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When adult humans meet a baby, many can't help speaking in a higher-pitched（更高音的）,sing-song voice. This shift, known as parentese, is not unique to humans——it has also been observed in animals like monkeys and gorillas. Now, scientists are adding one more species to that list: bottlenose dolphins.
Dolphins are intelligent animals that live and hunt in groups. They communicate in a unique way: every individual produces its own signature sound that acts much like an ID card, usually by its first birthday. But how does each come up with its distinctive whistle? For babies, it might have something to do with listening to Mum. To solve this mystery, researchers examined the sounds mother dolphins, make.
Scientists studied 34 years' worth of recordings of sounds made by 19 female bottlenose dolphins. When the mother dolphins were near their young, they continued to make their signature sound, but at a higher frequency. They also used a wider range of frequencies than they did when their babies were not nearby.
This discovery suggests that using these modifications mother dolphins assist their young in learning how to produce these calls themselves. Since dolphin babies often spend some years with their mothers before living on their own, it makes sense that this adaptation would help them learn to communicate. At the very least, the higher-pitched whistle likely gets the babies' attention. It's important for a baby to know, Oh, Mum's talking to me now,’ says marine biologist June Mann.
This kind of research could help us understand how language developed in humans.“It is absolutely essential to have basic knowledge about other species and how they communicate,”says Mann.“I would be really interested to see whether dolphins also change their sounds when interacting with babies of others, which is what happens in humans.”
1.What do the underlined words “this mystery” refer to in paragraph 2?
A.How dolphins develop their unique sounds.
B.Why dolphins live and play in groups.
C.What aspects of intelligence dolphins possess.
D.Whether dolphins can use parentese like humans.
2.How did the researchers carry out their study of dolphins?
A.By recording parent-child interaction frequency.
B.By analyzing mother dolphins' sound features.
C.By measuring the distance between parents and children.
D.By examining the speech organs of mother dolphins.
3.What is a suggested reason why dolphin mothers use parentese with their young?
A.To express worry and care.
B.To teach them hunting skills.
C.To help them learn to talk.
D.To distract their attention.
4.Which of the following can be the best title for the text?
A.Some new findings about dolphin communication
B.The value of studying dolphins' language
C.A comparison of the parentese of humans and dolphins
D.An introduction to the development of dolphin intelligence
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