PEEC Amateur Naturalist: Arachnids At HalloweenHalloween is here. Two kinds of arachnids are ideal candidates to scare us in the dark, although they are harmless to us for the most part. They may cause some trouble only if we go out of our way to annoy them, causing them to defend themselves.
Tarantulas are the first candidate for Halloween. They look big, hairy, and scary if seen at night. Some tarantulas can grow to be large. The Chaco Golden Knee tarantula may grow to be about eight and half inches in length. The Chaco Golden Knee tarantula is native to Argentina and Paraguay. In spite of this size, it’s particularly docile when held gently.
Halloween greetings from a mature Chaco Golden Knee tarantula. Photo by Robert Dryja
A young Chaco Golden Knee tarantula at rest. Photo by Robert Dryja
Tarantulas appear to have two “eyes” if you look casually at their head. However, they actually have another six smaller eyes. These are in two sets of three on either side of the two larger eyes. All these eyes together are better called an ocular tubercle or eye turret. If something large with eight eyes walks by you in the dark on Halloween eve, you may be looking at a tarantula.
Impressive as tarantulas are for Halloween, vinegaroons are even more so. ike tarantulas, vinegaroons have four pairs of legs. However, the front pair is much longer than the others and acts like feelers for whatever is front of it. Vinegaroons also have a long tail that looks like a whip. The tail provides a sense of touch for whatever is above or behind it. Vinegaroons are about two and half inches long when grown but can appear much larger when they extend the front legs and tail.
Tarantulas have an impressive set of pedipalps (appendages that help them grab and eat their prey) and fangs at the front of their heads. However, these look small when compared to those of vinegaroons. By contrast, the pedipalps of vinegaroons seem to be huge claws.
Rather than defending itself by biting, a vinegaroon may spray concentrated acetic acid — vinegar — from a gland located at the base of the tail. The spray can be directed with some accuracy or be spread around. Do remember that vinegaroons are calm and docile. They spray only to defend themselves when feeling threatened and unable to hide or escape. Vinegaroons are active at night, and only insects need to be concerned about being eaten. So if you smell vinegar while out and about on Halloween eve, you may have disturbed a nearby vinegaroon that only is looking for dinner.
A vinegaroon having a sip of water after trick or treat. Photo by Robert Dryja
