Believe it or not, the Earthlings with the largest brains two million years ago were not humans. Nor were they apes or dinosaurs. The largest brains were those of dolphins. The most dramatic increase in brain-to-body ratio actually occurred 35 million years ago, according to Lori Marino who studies fossilized brains at the University of Atlanta. According to her research, something happened to make their medium-sized brains bigger.
But then as mysterious as its growth spurt, about 15 million years ago, their brains stopped growing. It was during this period of time, that it became man's turn. When the dolphin brain size plateaued, ours increased in sized from an orange to the size of a cantaloupe, allowing us to unseat the dolphins as the brainiest creatures on the planet.
Today, dolphin brain research indicates our ocean friends are still holding the Number 2 spot. The measure of intelligence in mammals is the ratio of brain size to body size, called the encephalization quotient or EQ. Our closest cousins, the chimpanzees are a mere 2.3 and between them and us are the bottlenose dolphins at 4.1, according to Pamela S. Turner, who writes about her findings in The Dolphins of Shark Bay.
In a Huffington Post report, Janet Mann --who's spent the past 25 years studying dolphins and lives in Shark Bay, Western Australia -- is considered the "Jane Goodall" of dolphin study. She cites examples of their intelligence in the way they use tools. A chimp might use a stick to dig out termite nests, but dolphins spend more time using a tool than any species, other than man. They actually protect their rostrums (the front part of their "beak") from abrasion by covering it with a sponge when foraging for fish at the pebble-strewn bottom of the bay.
Mann's work has shown how survival behaviors are learned and passed down generation after generation to the point where she is asking questions like "Is there a dolphin culture? Are the dolphins of Shark Bay culturally different from dolphins in other parts of the world?"
In other research, bottlenose dolphins were shown to be able to recognize themselves in a mirror and use it to inspect various parts of their bodies.
Dolphins are so intelligent, scientists are recommending they should be given the same status as humans. Some experts say it is now time for dolphins to be given 'non-human persons' standing. This would require they no longer be kept in captivity, mistreated, or face the horrendous practice of being hunted in places like Tajii, Japan.
Last September, it was an historic moment for animal activists around the world when India's Ministry of Environment and Forests agreed to ban the use of dolphins and other cetaceans such as whales for public entertainment and forbid they be held captive anywhere in India.
In years to come, who's to say the dolphin brain might not experience another growth spurt to surpass man's brain once again. According to the fictional author Douglas Adams, he most likely was of the same opinion. He followed up his science fiction odyssey, Hitchhiker's Guide to the Galaxy with a fourth book in the series titled, So Long, and Thanks for All the Fish. Its cryptic title is the message left behind by the dolphins [displaying their superior intelligence to man] when they read the signs in the Universe and knew it was time to depart Planet Earth just before it was demolished by aliens to make way for a hyperspace bypass. Now, that's some smart thinking!