Are Tarantulas Aggressive to Humans?

For many people, tarantulas are some of the scariest animals on the planet.

As a tarantula keeper with over two decades of experience probably the most common questions I get are about being bitten. With that in mind, in this article I’ll try to answer the question “are tarantulas aggressive to humans?

In general the answer is “no” tarantulas are not aggressive to humans. 

That said, this really only skims the surface of this fascinating subject. So let’s dig a little more into the answer for a more informed conclusion…

Aggressive Vs Defensive

Are tarantulas aggressive?

It’s important that we discuss the differences between aggressive and defensive behaviour in tarantulas. 

“Aggression” has been defined as “the action of attacking without provocation”. If that is true then tarantulas most certainly aren’t aggressive. While they may try to bite, they typically only do so in response to some kind of action that you’ve taken.

Perhaps you disturbed them.

Maybe you scared them out of their burrow, or grabbed at them.

The tarantula, feeling threatened, may be act defensively.

In this case, the spider is only trying to protect itself from what it deems as a danger. 

So I think the first crucial point is that while tarantulas can and do bite, this should be considered a defensive action rather than one of aggression.

Tarantulas don’t go around looking for people to bite, and the best way to avoid a bite is simply to leave tarantulas well alone to get on with their life.

Some Tarantulas are More Aggressive Than Others

There are hundreds of species of tarantula available to exotic pet keepers, and even more in the wild. It is interesting to note that each species can vary in the level of aggression shown. 

Some are very docile and can be held with little risk of getting bitten. Others, in contrast, can be far more highly-strung and are more likely to bite in defence. 

As a result, if you are looking to buy a pet tarantula but you’re concerned about aggression then it makes sense to choose one of the more chilled-out species.

Examples of Docile Tarantulas

Some examples of docile tarantulas that can be kept as pets include:

These are, however, a drop in the ocean and there are many more species that suit this description. 

Examples of Defensive Tarantulas

At the other end of the scale are those tarantulas that are considered more aggressive, and therefore are far less suitable tarantulas for beginners. Some popular examples include:

  • The Orange Bitey Thing (OBT) – Pterinochilus murinus
  • Horned Baboons – Ceratogyrus species
  • Chilobrachys species

These are really only suitable for more experienced keepers, who are used to dealing with fast-moving spiders with a penchant for aggression. 

Threat Postures as a Warning

Tarantulas bite for two reasons.

The first of these is hunger, where they simply pounce unannounced on an unsuspecting prey item.

The second of these, however, is a defensive bite.

The interesting thing is that many tarantulas give a warning before a defensive bite: they adopt a threat posture.

The threat posture is hard to ignore. The tarantula will rear up on its two hind pairs of legs, raising the front two high into the air. This reveals the fangs. The hair around the mouth is often another color too so this adds to the effect. 

Some species of tarantula – like the Indian Ornamental (Poecilotheria regalis) – have a different color under the legs too. A posturing Indian Ornamental will suddenly reveal a bright lemon-yellow underside to its front legs. 

Lastly, some tarantulas can “stridulate” – a process that involves rubbing together specialised hairs that then creates a “hissing” noise.

A tarantula displaying like this is telling you to back off. The next step is likely to be a bite.

So – consider these threat postures a fair warning of what is to come. When you see one you should step away and let things calm down.

What Happens if You Get Bitten By a Tarantula?

I’ve been keeping tarantulas for over 20 years and so far I’ve avoided a bite all that time. This, in itself, should suggest that if you treat your spiders with respect then you’re unlikely to get “tagged”. 

This aside, what happens if you are unlucky enough to get bitten?

Firstly, remember that a tarantula bite is a defensive behaviour, not one of aggression. Your tarantula just wants you to stop bothering you. The spider will likely therefore dash off in search of cover, leaving you to nurse your ego.

Make sure the cage is closed properly so you’re sure the spider is safe. 

Then go and sterilize your wound. 

Are Tarantulas Harmful to Humans?

In general a tarantula bite is said to be no worse than a bee sting. There’s a little local swelling and soreness but this soon goes away. 

In some Asian spiders the effect can be a little more serious and can last longer. This may involve swelling to the affected limb, joint pain and a burning sensation. Again, this generally seems to subside within a couple of days.

Unless you’re unlucky enough to suffer an anaphylactic shock then you should be right as rain soon enough.

I would suggest that if any more serious symptoms arise that you seek rapid medical assistance just to put your mind at rest.

Broadly speaking, however, tarantulas aren’t harmful to humans and you’ll soon be laughing off the bite before being more careful next time! 

Richard Adams

3 thoughts on “Are Tarantulas Aggressive to Humans?”

  1. Hi, Richard. I really find your blogs on tarantulas to be very educational and informative. I find tarantulas to be extremely fascinating creatures and would like to maybe get involved with possibly raising them and breeding in the future for profit. Anyway, thanks for all your posts. Andy.

    Reply
    • Thanks Andy! Raising tarantulas is great fun, but it’s worth getting some experience with juveniles and adults before going for spiderlings in my opinion. Spiderlings can be a lot more fragile so a little experience works well.

      Reply

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