Intelligence of Animals

Comparing the intelligence of animals of different species is difficult, how do you compare a dolphin and a horse? Psychologists have a technique for looking at intelligence that [blank] not require the cooperation of the animals involved. The relative size of an individual's brain is a reasonable indication of intelligence. Comparing [blank] species is not as simple as an elephant will have a larger brain than a human simply because it is a large beast, [blank] we use the Cephalization index, which compares the size of an animal's brain to the size of its body. Based on the Cephalization index, the brightest animals on the planet are humans, [blank] by great apes, porpoises, and elephants. As a general [blank] , animals that hunt for a living (like canines) are smarter than strict vegetarians (you don't need much intelligence to outsmart a leaf of lettuce). Animals that live in social groups are always smarter and have larger EQs than solitary animals.