Gregorias are marine animals black neck striped with white and living on Aldebaran-4, recently identified as one possible form of Mantris. Though it is possible that the Mantris simply eats the creatures!
Almost nothing is known of them. They lives in large groups of several hundred's of individuals feeding on fish. Herds only include adults with no young amongst them. They are listed in the catalogue, they are seen only by chance and very rarely, fishermen encounter herds of these creatures in a following a cycle of 10 in 10 years