Of Man and Manta

Of Man and Manta is a trilogy of science fiction novels written by Piers Anthony.

The trilogy consists of the three books Omnivore (1968), Orn (1970), and 0X (1975).

Omnivore has as its frame the investigation of the deaths of eighteen travellers from Earth to the distant planet Nacre'. We see Nacre through the eyes of three surviving scientist-explorers – Cal, a blood-drinker, Veg, a vegetarian, and Aquilon, an omnivore.

Nacre is a planet whose dominant species are fungi, including the intelligent mantas. The mantas take the form of soft bodied creatures capable of high speeds and flight, resembling the manta rays of Earth superficially. They are carnivores, who farm the one extant herbivore species by protecting them from the voracious omnivore species. The planet is notable in its thick atmosphere, which allows flight to be performed with less energy, and permits the existence of air-borne phytoplankton. The herbivores eat the plankton, and the omnivores eat anything they can.

Orn involves travel by the scientists and mantas into a parallel dimension resembling they dub Paleo, resembling the distant past of Earth, where they encounter dinosaur species and an intelligent flightless bird called Orn. Orn has the ability of racial memory, able to remember anything that that happened to an ancestor prior to the time of their reproduction. Much of the plot conflict stems from the love triangle between the protagonists and the mysterious motives of a cybernetically-augmented government agent sent along to moniter their progress.

OX involves the three scientists attempting to return to Earth from another dimension inhabited by hostile machines. Interlopers from other realities (using technology similar to that of the scientists' government) guide and hamper the explorers. A secondary story tells of a multidimensional cellular automaton energy being named OX and its attempts to share living space with a infant human male, a fledgeling creature of Orn's species, and one of the manta-carnivores; their developing relationship leads to attempts to learn the reasons for their strange isolation from others of their kind, which eventually ties in to the story of Cal, Veg, and Aquilon.