X-Message-Number: 28335
From: "Basie" <>
Subject: Scientist: Dolphins are stupid
Date: Sun, 20 Aug 2006 13:53:45 -0400

What is the ratio of glia to neurons in your brain?


Scientist: Dolphins are stupid

Dolphins are not as clever as previously thought

Dolphins may have big brains, but a South African-based scientist says 
laboratory rats and even goldfish can outwit them.

Paul Manger of Johannesburg's University of the Witwatersrand says the 
super-sized brains of dolphins are a function of being warm-blooded in a 
cold water environment and not a sign of intelligence.

"We equate our big brain with intelligence. Over the years we have looked at 
these kinds of things and said the dolphins must be intelligent," he said.

"The real flaw in this logic is that it suggests all brains are built the 
same... When you look at the structure of the dolphin brain, you see it is 
not built for complex information processing," he said.

A neuroethologist who looks at brain evolution, Manger's views are sure to 
cause a stir among a public which has long associated dolphins with 
intelligence, emotion and other human-like qualities.

They are widely regarded as one of the smartest mammals.

Too few neurons

But Manger, whose peer-reviewed research on the subject has been published 
in Biological Reviews of the Cambridge Philosophical Society, says the 
reality is different.

Brains, he says, are made of neurons and glia. The latter create the 
environment for the neurons to work properly and producing heat is one of 
glia's functions.

"Dolphins have a superabundance of glia and very few neurons... The 
dolphin's brain is not made for information processing it is designed to 
counter the thermal challenges of being a mammal in water," Manger said.

Manger said observed behaviour supports his iconoclastic take on dolphins as 

"You put an animal in a box, even a lab rat or gerbil, and the first thing 
it wants to do is climb out of it. If you don't put a lid on top of the bowl 
a goldfish it will eventually jump out to enlarge the environment it is 
living in," he said.

"But a dolphin will never do that. In the marine parks, the dividers to keep 
the dolphins apart are only a foot or two above the water between the 
different pools," he said.

Manger says the thought to jump over would simply not cross their 
unsophisticated minds.

Jump through hoops

They jump through hoops only because they have been conditioned to do so for 
a food reward - which may suggest the brain of a single-minded predator 
rather than a reasoned thinker.

"Dolphins can actually chain up to 16 stimulus response events, but this is 
indicative of good trainers and not intelligent animals. Stimulus-response 
conditioning is thought to be a low level of intelligent behaviour," Manger 

Manger also points to the tuna industry, which under consumer pressure has 
gone to great lengths to prevent dolphins from being caught and killed by 
accident in nets.

"If they were really intelligent, they would just jump over the net because 
it doesn't come out of the water," he said.


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