What You Need To Know About Urticating Hairs

What you need to know about Urticating hairs on tarantulas and how to handle their effects

When looking at your pet tarantula, you will discover its whole body is dominated by hairs. They seem to appear harmless, but there is more to know about them. The main fact about the hair is that it serves as a defense mechanism for tarantulas.

Urticating Hairs


Don’t let those funny looking hairs fool you…   

The hairs are mostly referred to as urticating hairs or urticating bristle. The word Urtica is Latin and it means “nettle” that is hair that stings, just like the ones that can be found in plants such as Urtica dicola. The tarantula spider is covered all over with these nettles ready to sting any external threat.

How does this defensive mechanism work?

Tarantulas at the moment of a danger move towards the threat and release urticating hairs from the body by rubbing its hind legs against its Opisthosoma–the posterior of the tarantula. As these clouds of hairs come in contact to the threat which could be a small mammal, they will seek to reach the mucous membrane of that small mammal and cause edema–It can be fatal.


Latest studies done on the effect of this defense mechanism shows that they can even cause both mechanical and chemical suffering to the victim’s skin and membrane.

Does the effect of urticating hairs vary with the species of the tarantula?

The answer is yes it does….

There are various species of tarantulas out there with each of them having a certain degree of irritation and reaction from their victim’s. Here are the species of tarantulas and/or arachnids to consider when scaling them according to their lethality:

  • Chilean rose tarantula – It is also known as Grammastola rosea. This species of tarantula’s urticating hairs have a minimal effect on their victim, especially to humans.
  • Brazilian giant white knee tarantula – they are also known as Acenthoscurria geniculate. Their urticating hairs have a moderate effect on the victims.
  • Goliath Birdeater – they are also known as Theraphosa blondi. This species of tarantulas have urticating hairs which are severe in effect to the victims. The hairs are so lethal, they are likened to be as sharp as shards of fiberglass and they leave a painful rash on the victims (human) skin.

Please note: as the urticating hairs are released, there will be a bald spot on the tarantula until it develops another set of Urticating hairs.

The effect of urticating hairs on the human skin

The urticating hairs can cause the human victim discomfort on the skin by manifesting skin reactions such as rashes, inflammations, and itchiness. The effect is known to last for long hours and in worse cases, it could take weeks.

How do you treat and handle urticating hairs from tarantulas?

Now that you know the effect of the tarantula, the obvious next step to take is to find a way to prevent them.

When in contact with these hairs, they will cause the victim to endure intense irritation, especially if it is in sensitive places like the eyes or the breathing passage.

Here are what you should do in order to treat or handle the effect of these barbed venomous hairs:

  • Prevent inhaling any loose hairs from the tarantula
  • If any loose hair has been inhaled, it is best to seek medical care because it is very possible for it to reach the lungs
  • Make use of tools like tweezers to pluck out the removable urticating hairs from the skin
  • Apply wax or duct tape on the area of the skin where there are loose urticating hairs on the skin
  • Apply steroid creams for several days
  • Prevent the loose hairs from reaching your eyes
  • Be on the lookout for any symptoms or allergic reactions

Allergic reactions and symptoms to look out for:

  • Headaches
  • Rashes
  • Anxiety
  • Respiratory troubles
  • Abdominal cramps
  • Nausea


So there we go… that’s pretty much the necessary things you should know about urticating hairs as an owner of a pet tarantula or just someone looking understand them.

They serve as a defense mechanism for tarantulas– not to kill, but to help it escape from harm. If you have been stung by their hairs, there are ways to help treat the effects.