Minke whale each side of their mouths. Most of the length of the back, including dorsal fin and blowholes, appears at once when the whale surfaces to breathe. Minke whales typically live for 30–50 years; in some cases they may live for up to 60 years. Minke whales have a digestive system composed of four compartments with a high density of anaerobic bacteria throughout. The presence of the bacteria suggests minke whales rely on microbial digestion to extract nutrients provided by their food. As with most Mysticetes, the auditory system for the minke whale is not well understood. However, magnetic resonance imaging
Creature type (Dungeons & Dragons) all animal type monsters are based on real world animals. Creature entries based on mythological, fictional, or nonexistent animals are usually classified as magical beasts (see below). Besides ordinary fish, birds, reptiles and mammals, the animal type is also applied to depictions of dinosaurs, prehistoric animals, and "dire" or specially modified, often larger and scarier, versions of real world animals. Some real world animals are not given the animal type in the game. Examples include arthropods (insects, spiders, etc.) and worms, which the game classifies as "vermin" (see below) and not animals. Mollusks, such as octopuses, are often classified as