There are two kinds of Javelins: the double-ended kind favored by the otters of Mossflower, and the short throwing missiles used by the Fur and Freedom Fighters.
The otter javelin is made entirely out of wood save for a grip of bark, cord, or leather. They are double-ended, and are usually used for throwing but can also be used for melee combat. They are generally about as tall as a full-grown otter, but are very light and thin to keep the weight down.