The remote Ankarana preserve within the island of Madagascar, a few hundred miles away from the coast of Africa, shelters an impressive assortment of exotic wildlife. Protected using a fortress of ancient coral mountains with forbidding razor-sharp spires, a few of these unusual creatures have thrived unscathed and unchanged for centuries. Aggressive Nile crocodiles, incredibly rare crowned lemurs, countless chameleons, and also the lethal fossa, identified as a ''mongoose on steroids,'' share the lush forests and deep, forbidding caves of Ankarana.