Rooby: Do spiders eat naughty spiders?
Me: Hmm. I don’t know if spiders usually eat other spiders. But you know what does like to eat spiders?
Rooby: But that is not nice! If birds eat all the spiders then who will eat the naughty bugs that bother us?
Me: I don’t think the birds will eat all the spiders.
Rooby: Oh right. Because then they would have a spiderache.