Brain |
The brain size of a bottle-nosed dolphin is comparable to ours at birth, dolphins have large brains for their bodies and, during their lifetime develops well into the upper levels of the maximum size for modern man -- about 1700 grams. A dolphin's brain size increases very rapidly during youth and seems to slow down at nine years of age. This decrease is less than our slow down, which occurs at our equivalent age of 17 years and afterwards. As a brain grows in size and as a child ages, immersed in many daily language situations, both brain and language increase in complexity. The usual human brain reaches 1400 grams at 10 to 17 years of age. The levels of complex thinking at this time increase tremendously over that of beginning speech. |
Absolute Weight of Brain: Man & Tursiops truncatus Brain Weight(grams)| Age of Man| Age of Dolphin| Length of Dolphin 1200 41 months 23 months 6' 6" 1350 78 months 28 months 7' 8" 1450 17 years 8 years 7' 10" 1600 10 years 8' 6" 1700 ? ? |
This chart shows how brain weight between man and dolphin compares during normal growth. If brain weight versus body weight is an accurate indicator of intelligence, then the above chart would indicate that a dolphin continues to increase its intelligence as it ages. From another source I found this; it compares a dolphin's brain weight with other animals. |
Average Brain Ratios Species| Brain Weight| Body Weight |Ratios Human 3.1 lbs 150 lbs 2.1 % Dolphin 3.5 lbs 300 lbs 1.19% Chimp .75 lbs 110 lbs .70% |
This information shows that, if brain weight is a true measure of intelligence, Man is superior, followed by dolphins with the chimp trailing third. Researchers have also pointed to the parallels in the organization of dolphin and primate brains as more evidence of high intelligence in dolphins. The last table I would like to include in this paper more or less concludes the information drawn from the first two tables: |
Largest Known Adult Brain Reference| Weight in Grams| Body Length| Species| Common Name Vierordt H. (1890) 1450 (av: 1250) 5'9" Homosapiens Man Lilly (1958) 1700 8'6" Tursiopstruncatus Bottle-noseDolphin Tower (1954) 6075 ? Proboscidae Elephant Jansen (1952) 7200 54' Balaenopteraphipalus Fin whale Kojima (1951) 9200 49' Physetercatadon Sperm Whale |
Comparing dolphin's brains to ours and others we can claim that it is deductible that dolphins could be intelligent enough to communicate. Some have gone so far as to suggest that dolphins actually have a language that humans simply cannot comprehend. But others say that in our enthusiasm to anthropomorphize dolphins, we give them powers they just don't possess. A closer look suggests that much of the dolphin's large brain is taken up with echolocation and handling acoustical information -- processes at which they excel. But dolphins tend to rank at about the level of elephants in "intelligence" tests and haven't shown any unusual talent at problem solving. v An experiment, done by Dr. Lilly while stimulating parts of Dolphin #6's brain with electrical currents, proved that dolphins are capable of making more sounds than we had been previously aware of. Apparently Dr. Lilly's probe stimulated the part of the brain controlling the vocal cords. I couldn't find the exact number of sounds the dolphin produced, as it had been taped. However Dr. Lilly made the comment that he heard more types and variations of whistles, buzzing, rasping barks, and Bronx cheer-like noises than he'd ever thought a dolphin capable of. v Another dolphin was taped, after Dr. Lilly said "the TRR is now ten per second" (train repetition rate) repeating "TRR" in a high pitched, Donald Duck, quacking-like voice. The same dolphin also picked out "three hundred and twenty three" and also mimicked every laugh laughed in the lab at that time. v A dolphin kept in complete captivity (with only human contacts) was trained to rise to the surface, emit a sound when any word was shouted over the surface of the water. After a careful examination of all the tapes, a conclusion was made that 18% of the sounds he emitted were considered humanoid emissions -- in other words, the dolphin was imitating our words v Dolphin researcher Pieter Arend Folkens tells this story: "Since trash can be dangerous to dolphins if ingested, some of the animals at Marine World Africa USA were trained to retrieve the trash and return it to the trainer for a reinforcement reward. |