I had some elephants that would appear on my map every so often, but they were naturally scared of dwarves it seemed. This is perhaps justified as evolutionary behaviour, because one year a caravan guardsman shot one, puncturing it in several places and causing the poor beast to bleed copiously. However being an elephant, they contain a lot of blood.
Since military doesn't properly work yet, the bloomin' thing was left to wander around my biome for about a whole year, quite literally staining the entire land red - a mark which still persist to this day and can only be cleansed by lava*. One of its friends was captured in a trap, whereupon Bleedy & co. became inquisitive and started poking around my fortress, perhaps in an effort to find their elephantine colleague, cowering away at the first sight of the resident evil dwarves and their magic bleedy-sticks.
Determined to press on they had practically free range of my fortress, while my dwarven military were stood around either trying (and repeatedly failing) to pick up nearby socks, on breaks, or trying to conduct individual combat drills, but in any case they were still terrified of the local fauna (a situation that early earned the local captain his nickname "Ohnoes McWarthog").
Eventually they came across a room with an injured miner, and perhaps seeing red and remembering that painful event with the caravan a year earlier (they do have long memories!) the bleeding elephant decided to attack and kill said resting, defenceless dwarf, before being scared off by some local passers-by - who were more concerned about getting a drink than investing the screams for help from one of their friends' room. (It is well known that a thirsty dwarf can communicate this feeling telepathically, but when he's being attacked by a huge pachyderm feelings of pain must be suffered in silence.)
Finally, cage traps were set, and perhaps noticing that he now had both a weapon and armor rack assigned to form a baracks - or was it tedious mashing of keys that somehow, wonderfully, magically woke my military up to the fact that there were giant hostile creatures literally in front of them terrorising everybody - the beasts were eventually subdued, with the help of a host of war bears.
Elephant McBleedy died of blood less several months later whilst still confined to a cage, roughly at the same time as a fellow herds-creature gave birth to three calves, who later grew up into some quite fine warlephants.
* In a somewhat related incident that involves trying to melt elephants, no-one told me that nickel floodgates and steel mechanisms are now "use-once" in magma. I've got lava streaming down the side of my volcano, perhaps as nature intended, with no way to quench it.
** I've also got myself into a very sticky situation by building my trade depot underneath a magma reservoir. Now it's full of molten cheese - dwarven fondue?