Practice these TOEFL iBT listening tests to help you score high in the TOEFL Listening Section. Check the correct answers and audio transcripts below. This video is in the series of NEW TOEFL iBT Tests 2015.
Listen to part of a lecture in a biology class.
Professor
We’ve been discussing animal communication. Um today we’re going to talk about
dolphins. Now, dolphins make a wide range of communicative sounds and also display
something called vocal learning, which is the ability of an animal to modify its vocalizations
based on its experience with other animals.
Ah there are many types of dolphin vocalizations. We we still don’t know their precise
meanings—partly, I suppose, because we haven’t really tried that hard to figure
out their precise meanings—but we do know that dolphins use vocalizations as a way
of communicating with one another. And we’ve categorized their vocalizations into
three types: whistles, clicks, and burst pulses.
The dolphin whistles are very high frequency sounds, ah partially above the range
of human hearing. What’s fascinating is, each dolphin has a signature whistle, which
is unique to each individual dolphin. It allows them to call to and identify each other.
[seeing hand raised] Jennifer?
Female Student
Kind of like learning someone’s name? So . . . do dolphin parents choose names for
their children?
Professor
Well, again that’s something we don’t know, but we do know that no two signature
whistles sound identical. And, members of the same family, their signature whistles
have similar elements. Dolphins use them as contact calls—ah they they call to each
other while traveling and foraging. It helps keep the group together, and helps mothers
and children find each other. Think of it like . . . ah if you were traveling in the forest
with one other person who was just out of sight, you’d call out, “Are you there?”
and the other person would respond. But if there were several people in the forest,
you would have to call that person’s name to call to them.
In in addition to whistles, dolphins produce clicks, which are actually sonar or
sound waves. They use the clicks to communicate, but, more importantly, to navigate
and hunt. How? Well, the sonar clicks bounce off objects, and then the dolphins convert
the incoming signals into a three dimensional picture . . . a a mental map . . . of
what’s around them. The clicks are extremely sensitive and accurate. The sonar clicks
are also very strong. And there’s this theory that, one reason dolphins swim side by
side is to avoid interference from each others’ sonar clicks. Interference would be confusing
. . . it would prevent them from getting an accurate picture of their surroundings.
Ah and what’s interesting is, dolphins will turn off their sonar when another
dolphin passes in front.
Ah the third category of dolphin vocalizations is burst pulses. These are all this
other sounds the dolphin makes—squawks, squeals, barks, groans, and so on. Burst
pulses are used to display aggression, show dominance, and attract a mate. But whistles,
clicks, and burst pulses aren’t the only ways dolphins communicate. Um does
anyone remember any other ways?
Male Student
In the book, it said that they also slap their tails against the water? Oh, and . . . the air
that comes out when they breathe or whistle . . . the . . . ah . . . the bubble streams?
They can control how the air bubbles come out? I thought that was really interesting.
Professor
Yes . . . the bubble streams are very interesting. Dolphins can identify and locate each
other by their bubble streams, and they can imitate the bubble stream patterns of
other dolphins . . . sort of like saying hello. So as you can see, dolphins use many different
sounds and behaviors to convey messages to each other.
I’d like to tell you about when I was a graduate student . . . and . . . I spent one
summer on a boat in the Atlantic Ocean studying marine life. One morning there were
about 25 dolphins swimming with the boat. We could hear their clicks and whistles as
they called to each other. Now, we were there as impartial scientists, to do research,
but . . . how could we not notice the beauty as the bubble streams made patterns in
the water and the dolphins appeared to dance and play? It’s wonderful when you do
field work and actually experience something you’ve been studying in a classroom.
So if you ever have the opportunity . . . go for it.
Correct Answers:
1. D
2. C
3. B
4. A
5. D