Final answer:
Fake Killer Whales are actually aquatic mammals, and though their name includes 'whale,' they are a species of dolphins. They are not characterized by black and white coloration, do not primarily eat plants, and are not the smallest marine mammals.
Step-by-step explanation:
A characteristic of Fake Killer Whales (Pseudorca crassidens) is A. that it is an aquatic mammal. Despite their name, Fake Killer Whales are a species of dolphins, which is a group within the order Cetacea, making them marine mammals and not fish. They share similarities with other cetaceans, such as killer whales (orcas), but they are known to have different behaviors, social structures, and diets, which vary from other dolphins and whales. They are not known for a black and white coloration, they are not herbivores, nor are they the smallest of marine mammals.
It is important to note the adaptation of cetaceans, where mammals evolved to live on land and then transitioned back to living in the ocean. Whales, dolphins, and porpoises adapted from land-dwelling creatures to a life fully aquatic, indicating a remarkable evolutionary journey.