Eel-bird

The giant eel-bird was a creature native to the planet Regulus V. The eel-bird must return to the caverns from which they were hatched every eleven-years in order to mate.

Like the salmon, Spock referred to the eel-bird while attempting to explain the Vulcan mating ritual pon farr in 2267. 

Aal-Vogel Uccello-anguilla ウナギ鳥