I’m embarrassed to admit that when the Brazilian White Knee tarantula started to enter the hobby I was far from impressed. At the time I was focusing my attention on the more colourful species of tarantula such as the Greenbottle Blue, the Cobalt Blue and the Indian Ornamental.

Then along comes a tarantula that is just boring brown with white stripes on its legs – hardly what you’d call exciting when compared to brilliant blue and yellow specimens. But in retrospect I realized what a big mistake I made. Fortunately, this all became clear in the last few years when I finally picked up a few juveniles at a knock-down price.

Now, the Brazilian White Knee tarantula (Acanthoscurria geniculata) has become one of my favorite species of tarantula for a whole load of reasons. Where shall we start? Firstly, I have found that the Brazilian White Knee has one of the healthiest appetites of any tarantula I’ve kept.

Mine eat pretty much every single day unless they’re coming up to moult! What’s more they don’t mess around – the locust has barely touched the substrate before they pounce on it like a starved tiger. It really is something to see – and that makes feeding this species brilliant fun!

There’s more. This rate of feeding also makes them very fast growing tarantulas indeed, rather like Salmon Pinks, and even a small specimen will grow so fast you’ll be shocked. This means that they’re a great tarantula choice if you want a big, chunky specimen but are on a small budget. Just buy a tiddler and feed them liberally; in months they’ll grow bigger than you could imagine.

But what about those “boring” colors? Well, get up close to a Brazilian White Knee tarantula and you’ll find that they actually have quite a subtle beauty. This is also helped by how big they get – and how quickly.

If you’re looking for a big, impressive tarantula that grows rapidly and eats like its never seen food before then this is the tarantula for you! Let’s discuss exactly how to keep this species now in our detailed Brazilian White Knee tarantula care sheet…

Wild Habitat of the Brazilian White Knee

As the name suggests, Acanthoscurria geniculata is South American tarantula species. Originally described in 1841 by Koch, they are typically found in the Amazon rainforest areas of Brazil. Published field studies have noted specimens in Roraima, in the Carajás region and in Floresta Nacional de Caxiuanã.

This location data highlights that the Brazilian White Knee tarantula is most encountered in the north of Brazil, which is coincidentally also the least-populated area of the country. Sadly, this area is also rich in mineral deposits, and houses some of the largest iron ore mines in South America. Limited conservation studies have yet to reveal whether these activities are impacting numbers of this species.

This equatorial part of the world maintains a comfortable year-round temperature of around 26’C, with heavy rainfall during part of the year and generally quite high humidities. This habitat data suggests that both in size and lifestyle it may be wise to see the care of Acanthoscurria geniculata is being similar to spiders like the Salmon Pink Birdeater.

One interesting point worth making before we move on is that this is considered to be the first species of tarantula to have it’s DNA sampled. Scientists in Denmark announced in a paper published in Nature that they had completed a “draft assembly of the mygalomorph Brazilian white-knee tarantula, Acanthoscurria geniculata” in 2014.

Brazilian White Knee Housing

I rarely see Brazilian White Knee tarantulas for sale as adults – though it does happen. More likely you’re going to end up purchasing a juvenile and rearing it up to maturity. So while that baby Acanthoscurria geniculata might be fine in a small plastic tub for a few months it will likely soon outgrow this home. Soon enough they’ll be needing a “proper” tarantula tank that gives them suitable space to move around and live a natural lifestyle.

For mid-size Acanthoscurria geniculata I use a variety of plastic tubs. The best ones have a hinged lid so that I can peel open one end of the cage and throw in their food without having to take the whole lid off. They also have ventilation holes to allow air to circulate freely.

For larger specimens, however, a good-size glass or plastic cage will be required. Due to their impressive adult size (this species may reach a legspan of 8”) I would suggest a floor area of some 8” x 10” at the minimum, though I like to house mine in larger cages where I can add some more natural features to really set them off a treat.

In a cage of around 30cm in each direction you’ll be able to landscape the cage, including logs, artificial plants and more to really create an amazing display.

You may find that your local reptile store stocks specialist tarantula tanks made from glass or plastic with suitable ventilation. Alternatively my preferred choice for tarantulas are Exo Terra cages, which look great and offer a long list of practical benefits. They have a grill lid to allow for suitable ventilation, they’re easy to heat and the lockable front-opening doors make feeding and routine tank maintenance a breeze.

Heating & Temperature

Over the last few years of keeping Brazilian White Knees I have found that they seem to prefer cooler temperatures than many other tarantulas I keep. I have youngsters in plastic tubs that are housed in an “incubator” – essentially a wooden snake vivarium that has a heater placed at the back.

This provides roughly 27’C, but my Acanthoscurria geniculata always seem to be pressed up against the cooler end of their cage where the temperature is closed to 23’C. I have since therefore moved them into a different vivarium where the temperature is lower (thanks to a smaller heater) and they seem much happier.

Therefore I would recommend a temperature of around 22-24’C at the hot end of your Brazilian White Knee cage. As I have found, however, only one end should be heated, while the other remains unheated. This subsequently allows your tarantula to migrate to a cooler area if they so desire.

The easiest way to provide this heating is with a heat mat. These are available in a range of different sizes for a very modest cost, and represent a cheap and practical way of providing artificial heat for your tarantula.

It is also advisable to invest in a thermometer so you can monitor the temperature within your Acanthoscurria cage. My personal preference here is for a digital thermometer designed specifically for exotic pet keepers.

They have one or more temperature sensors attached to wires, which can be fed into the cage. The best ones that I have found have two probes, allowing me to monitor both the hot and the cool end of the cage without disturbing my spiders.

Water & Humidity

While Brazilian White Knees come from tropical Brazil, and therefore appreciate a reasonably high humidity, they don’t seem to do very well on damp substrate.

My choice is therefore to spray their cage once or twice a week, allowing it to dry out between sprayings. For this I either use a simple houseplant spray gun, or simply dribble a little water onto the substrate in the warmest part of their cage.

More importantly, larger tarantulas should be provided with a full, clean water dish so that they can drink whenever they so desire. For this I use small water bowls intended for reptile keepers or small mammals, though some people simply use an upturned bottle lid. This should be regularly cleaned and replenished to keep the water fresh.

Cage Furnishings

There seems to be some disagreement in the hobby about whether or not this species of tarantula likes to burrow. Some keepers find that their specimen readily tries to construct a burrow in which to hide, while others find that their spider barely breaks the surface.

Whatever the case, the first port of call when decking out your tarantula cage will of course be some suitable substrate. Options can include “rainforest substrate” as sold in some reptile stores, or my preferred choice of coconut fibre.

This substrate looks good, permits burrowing and is quite reasonably priced. Simply purchase a compacted “block”, soak it is water so that it expands, then deck out your cage.

You may want to try providing a decent depth of substrate initially – perhaps some 6-12 inches for adults – to see whether they try to construct a burrow. Alternatively, a thinner depth can be provided if you’re confident that your Brazilian White Knee doesn’t burrow.

In either case, a suitable hide should be provided, under which your spider can conceal themselves. As these spiders may burrow, it is crucial that any hide you use is very lightweight; you don’t want your pet getting crushed if it burrows beneath. Decent-sized pieces of cork bark are ideal for this purpose.

Depending on the size of the cage you selected earlier, you may also want to consider landscaping the cage with artificial plants to really make the cage an attractive feature.

Feeding Acanthoscurria geniculata

If I had to point out my favorite thing about Acanthoscurria geniculata it would be their feeding response. Seriously; these guys are monsters when it comes to eating. Unless they’re coming up to moult these fast-growing spiders never seem to turn down a meal. Indeed, I have specimens that will eat every single day between moults!

As this is a large spider you’ll want to feed good-sized prey items – big roaches and locusts are ideal. Some may even take the odd dead mouse if you also keep snakes.

Just be sure to keep your fingers well clear when feeding your Brazilian White Knee as they react so swiftly you don’t want to accidentally get nipped in the carnage!

Feeding this species can be such fun, especially if you have guests round. Try opening up the cage and dropping a feeder insect in for instant entertainment!

Handling the Brazilian White Knee

Hobbyists are divided when it comes to handling Acanthoscurria geniculata. Some people point out that these are reasonably docile spiders, and very rarely try to bite. On the other hand, the Brazilian White Knee has potent urticating hairs, which is readily kicks off.

Many people find these hairs cause irritation and therefore makes handling this species less tempting. Additionally, while bites are rare, this can be quite a large and skittish species. This means there is a risk of them getting dropped or making a run for freedom.

All in all, I think it is fair to say that if you’re looking for a tarantula to hold then this probably isn’t the species for you. Instead you might want to consider slower moving and more docile options such as the Brazilian Black, Rose Hair or Mexican Red Knee.