Jerison (1973) has suggested that the degree of brain encephalization (the ratio of brain size to body size, EQ) may correlate with an animal’s intelligence and cognitive skills. Corvids and psittcaids have higher EQ than other bird families, similar to that of the apes. While among the Corvidae, ravens possess the largest brain to body size ratio. In addition to the high EQ, the Corvid’s intelligence is boosted by their living environment. First, Corvids were found in some of the harshest environments on Earth, where surviving requires higher intelligence and better adaptations. Secondly, most of the Corvids are omnivorous, suggesting that they are exposed to more different stimuli and environments. Furthermore, many Corvids species live in a large family group and demonstrate high social complexities.