These truly remarkable animals are commonly known as TAILLESS WHIP SCORPIONS and are possibly my favourite group of arachnids in the world!  Whilst they are arachnids, like spiders and scorpions, they are neither true spiders or true scorpions but a distinct group known as the amblypygids.  This particular species is native to Tanzania in east Africa.  The pictures below are of my adult pair and I have named them Bob and Kate!

Their spiny pedipalps or 'pincers' are of a very different structure to the scorpions although like scorpions they are still used to catch prey.  When a whip scorpion is at rest, as in the first picture below, these pedipalps are folded in on themselves and are a bit like arms fully bent at the elbow:

When the whip scorpion is disturbed, or when it is hunting, these pedipalps will be opened up ready for action, as in the picture below:

You can easily tell males from females in this particular species of Tanzanian tailless whip scorpion because the males have much longer pedipalps.   In the pictures below Bob the male is on the left, with pedipalps which extend beyond the first 'knee' joint of the legs, whereas Kate's (on the right) do not:

You can also see this difference in this picture of the two of them together, again with Bob being on the left hand side:

In the picture below you can see that Bob & Kate's front legs are much longer and thinner than their other legs.  These front legs are actual special sensory legs and are not used for walking, whereas the other six legs certainly are used for walking (or running)! 

These front sensory legs are very thin indeed and have lots of sensory receptors, so that when they are used to probe around as they walk through their habitat they can detect the tiniest vibrations or movements made by potential prey items before the pedipalps are used to grab them! The picture below shows just how long they are, with none of the sensory legs even fitting fully into the frame of the picture!

Whip scorpions, like all arachnids, have to moult their exoskeletons regularly during their development.  In August 2010 Kate moulted and I was lucky enough to get some pretty amazing photographs of her soon after finishing!   I was just doing my usual late evening checks of all my animals when I noticed what I thought was Kate hanging upside down inside her enclosure:

On closer inspection I realised that this was not Kate herself, but her empty old exoskeleton (or exuvia)!  She had managed to leave it completely in one piece and as you can see below it looks just like her, despite being nothing more than an empty old body which is no longer required!  The first picture below shows the 'head' (carapace) of the exuvia closed, the second picture shows it opened and the third shows the underside of the exuvia: 

As you can see it is really quite a remarkable structure and it is preserved perfectly.  Taking a closer look at the exuvia once the pedipalps have been opened you can see clearly the very sharp spines which are used in hunting:

Despite looking as if it is suspended in mid-air in the pictures above and below, the flipped-open carapace is actually connected to the abdomen via a very small and thin structure called the pedicel!  It looks pretty cool though, hope you think so too!

When some arachnids have just finished moulting their appearance can be quite different to usual, as the new exoskeleton is soft and also needs time to dry out.  I was amazed when I found Kate sitting on a piece of bark in her enclosure, because her appearance was just incredible as you can see here!

With her soft green/blue body she looked even more like an alien than usual!!  Amazing.

Compared to Bob, on the right below with the normal dark brown/black colour, Kate sure looks really odd!

Whilst whip scorpions may look incredibly fearsome they really aren't at all!!  I personally handle these very regularly without any concern about being injured, as unlike scorpions they are not venomous and they are non-aggressive.  I also allow children to handle them as demonstrated here by 8-year old Ethan at his birthday party! 

I'm sure you'll agree that tailless whip scorpions are quite amazing creatures, which in many ways are quite alien in their appearance, and you can trust me when I say that in the flesh Bob & Kate are even more amazing!