Eros, known as Cupid in the Roman pantheon, riding an animal was a particularly loved decorative motif by the Romans, used in different variants and appearing in different artistic forms, such as intaglio, frescos, mosaics, oil lamps and bronze statuettes. Eros riding a goat or ram can be interpreted in reference to the god Dionysus, or Bacchus for the Romans. In several Dionysian and Seasons sarcophagi dating to the Roman Empire period, Erotes have been portrayed joyfully riding or in the company of goats and rams, perfectly insert in bucolic scenes. Such iconography might be also linked to the cult of Aphrodite Pandemos, who appears riding a goat herself. However, iconographies of Mercury, either in his adult or infant form, riding a goat or ram, have also been recovered, possibly symbolising the entrance of the deity in the realm of Dionysus.PM-47
For more information about the meanings of animals in Roman art, see our relevant blog post:Animal Symbolism in Roman Art.