Well, everyone needs hobbies. Gerald's are simply stranger and more complicated than the average human's. I'm still in awe he managed to bring about such great changes in just a few generations, back when he was still human. (This level of multitasking must've been insane!)

Remind me to poke you about cross-species reproduction when we get towards the middle of CoS and discuss the Iezu. *snickers*

Yeah, humans will have sex with anything given the opportunity, and that's a fact. ^^;;;

That said, given all of the above it's almost more surprising the early colonists didn't take rakh as pets.

We don't know that they didn't. Though I figure it would be mentioned, if this were a wide-spread practice. Or perhaps the author didn't plan this far ahead/found it was not relevant to the plot.