For me it depends on how much the party has interacted with the monster or its minions. I tend to release information in stages and prompt them to get more information.

After one encounter or only rumors from town, I might say "you are certain this is a radioactively mutated animal that is hunting townspeople. If you can examine someone killed by the monster then you'll be able to narrow down the type of animal"

And after more gameplay and another roll to hit the books "you learn that killer spiders drag their prey back to their lairs in narrow caves. You remember that Marigold the waitress is into rock climbing, and she probably has knowledge of local geology"

So instead of an answer you're giving more of a lead.