Common minke whale to 20 growth layers in their tympanic bullae, which may correspond to about 15 to 20 years of age. Both sexes can live to about 50 years of age – the oldest in a study of Icelandic minke whales were 42 years for females and 47 years for males, respectively. Common minke whales have been described as ichthyophagous, but their diet also includes pelagic crustaceans and cephalopods and varies by region, season, and year. In the North Atlantic, they primarily eat small schooling fish, demersal fish, and krill. A 2007 study showed that off Spitsbergen they fed almost exclusively on
Creature type (Dungeons & Dragons) animals despite their real-world bases being more closely related to vermin type creatures. Creatures deemed inconsequential by DMs or designers are not given any creature type at all, instead being treated as "set dressing" unless a specific game effect targets such non-creatures. Examples include actual-sized spiders, sparrows, fleas, worms, shellfish, and mice. "Swarm" type creatures are occasionally written to represent such otherwise nonthreatening creatures if they were to group together by some force of magic within the game world. Under the rules of D&D, animal type creatures do not have an Intelligence score higher than 2. When a designer makes