Pinniped Pinniped Pinnipeds, commonly known as seals, are a widely distributed and diverse clade of carnivorous, fin-footed, semiaquatic marine mammals. They comprise the extant families Odobenidae (whose only living member is the walrus), Otariidae (the eared seals: sea lions and fur seals), and Phocidae (the earless seals, or true seals). There are 33 extant species of pinnipeds, and more than 50 extinct species have been described from fossils. While seals were historically thought to have descended from two ancestral lines, molecular evidence supports them as a monophyletic lineage (descended from one ancestral line). Pinnipeds belong to the order Carnivora and their
Mammal destruction]], though there are efforts to combat this. [[File:Mammal species pie chart.svg|thumb|upright=1.35|The orders [[Rodent]]ia (blue), [[Chiroptera]] (red) and [[Soricomorpha]] (yellow) together make up over 70% of mammal species. Mammal classification has been through several iterations since [[Carl Linnaeus]] initially defined the class. No classification system is universally accepted; McKenna & Bell (1997) and Wilson & Reader (2005) provide useful recent compendiums. [[George Gaylord Simpson]]'s "Principles of Classification and a Classification of Mammals" (AMNH "Bulletin" v. 85, 1945) provides [[systematics]] of mammal origins and relationships that were universally taught until the end of the 20th century. Since Simpson's classification, the [[fossil