recommended for most North American terrarium environments, it's also important to give your spider an unheated area to cool off should the tank get too hot.

Humidity

Keep the humidity level at 60-70%, which can usually be achieved through evaporation from a water bowl. However, in some dryer homes, misting the tank might be necessary.

If you see your spider hovering over their water bowl but not drinking, chances are your environment is too dry. Conversely, if they're continuously hiding out in a far corner of the terrarium, your enclosure is probably too humid. You can measure the tank humidity with a hygrometer.

Specific Substrate Needs

The substrate, or bedding in the tank, should be a mix of peat moss, soil, and vermiculite. Make it at least 4 inches thick and loosely packed to allow for burrowing and to dampen any falls.

Within the tank, wood, cork bark, or half of a small clay flower pot can provide good shelter for the tarantula. Adding a few fake plants also helps mimic their natural environment.

What Do Mexican Red-Knee Tarantulas Eat & Drink?

Mexican red-knee tarantulas like to eat:

• Live crickets (these will be a staple in your Mexican red-knee tarantula's diet)
• Roaches
• Locusts
• Other insects, such as mealworms, flightless fruit flies, and black soldier fly larvae

A pinky mouse or a small lizard may be fed occasionally as a protein boost, but make sure to clean the remains from the tank immediately.

Also, remove any uneaten live insects, as their constant movement can stress your pet spider once they're full.

Mexican red-knee tarantulas usually eat once or twice a week. Consult your vet on how much and how often to feed, as this can vary based on factors such as age and size. To feed, simply drop the prey in the tank. This is best done in the evening when the spider is more active. 

The tarantula also needs access to fresh water at all times both for hydration and humidity. Provide a shallow water dish that your spider can easily get in and out of. Refresh the water every day.

Common Health Problems

Most pet tarantulas are hardy creatures that rarely fall ill when kept in the proper environment. Accidental falls are one of the biggest dangers to their health, which is why a secure enclosure and careful handling are so important.

As with all tarantulas, the red-knee tarantula will go through the molting process to shed their old exoskeleton and grow a new one. During this time, spiders often refuse to eat and might lie immobile on their back. It can look startling and appear as though the spider is sick or dying, but it's all normal. Avoid handling your spider during this time. And don't feed any live prey for about a week after the molt is complete, as even a cricket can damage the fragile new exoskeleton. 

Exercise

Just like with any animal, physical activity is important to keep a Mexican red-knee tarantula in good body condition. However, this spider doesn’t need a great deal of exercise. As long as you provide a large enough tank, they should be able to get all the activity they need.

Grooming

Tarantulas essentially “groom” themselves via molting. They typically don’t require any help from you besides making sure their environment is at the right temperature and humidity and keeping live prey away from them until their new exoskeleton has hardened.

Upkeep Costs

From month to month, the primary cost for a Mexican red-knee tarantula will be their food. Plan to spend between $5 and $10, on average. You can diminish this cost by raising crickets yourself instead of purchasing them from a pet shop.

Occasional substrate changes can cost between $10 and $20, on average.

Also, make sure to budget for veterinary checkups and emergency care. 

Pros & Cons of Keeping a Mexican Red-Knee Tarantula as a Pet

Mexican red-knee tarantulas are interesting, quiet, and low-maintenance pets. They also don’t take up a lot of space. However, they’re not the best choice for those who want a cuddly and social pet.

Similar Spiders to the Mexican Red-Knee Tarantula

If you’re interested in pet tarantulas, check out:

• Curly Hair Tarantula
• Chilean Rose Tarantula
• Costa Rican Zebra Tarantula

Otherwise, check out other tarantulas that can be your pet.

Purchasing or Adopting Your Mexican Red-Knee Tarantula

Before you purchase a Mexican red-knee tarantula for a pet, be aware of their life span. A female pet tarantula can live for decades, making them a long-term commitment. 

Because this tarantula species is popular as a pet, you often can find them at pet shops. But going to a reputable breeder or rescue organization is often the better choice to ensure you are getting a healthy animal.

Expect to pay between $50 and $100, on average, though this can vary widely based on factors such as the animal's age and sex.

Reproduction/Breeding

Check with local exotic veterinarians for recommendations on a good breeder or rescue group. The primary benefit of going to a breeder is you’ll likely have a wider selection of younger animals to choose from. The seller should be able to provide information on the animal’s history, sex, age, and health.

When choosing a spider, avoid those that appear hunched or shriveled in any way. Ask the seller whether you can see the spider eat if possible. And to avoid accidentally becoming a breeder yourself, keep multiple tarantulas housed individually.