One World, Many Minds - Intelligence in the Animal Kingdom

Evolution may not be as linear as it was perceived before. New research are finding startling evidences that there are multiple evolutionary lineages, especially, in the development of complex cognitive sophistications. Fish, reptiles, vertebrates and invertebrates may have more intelligence than the "supreme" human beings ever considered to these "inferior" species to have.
"One of the most common misconceptions about brain evolution is that it represents a linear process culminating in the amazing cognitive powers of humans, with the brains of other modern species representing previous stages. Such ideas have even influenced the thinking of neuroscientists and psychologists who compare the brains of different species used in biomedical research. Over the past 30 years, however, research in comparative neuroanatomy clearly has shown that complex brains—and sophisticated cognition—have evolved from simpler brains multiple times independently in separate lineages, or evolutionarily related groups: in mollusks such as octopuses, squid and cuttlefish; in bony fishes such as goldfish and, separately again, in cartilaginous fishes such as sharks and manta rays; and in reptiles and birds. Nonmammals have demonstrated advanced abilities such as learning by copying the behavior of others, finding their way in complicated spatial environments, manufacturing and using tools, and even conducting mental time travel (remembering specific past episodes or anticipating unique future events). Collectively, these findings are helping scientists to understand how intelligence can arise—and to appreciate the many forms it can take."
Read Paul Patton's well written article from the following link in Scientific American.