Quote by Russell Powell

“It is true that neural tissue imposes significant metabolic demands on organisms that natural selection will tend to shed if doing so is beneficial. It is also true that brain size has been reduced in many animal lineages for whom the metabolic costs of cognitive substrate outweigh the benefits of enhanced cognition. This is poignantly illustrated by secondarily herbivorous vertebrates (like panda's) whose calorie-frugal diet can no longer sustain their carnivorous clade's historical brain tissue expenditures. It is the case as well for lineages whose ecology calls for the reduction of neurologically demanding somato-sensory functions, such as 'cavefish' - several groups of freshwater fish adapted to lightless underground habitats that have repeatedly lost portions of the cortex dedicated to visual processing. The loss of a complex head is thus not totally inconceivable.”

Quote by Russell Powell