If you visit the Horse page, you'll see that Joy's horse is called Kira. This is after Kira Nerys, a character in Star Trek: Deep Space 9.
We read a couple of books on Fancy Rats before taking the plunge, and decided to buy a female. By this time, I had already decided to call the rat Odo. Odo is a changeling in DS9 (and technically, therefore, neither male nor female), and has a relationship with Kira.
When we went to look for our rat, Odo's markings made him look as though he was wearing a tuxedo. It was fate - in the last episode of DS9, Kira admits to Odo that she likes him best in a tuxedo. He was also the cheekiest and friendliest.
After he'd been with us for two days, he seemed more subdued, although happy when we were paying him attention. At this time, I found the National Fancy Rat Society website. This contradicted the books I had read, and strongly recommended buying two rats, as they are very social animals. Everything I read at their website made so much sense and I spent an agonising night waiting to see if his sisters had been sold. They had not!
We bought Buffy (named after the Vampire Slayer). She is much quieter and sweeter than Odo, who delighted in climbing up everything, only to find he couldn't get back down. Both were loveable in their own special ways.
And why "he" for Odo? Convenience. It was easier to say "he" and "she" than refer to them by name, all the time.
For those of you who can't understand why anyone can love a rat - they are clean, affectionate, never bite, and are very intelligent. Unlike hamsters who bite, and can't work out why the scenery doesn't change, no matter how hard they run!
I read somewhere that rats would be the most popular pet in Britain, if only they had short furry tails. They have a lot of (undeserved) bad press. I only know that we would never be without them.