Outdoors, when travelling in the wilderness, yes. Part of that is due to the probability of a humanoid with inferior senses tripping over a natural predator in its own habitat, and part of it is due to the way that 5E rules discourage trivial combats by handing out so much free healing.
Even in circumstances where it makes sense for the party to come across a random monster or bandits or something, I'm much more likely to just handwave it, since there's no chance that anyone will die and all damage will be erased by morning. The exception to that is usually dragons, unless the party is over level 10, at which point those can also be handwaved.
That's just a matter of how you want to label it. Generally speaking, if the monster is 20 feet away and the party never sees it, I wouldn't count that as an encounter.How does the predator have a chance to notice the humanoid without encountering it?
Theoretically, yes, but not a significant one. If you have a sleeping leopard in a corn field, and you cross that field at random, your chance of tripping over the leopard is significantly less than five percent.And wouldn't the humanoid then have a chance to notice the predator, however small that chance may be?
That's just a matter of how you want to label it. Generally speaking, if the monster is 20 feet away and the party never sees it, I wouldn't count that as an encounter.
Theoretically, yes, but not a significant one. If you have a sleeping leopard in a corn field, and you cross that field at random, your chance of tripping over the leopard is significantly less than five percent.
Except for things like salt pans, there's rarely terrain that's truly flat. Gullies, dips, etc., exist that can be taken advantage of to move undetected through a lot of 'open' terrain. A dip of just a few feet can be exploited to be invisible. This is even ignoring things like tall grass or other ground vegetation.
To further highlight the differences in our process, I would argue that a sleeping leopard is inherently stealthy, and would require a check to find it even if you knew it was around. A sleeping cat has more in common with a hidden object than it does with an active creature.I think our resolution process differs somewhat. I wouldn't require you to trip over the leopard in order to notice it. Determining that the sleeping leopard is encountered is what prompts me to introduce it in the first place. That determination also tells me the leopard is within encounter distance, and since it's asleep, and therefore not trying to be stealthy, it would be noticed immediately.
To further highlight the differences in our process, I would argue that a sleeping leopard is inherently stealthy, and would require a check to find it even if you knew it was around. A sleeping cat has more in common with a hidden object than it does with an active creature.
It's not a trait of any particular creature. It's just my ruling on the general properties of being asleep, is that you aren't drawing any special attention to yourself.I generally wouldn't use my personal knowledge of leopards to make a ruling that affects a mechanical outcome of the game. I'd rather let the mechanics speak for themselves, and if there's nothing in the leopard's stat-block about being hidden when asleep, then I wouldn't introduce such mechanics to model something about leopards that the stat-block doesn't capture. I don't think a 5e stat-block for a leopard exists, but looking at the panther and the tiger, they have no special ability to remain hidden while asleep.
I don't see why the larger leopard wouldn't be even more noticeable.
And me, I'd have to decide if this specific leopard chose to sleep out in the open or looked for a hiding spot to nap in.Though in the end I agree, without something to say "Leopards are considered hidden even while sleeping..." or similar, I would not impart such a thing. However I might say that so long as the leopard is sleeping in its natural terrain (the jungle) checks to spot it are at a disadvantage.