The Taalo are a race of rock like beings, which, although sharing a base of silicon with the Chenjesu, are very little reminiscent of them.
The only clue to what their physiology was like is given in a conversation with the Dnyarri. "They were nothing more than thugs, especially the hideous Taalo. Those evil rocklike creatures were the worst of all! For fun, they would take one of our children... and then... roll over it!... again and again." From this, it can be assumed that the Taalo were capable of rolling in some manner. Whether or not this was their primary means of locomotion is unknown.
The Taalo were the first sentient race to encounter the Ur-Quan, and enlisted them into the Sentient Milieu. They were the only race that did not invoke the Ur-Quan's inherent territoriality, and the two species became close friends. They were immune to the Dnyarri Psi powers, so the Dnyarri forced the Ur-Quan to destroy them. The Taalo frantically attempted to build a device that would grant the Ur-Quan the same Psi-defense but before they could announce complete success, they were attacked and destroyed by the Ur-Quan Fleet. For a long time, the Taalo were thought to be extinct. However, speculation has some believe that the Taalo still live. They were the only race of the Sentient Milieu (that we know of) that lived in the SC2 starmap's area. The Taalo may well still exist in some form, as the Orz refer to them in the present tense. It is possible that they were using some sort of Interdimensional Fatigue devices - When the Androsynth colonized the same area of space they were not known as interdimensional researchers and yet shortly after the end of the first war, the Androsynth disappeared, leaving evidences of Interdimensional Fatigue Experiments. Even if the Taalo do not exist, some of their artifacts may remain in their home star regions.