Below 100.0 Animal Lore, you can
only lore tamed creatures (so only tamed Greater Dragons).
Once you reach 100.0 Animal Lore, you can lore any tameable creature (in addition to tamed creatures).
Once you reach 110.0 Animal Lore, you can lore any creature (provided it is not a human; such as brigands, wandering healers, etc..).
You can find more information here:
Animal Lore.
Jewelry can be used to augment your skill. Using jewelry will allow you to lore creatures that you could not normally get information on, provided it brings you up to the minimum required skill for what you want to lore (listed above). I have used jewelry on my stealther to scout for greaters.
Stayin Alive,
BG