[ti:Scientists Argue over Intelligence of T. Rex]
[by:www.21voa.com]
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[00:00.04]A group of scientists has disputed
[00:02.52]a study published last year
[00:04.76]that estimated the intelligence
[00:07.00]of the dinosaur Tyrannosaurus rex
[00:09.60]to be similar to a baboon's.
[00:12.36]The group disputed last year's report
[00:15.28]from Suzana Herculano-Houzel
[00:18.12]at Vanderbilt University in Tennessee.
[00:20.92]It said the study did not use studies of reptiles
[00:25.12]like crocodiles and alligators
[00:27.80]to explain dinosaur brains.
[00:30.20]Zoologist Kai Caspar
[00:33.12]is with the Heinrich Heine University in Germany.
[00:36.76]Caspar was the lead author of the new study
[00:40.92]published in The Anatomical Record.
[00:43.92]Speaking of dinosaurs like T. rex,
[00:47.28]he said "their neuron numbers
[00:50.16]were likely not exceptional,
[00:52.24]especially for animals of their body mass."
[00:55.32]But Herculano-Houzel stands by her research.
[00:59.80]She said her work studied the "brain
[01:02.12]to body-size relationship"
[01:04.80]of modern-day theropod relatives
[01:07.60]such as ostriches and chickens.
[01:10.80]The brain size and number of neurons
[01:14.56]of those animals, she said, support her theory.
[01:18.52]A theropod is a group of dinosaurs
[01:21.52]that includes T. rex.
[01:23.72]She said only one issue is being disputed:
[01:27.92]"What was actually the size of dinosaur brains.
[01:31.68]Even then, we're talking about the difference
[01:34.72]between a T. rex brain
[01:37.20]being baboon or monkey sized."
[01:39.68]Caspar said his research group
[01:42.56]also considered modern birds.
[01:46.56]"Reptiles are certainly not as dim-witted
[01:49.04]as is commonly believed," he said.
[01:51.76]Speaking of T. rex, he noted:
[01:54.28]"it was certainly a behaviorally sophisticated animal."
[01:59.32]Caspar said he had additional concerns
[02:02.56]about Herculano-Houzel's research.
[02:05.60]One issue, he said, is that while humans, baboons,
[02:10.12]other mammals and even birds
[02:12.88]have brains that fill the space protected by the skull,
[02:16.72]"this is not the case for reptile species."
[02:20.20]He noted the brain of reptiles fills
[02:24.24]only about 30 to 50 percent of the space.
[02:28.32]He also said it is not known how many neurons,
[02:31.88]or brain cells, were present in dinosaur brains.
[02:36.44]"Looking at living animals, we see that
[02:39.08]neuron counts are actually not a good indicator
[02:42.08]of intelligence in the first place," Caspar added.
[02:45.92]Caspar noted the study from 2023
[02:49.52]assumed the brain filled the whole skull,
[02:52.80]which, he said, "was certainly not the case."
[02:56.52]Scientists have been learning about dinosaurs
[02:58.96]for about 200 years.
[03:01.04]But much remains to be discovered.
[03:04.36]Thomas Holtz is the co-author of the new study.
[03:08.24]He studies dinosaurs at the University of Maryland.
[03:11.80]He said estimating the intelligence of animals
[03:15.40]that lived over 60 million years ago is difficult.
[03:20.04]"It would be nice if we could just estimate one number
[03:23.72]and unravel the whole complexity
[03:27.00]of an animal's biology and lifestyle,
[03:29.40]but nature isn't like that," Holtz said.
[03:33.32]He said T. rex probably had an intelligence level
[03:37.00]somewhere between that of birds and reptiles.
[03:41.36]"Many of our common assumptions
[03:43.16]don't really hold up when you...examine
[03:45.64]what real animals do in the real world," he said.
[03:49.12]I'm Dan Friedell. 更多听力请访问21VOA.COM