With regard to the carnivorans, the character "tail" has two states. In this phylogenetic analysis, an elongated tail is the ancestral character state (scored with a 0) and a short tail is the derived character state (scored with a 1). In phylogeny A, a short tail is hypothesized to have evolved after the split between otters and the taxa of bears, sea lions, walrus, and seals. This relationship proposes that a short tail is the synapomorphy for the monophyletic group of bears, sea lions, walrus, and seals. In phylogeny B, a short tail is hypothesized to have evolved twice, exhibiting homoplasy. A short tail here is a derived trait for the seals, but it is also a shared derived trait for bears, sea lions, and walrus. However, there are a few separate divergences between seals and this group, and the common ancestor is hypothesized to have an elongated tail. In phylogeny C, a short tail is hypothesized to have evolved twice as well, but then was lost in one lineage branch. A short tail is a derived trait for the bears, but it also initially evolved as a shared derived trait for taxa of sea lions, walrus, seals, civets, hyenas, and cats. Cats, hyenas, and civets then lost this short tail, demonstrating an evolutionary reversal. In phylogeny D, a short tail evolved once in the lineage to include the monophyletic group branching from seals to dogs, but it was lost later in the taxa of otters, raccoons, and dogs, exhibiting another evolutionary reversal. Based on this trait and the parsimony principle, phylogeny A is the most likely evolutionary hypothesis as the tail trait only evolved once in the lineage and was not subsequently lost. The parsimony principle guides us to the evolutionary tree with the fewest character-state changes, which is usually regarded as the best.