Final answer:
The jaguar is the most frequently depicted animal in Olmec artwork and is associated with shamanistic transformation into were-jaguars.
Step-by-step explanation:
The animal most frequently depicted in Olmec artwork and associated with shamans who could transform into a half-human, half-animal being is the jaguar. Olmec art and mythology often represent the were-jaguar, which is a supernatural creature embodying the characteristics of both a jaguar and a human.
This signifies the jaguar's importance as a powerful entity within Olmec culture, as they blended the attributes of the mightiest terrestrial predator with human form, indicating a link to the spirit world and shamanistic practices.