"Beneath the giant head of the Jaguar God that crowns the western stairway are two dancing Waterlily Jaguars that flank it at the stairway's base. They seem to function as zoomorphic adjuncts or avatars of the anthropomorphic deity framed by Venus symbols...In various contexts, the Waterlily Jaguar appears marked with k'in signs, suggesting he personifies the Sun, but a few pottery vessels also show him in a form consistent with the representation from the East Court stairway, that is, with Venus symbols that shine from his entire body. The Dresden Codex god seems to be linked to solar and lunar eclipses, and bears a title distinguished by a k'in infix rather than a Venus sign. The jaguar deity may have had overlapping or dual roles concerning the Sun and Evening Star, and his simultaneous association with both celestial bodies appears consistent.
It is difficult to understand how the Maya conceived of this connection between Venus and the Sun. Schele and Miller point out that the inconsistencies also extend to the interpretation of GI, who at times appears in contexts where he seems to signify the Sun rather than Venus. The close relationship between the celestial bodies, as Venus constantly hovers near the Sun, apparently suggested to the Maya that the two were joined in some mystical union. Rather than presenting an unresolvable contradiction, the iconographic evidence suggests a complex astrology of omens and apparitions in the skies, as well as a more fundamental level of mysticism entwining the fates and personalities of the Hero Twins than Mayanists previously suspected."
Elizabeth A. Newsome, Trees of Paradise and Pillars of the World: The Serial Stela Cycle of 18-Rabbit-God K, King of Copan, p. 119-122
NOTE: According to Schele, the round indentions on the jaguars' bodies were originally rendered with inset obsidian disks to represent spots on their pelts.