So after my earlier encounter with some mandrills, I fire up a new Play Now! settlement to see what happens (previously I'd been trying to pick out a reasonable 'calm' site).
Barely a minute passes before I notice a wave of 'm' creatures approaching - this time not mandrills, fortunately (I don't remember what they were... some two-word name), but nevertheless they were apparently quite intent on ransacking my outpost before I'd even dug into the mountainside!
As an emergency, I allocate all my dwarves into a single squad and activated them. My new ultra wrestling force had no problem dealing with the situation, so I then deactivated the squad so they could get back to their normal business. Except...
Another wave of m's came. And another. With this new tactic of defence they were no threat, but by having to activate and deactivate the squad so frequently, the dwarves became unhappy at being relieved from duty.
Not only that, but for some reason my axe-using Carpenter / Woodcutter dwarf seemed to be unable to chop trees after all the wildlife had been dealt with. I notice some equipment gets dropped upon squad deactivation, so maybe that's what happened to his axe (I think I'd set all members of the squad to fight with axes). Unfortunately he didn't seem inclined to go and find it again to get on with his proper job.
End result: lots of butchery materials but no wood to make barrels to keep them in (or even some beds to rest my disgruntled beardies)