I haven't read the book, but I remembered seeing the original picture on a website somewhere, a long time ago. It took a bit of Google-fu to trace it back.
BTW, its hand-walking is probably based on the fact that vampire bats use their powerful front limbs (ie their wings) to propel themselves when they run.
The original concept that this... thing... is a parody of was pretty cool, though. An ecosystem made mostly out of bats whose wings have devolved back into arms and legs again, since the niche of top predators was empty.
