During deep sleep, the participants' brains behaved in a similar manner seen in birds and dolphins.
2017年12月四级真题（第一套）阅读 Section C
During deep sleep,the participants' brains behaved in a similar manner seen in birds and dolphins.
2017年12月四级真题（第一套）阅读 Section C
She also knew from previous work conducted on birds and dolphins that these animals put half of their brains to sleep at a time so that they can rest while remaining alert enough to avoid predators.
2017年12月四级真题（第一套）阅读 Section C
One of the most interesting experiments with dolphins must be one done by Doctor Jarvis Bastian.
出自-2012年6月听力原文
Well, first of all, he kept the two dolphins together in the same tank and taught them to press levers whenever they saw a light
出自-2012年6月听力原文
If the light flashed on and off several times, the dolphins were supposed to press the left-hand lever followed by the right-hand one.
出自-2012年6月听力原文
If the light was kept steady, the dolphins were supposed to press the levers in reverse order
出自-2012年6月听力原文
In the second stage, Doctor Bastian separated the dolphins into two tanks.
出自-2012年6月听力原文
But in order to get their fish, both dolphins had to press the levers in the correct order
出自-2012年6月听力原文
Well, amazingly enough, the dolphins achieved a 100 % success rate.
出自-2012年6月听力原文
What were the dolphins supposed to do when they saw a steady light
出自-2012年6月听力原文
To test how responsive dolphins are to various signals.
出自-2012年6月听力原文
To see if dolphins can learn to communicate with each other
出自-2012年6月听力原文
To examine how long it takes dolphins to acquire a skill.
出自-2012年6月听力原文
Both dolphins were put in the same tank
出自-2012年6月听力原文
A previous study noted that dolphins always 34 consciously control their breathing.
2017年6月六级真题（第三套）阅读 Section A
But, as the human study suggests, another reason for dolphins keeping their eyes open during sleep is that they can look out for predators while asleep.
2017年6月六级真题（第三套）阅读 Section A
For example, dolphins, as well as other marine animals, shut down one hemisphere of the brain when they go to sleep.
2017年6月六级真题（第三套）阅读 Section A