Book Reviewed: Many Things Under a Rock: The Mysteries of Octopuses by David Scheel

The inner lives of octopuses Octopuses are invertebrates that lack skeleton, and their legs have no femur, tibia or fibula, no feet, and no toes to wiggle. Instead, octopuses have a hydrostatic skeleton, combining muscular contraction and water's resistance to compression, to generate movement. The octopus genome illustrates how intelligence evolved in this animal. With its eight prehensile arms lined with suckers, camera-like eyes, elaborate repertoire of camouflage tricks and spooky intelligence, the octopus is like no other creature on Earth, which explains the evolution of their cognitive skills. The octopus’ genome is as large as a human, and they contain a greater number of protein-coding genes than Homo sapiens. One of the most remarkable gene groups is the protocadherin, which regulates the development of neurons and the short-range interactions between them. The octopus has 168 of these genes more than twice as many as mammals. This resonates with the creature’s unusually large brain and the organ’s even-stranger anatomy. Of the octopus's half a billion neurons, two-thirds spill out from its head through its arms, without the involvement of long-range fibers such as those in vertebrate spinal cords. This gives independent computing power to its arms. They have more autonomy than human arms. Each has its own miniature brain, giving it a degree of independence from the animal's central brain. On the contrary, the human’s nervous system is highly centralized, with the brain as the seat of sensory integration and other actions. They are the closest we will come to meeting an intelligent alien. The author narrates his experience as an explorer of octopus in its natural habitats off the coasts of Alaska, Washington State, and Japan. This book does not explain the octopus’ biology or physiology but discusses from a behavior ecologist’s perspective. Octopus is a nature’s wonder, because this soft and boneless aquatic species survives with otherer formidable animals like sharks, killer whales, and eels. How do they hunt while avoiding danger in the ocean? Their anatomical structure, skills, camouflage, and a unique nervous system that matches human consciousness.