I really had no intention of selecting the correct answer. I've done this before (when the Pants site was alive) - because I'm in a significantly different time zone to most participants it makes it awkward for everyone if I take the chair.
Accordingly I invite someone else to volunteer for the position ... perhaps, as Tuj got us on the right track (sorry) and Chalky the wheels/track, one of them might care to break the champagne and launch the next subject? Please!

Thanks Duj. Nice thought, but I don't feel I made a significant contribution. Perhaps Tuj would like a crack at the next one? If not - perhaps someone else is burning for a turn?

Fine, Chalky. I am unsure as to when Tuj normally posts but perhaps we could all wait until, say, 11;00 GMT on Monday (It's around 01:50 as I type) to allow time for a response. After that time I suggest the 'first in, best dressed' option be invoked.

[Breadmaster/Raak] On the 'bobcat' term: Yes, 'backhoe' is also used here. I suspect that 'bobcat' (well, I'm 90% sure) is a trade name - something like 'Biro' for a ballpoint pen, although the latter term does seem now to be fading somewhat.

Well, neither Tuj nor anyone else has posted. I haven't had a go in the driving seat yet, because I'm not very good at guessing, but unless anyone objects I could have a go, if that's OK with Dujon et al...?

[BM] I was thinking that if Tuj wasn't available - you might take the chair - I say go for it :-)

Excellent. OK. This one is ABSTRACT, but it arguably has both mineral and animal overtones.