Why wait?

So I've been reading Watership Down for a while now, and one thing I noticed was that those rabbits seem to do everything as soon as they decide on it, or at least pretty quickly afterwards. This includes large, difficult plans, such as Bigwig's infiltration operation in Efrafa and extracting the does from the farm. Why, I thought, do they not wait and talk things over for a bit longer? Why is always "we've got a plan, now let's act on it".
Then I started thinking about a theory we were told by Simon Verhulst when he introduced the book we're translating for a course. He argued (pretty convincingly), that when you know (and this includes non-conscious "knowing", obviously) that your life isn't going to be that long, you'll invest in the moment. You'll go the extra mile, make the extra baby, fight the extra enemy, because tomorrow you may be dead. This is what we called the "mouse-strategy" when I was studying biology; live fast, make lots of babies, die young. Now when you're like us humans, and you can expect to live for around 80 years, you don't have to start making babies as soon as you're able to (although some 14-year-olds still do), you can first get a degree and a job and a nice house and a partner that isn't going to run away any time soon before you make your big investment. And of course related to this, that investment is that much bigger, because rabbit kittens (to stick to that example) can leave their mother when they're about 4 to 5 weeks old, and we tend to stick around until we're 18 years.
So there is a point to this "act in the moment" behaviour. Somehow it puts me in mind of "Don't stop thinking about tomorrow", which is one of those songs you've heard a thousand times but never realised what it is actually about. But I think both rabbits and Fleetwood Mac have a point. Tomorrow is going to be here soon enough, what's the point in sitting around weighing your options, just go for it, and see how far you get (or as they say in Dutch: see where the ship beaches). We're still on the "elephant-strategy", to be sure, so I wouldn't advise this for long-term things like having children or sailing around the world, but a little more spring-of-the-moment acting may not be such a bad thing. Worked out pretty well for the rabbits.