Moving to the present, dolphins have brains that are about "five times larger for their body size when compared to another animal of similar size," Marino said. "In humans, the measure is seven times larger-not a huge difference."
She concluded, "Essentially, the brains of primates and cetaceans arrived at the same cognitive space while evolving along quite different paths."
As a footnote to the above, it's important to remember that killer whales, also known as orcas, are actually the largest members of the dolphin family. Since this piece first ran, killer whales have been scrutinized due to a killer whale attack at SeaWorld. Trainer Dawn Brancheau died in the incident, which is still under investigation.
Lori Marino recently commented on the death, telling the Los Angeles Times: "I'm not trying to second-guess what was in this particular whale's mind. But, certainly, if we are talking about whether killer whales have the wherewithal and the cognitive capacity to intentionally strike out at someone, or to be angry, or to really know what they are doing, I would have to say the answer is yes."