Tailless whip scorpions (often called whip spiders), are scientifically referred to as amblypigids because they belong to the order Amblypigi. They have been given the name tailless whip scorpions because of their lack of a tail (telson). In fact, “amblypigid” means “blunt rump”.
Amblypygids are unique in that they have six walking legs, whereas other arachnids have eight. The reason for this is that amblypygids' first “ancestral" walking legs have been modified into sensory organs. These long sensory “feelers” can be twice the length of the body and are used to probe the environment. Because amblypygids are active in environments where there is very little light, these modified “legs” are extremely important to them for sensing their surroundings.
Another distinguishing feature of amblypygids is their pincer-like pedipalps. These structures act like the “claws” of the preying mantis or the mantid shrimp. Amblypygids use them to grasp prey, which are then brought into the body to be sliced by their shearing mouthparts (called chelicerae).