The "spiders" of Rubi-Ka are very similar
in body type to their smaller 8-legged cousins, but
are many orders of magnitude larger and have four fewer
legs, a fact reflected in the genera names, which all
begin with the tetra- prefix. Also, with their increase
in size has come a requisite change in the visual and
mandibular structures of the animal's head, with these
"spiders" developing mammalian eyes with color
vision and a stronger, more reptilian jaw structure.
When combined with their retention of a spider's ability
to use toxin in hunting its prey (thus causing chemical
damage to humans confronting them) and their tendency
to operate in small groups, it is easy to see why the
"spiders" on Rubi-Ka are one of the more feared
groups of animals among the newer settlers.
There are five individual genera of "spider"
on Rubi-Ka, which, though similar in overall appearance,
do have significant differences in size, temperament,
speed, and reproductive capacity. Bloodcreepers include
the standard Bloodcreeper, and Boneheaded and Speckled
types. Nightcrawlers include standard, Old, and Ancient
types. Spinners are only known to include the Fearspinner
Gargantulas include the standard, Old, and Ancient types.
Widows are only known to include the Red Widow.
The purpose of spiders in Omni-Tek terraforming regions
is mainly as crowd control: similar to their ancient
Earth ancestors, the spiders of Omni-Tek planets are
used as a check on potential population explosions of
other terraformers, like Stalkers, Scorpiods, and Offals.