Lions are the only cats that live in permanent social groups. A pride is typically a group of related females with their young and a small coalition of males, and the females do the majority of the hunting while males defend territory against other coalitions. Takeovers by new males are usually followed by the killing of unrelated cubs, which brings females back into oestrus. This is well documented and it sits awkwardly with the lion's symbolic career as a figure of noble sovereignty.
The mane is the only pronounced sexual dimorphism among cats. Field research in the Serengeti has associated darker and fuller manes with higher testosterone, better condition and greater success in both female choice and male contests, though mane development also varies with climate, lions in hotter regions grow less of one, and the maneless males of Tsavo are a well-known case.
The lion is one of the four living creatures of Ezekiel 1 and Revelation 4. In the Western standard, which descends from Victorinus of Pettau through Jerome, the lion belongs to Mark, on the reasoning that his gospel opens with a voice crying in the wilderness. That assignment is not the original one: Irenaeus, around 180, gave the lion to John and the eagle to Mark, and Augustine gave the lion to Matthew. At least three patristic schemes competed and one won, which is worth knowing before quoting the familiar arrangement as though it were fixed from the beginning.
Astrology. Leo is a zodiac constellation catalogued by Ptolemy, associated with the sun in the classical planetary rulerships. The regulus star at its heart, the little king, was one of the four royal stars of Persian astronomy.