Nyx. Parts of this frieze have been vandalized.
nocturnal
According the Greek story of creation, at first there was nothing but Chaos. Chaos was a huge, wild, disorganized void or nothingness. Chaos had two children: Nyx and Erebus. Nyx and Erebus were not gods to be worshipped; they were personifications of the concepts of night (Nyx) and darkness (Erebus).
Nyx laid an egg, and from it came Love. When Love was born, beauty and order came, too. The confusion of Chaos began to disappear. Love created Light and Day.
In some stories, Nyx rode across the sky in a chariot, bringing night.
The Roman name for Nyx was Nox, and our English words come from Nox.
When would you expect to see a nocturnal animal?