The Deer without a Heart is an ancient fable

Fable

A fable is a succinct fictional story, in prose or verse, that features animals, mythical creatures, plants, inanimate objects or forces of nature which are anthropomorphized , and that illustrates a moral lesson , which may at the end be expressed explicitly in a pithy maxim.A fable differs from...

, attributed to Aesop

Aesop

Aesop was a Greek writer credited with a number of popular fables. Older spellings of his name have included Esop and Isope. Although his existence remains uncertain and no writings by him survive, numerous tales credited to him were gathered across the centuries and in many languages in a...

, about a deer (or an ass in some versions) who was persuaded by a wily jackal

Jackal

Although the word jackal has been historically used to refer to many small- to medium-sized species of the wolf genus of mammals, Canis, today it most properly and commonly refers to three species: the black-backed jackal and the side-striped jackal of sub-Saharan Africa, and the golden jackal of...

to visit the ailing lion and thus to ingratiate himself with the sick king of the animals. The lion killed the deer. The jackal stole and ate the deer's heart. The lion suspected the jackal of the theft, but the jackal argued that a deer who was so foolish as to visit a lion in his den must be without a heart. The fable reflects the ancient belief that the heart was the seat of thoughts and intellect. This belief has long since been discarded and modern versions often replace the heart with the brain.