The Spindle Neuron is why whales, dolphins, great apes and elephants are truly special

and should not be harmed for food, recreational killing, enslavement, or production of trinkets.

Spindle neurons, also called von Economo neurons (VENs), are a specific class of neurons that are characterized by a large spindle-shaped soma, gradually tapering into a single apical axon in one direction, with only a single dendrite facing opposite. Whereas other types of cells tend to have many dendrites, the polar shaped morphology of spindle neurons is unique. They are found in two very restricted regions in the brains of hominids – the family of species comprising humans and other great apes – the anterior cingulate cortex (ACC) and the fronto-insular cortex (FI). Recently they have been discovered in the dorsolateral prefrontal cortex of humans.[1] Spindle cells are also found in the brains of the humpback whales, fin whales, killer whales, sperm whales,[2][3] bottlenose dolphin, Risso’s dolphin, beluga whales,[4] and the African and Asian elephants.[5] The name von Economo neuron comes from their discoverer, Constantin von Economo (1876–1931) who described them in 1929.[6]
The observation that spindle neurons only occur in a highly significant group of animals (from a human point of view) has led to speculation that they are of great importance in human evolution and/or brain function. Their restriction (among the primates) to great apes leads to the hypothesis that they developed no earlier than 15-20 million years ago, prior to the divergence of orangutans from the African great apes. The discovery of spindle neurons in diverse whale species[3][4] has led to the suggestion that they are "a possible obligatory neuronal adaptation in very large brains, permitting fast information processing and transfer along highly specific projections and that evolved in relation to emerging social behaviors."[4]p. 254 Their presence in the brains of these species supports this theory, pointing towards the existence of these specialized neurons only in highly intelligent mammals, and may be an example of convergent evolution.[8] Recently, primitive forms of spindle neurons have also been discovered in macaque monkey brains.