June 21, 2010
Whales And Humans Have Much In Common
Scientists are now saying that marine mammals are not only smarter than previously thought, but many also share several attributes once claimed to be exclusively human.
Cetaceans, an order of more than 80 whales, dolphins and porpoises, have the ability to express self-awareness, suffering and have social cultures with high mental abilities, say marine biologists.
That belief is the center of attention at the International Whaling Commission (ICW) meeting being held Monday trhough Friday in Morocco.
A highly-contested proposal would allow Japan, Norway and Iceland to continue their whale hunting for another 10 years, ending a 24-year spell in which these countries have snubbed the IWC's ban on whaling.
"We now know from field studies that a lot of the large whales exhibit some of the most complex behavior in the animal kingdom," Lori Marino, a neurobiologist at Emory University in Atlanta, Georgia, told the AFP news agency.
Marino conducted an experiment with bottlenose dolphins ten years ago, in which she placed a small mark on their body and then allowed the mammals to look in a mirror. By the way the dolphins reacted to the image and then looked at the mark, it was clear that they showed a sense of self-identity, Marino concluded.
Georges Chapouthier, a neurobiologist and director of the Emotion Centre at Pierre and Marie Curie University in Paris, told AFP the findings show that dolphins, along with some higher primates, can experience not only pain, but also suffering.
Unlike nociception -- a basic nerve response to harmful stimuli found in all animals -- or lower-order pain, "suffering supposes a certain level of cognitive functioning," Chapouthier said.
"It is difficult to define what that level is, but there's a lot of data now to suggest some higher mammals have it, including great apes, dolphins and, most likely, whales," Chapouthier told AFP.
Pertaining to intelligence, cetaceans are second only to humans in brain size. More telling than volume, though, are cerebral areas which specialize in cognitive and emotional processing. It is thought that the likelihood of this evolution was partly driven by social interaction, according to several studies.
Some scientists suggest that this interaction can be described as culture, an idea usually reserved for humans.
"Evidence is growing that for at least some cetacean species, culture is both sophisticated and important," said Hal Whitehead, a professor at Dalhousie University in Halifax, in the Canadian province of Nova Scotia.
If culture is a learned behavior passed on through many generations and is different from one community to the next, then many marine mammals, such as humpback whales, are well-cultured indeed.
"At any time during the winter breeding season, all the males in any ocean sing more or less the same elaborate song, but this communal song evolves over months and years," Whitehead and colleagues noted in a study in the journal Biological Conservation.
Researchers have also observed killer whales learning from other orcas from a geographically separate group how to steal fish from longlines used by commercial fishing boats. Orcas form two separate groups that rarely intermingle. However, they have also shown that they can learn to divide food supplies, Whitehead reported.
Marino noted that "if we wipe out a sub-group [of whales], it is more than killing a certain number of individuals, it could actually wipe out an entire culture."
At a meeting of the American Association for the Advancement of Science (AAAS) in February, scientists concluded that new data on cognition and culture among whales should be the guideline for international wildlife policy.
To date that hasn't happened in any international forum, including the IWC, said Margi Prideaux, head of cetacean conservation at the Whale and Dolphin Conservation Society.
Prideaux said that apart from the focus put on what is the most humane way to kill whales, "ethics or the status of whales as sentient beings do not figure in talks at the IWC."
On the Net:
- International Whaling Commission
- Emory University
- Pierre and Marie Curie University
- Dalhousie University
- Biological Conservation
- American Association for the Advancement of Science
- Whale and Dolphin Conservation Society