Sunday, July 24, 2011

Costa Rica Day 11 – Wandering spiders

Ctenidae is a family of moderate to large spiders which dominate the spider fauna in Costa Rica, much the same way as the Sparassids (huntsmen) do in Australia. Ctenids are known as wandering spiders and have a very distinctive eye arrangement; they basically have a row of six across the top and two below. Viewed from the front they have four large forward facing eyes which make them quite easy to identify.
Cupiennius sp.
A large ground-dwelling Ctenid

Another large ground dweller we have nicknamed the 'Leopard  wandering spider  due to the spots on the legs.
Some species are very much like huntsman in their hunting methods and speed of movement, whilst others hunt on the ground and are more like over-sized wolf spiders. As their common name suggests, they tend to be wanderers, although I have noticed that some species tend to favour a territory and I will see them each night in much the same place. Their hunting technique basically relies upon ambush; pouncing on their prey with speed and power. So far I have witnessed them feeding on moths, katydids, other spiders and frogs.

A Ctenid spider feeding on a katydid

There are a number of large species around the Osa Peninsula, and we have encountered four here where we are staying. One of the most notable is known a Brazilian Wandering Spider (Phoneutria reidyi). It is a very large spider and has extremely potent venom. I have already heard several stories of locals being hospitalised in excruciating pain from the bite of this species. I have found two of these spiders in my boots, and on one occasion I was just about to slip my bare foot in when I spotted it.
Phoneutria reidyi

Another common Ctenid is the Red-thighed wandering spider (Cupiennius sp.) This is the size of a large huntsman, but more unpredictable in its movement and believe it or not, even faster than most huntsmen I have worked with. We used this species in the studio recently, and it was challenging to keep them on the set and off my back.

Cupiennius sp.
One of the surprising aspects to this family is the variation within egg sac form. Some of the species (Phoneutria spp.) produce a domed sac, that is secured to a flat surface. Others (Cupiennius spp.) create a round sac and trail it behind them as Lycosids do, while others carry the sac with their fangs.


  1. It's great to hear your updates... I hope you are checking your boots every morning now... just in case!

  2. These wandering spiders are so beautiful! Yeah, we get them in our house sometimes. I live in the eastern lowlands of the Caribbean in Costa Rica. What remarkable spiders and how lucky we are to have them! Muy bueno!

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  4. Thanks for sharing this info. I know it's an old post, but these are awesome photos. Just remembering about a set of spiders who showed-up in our poorly enclosed bungalow, when my brother and I were visiting Costa Rica at the edge of a tropical forest at some point in the 1990s. My memory was sparked after randomly coming across these images. It looks like we were visited by wandering spiders, either in the family Ctenidae or Sparassidae. Though it could have been, Phoneutria fera, which I've read are extremely aggressive with potentially deadly venom. At the time we did not know this, but debated long and hard about what do with these spiders, not to mention the dozens of other forms of unidentified insect life we came across in the room. That was the night I learned the importance of closing windows or at least window screens, rather than just open wood slats on in the bathroom "window".

  5. How bad is the venom of the other wandering spiders