ACT Reading Practice Test 102: NATURAL SCIENCE

DIRECTIONS: Each passage is followed by several questions. After reading a passage, choose the best answer to each question and fill in the corresponding oval on your answer document. You may refer to the passages as often as necessary.


NATURAL SCIENCE: This passage is adapted from the article "Call of the Leviathan" by Eric Wagner (©2011 by Smithsonian Institution).

In 1839, in the first scientific treatise on the sperm
whale, Thomas Beale, a surgeon aboard a whaler, wrote
that it was "one of the most noiseless of marine ani?
mals." While they do not sing elaborate songs, like
5humpbacks or belugas, in fact they are not silent.
Whalers in the 1800s spoke of hearing loud knocking,
almost like hammering on a ship's hull, whenever
sperm whales were present. Only in 1957 did two scien?
tists from the Woods Hole Oceanographic Institution
10confirm the sailors' observations. Aboard a research
vessel, the Atlantis, they approached five sperm whales,
shut off the ship's motors and listened with an under?
water receiver. At first, they assumed the "muffled,
smashing noise" they heard came from somewhere on
15the ship. Then they determined the sounds were coming
from the whales.

Biologists now believe that the sperm whale's
massive head functions like a powerful telegraph
machine, emitting pulses of sound in distinct patterns.
20At the front of the head are the spermaceti organ, a
cavity that contains the bulk of the whale's spennaceti,
and a mass of oil-saturated fatty tissue. Two long nasal
passages branch away from the bony nares of the skull,
twining around the spermaceti organ and the fatty
25tissue. The left nasal passage runs directly to the blow?
hole at the top of the whale's head. But the other twists
and turns, flattens and broadens, forming a number of
air-filled sacs capable of reflecting sound. Near the
front of the head sit a pair of clappers called "monkey
30lips.

Sound generation is a complex process. To make
its clicking sounds, a whale forces air through the right
nasal passage to the monkey lips, which clap shut. The
resulting click! bounces off one air-filled sac and trav-
35els back through the spermaceti organ to another sac
nestled against the skull. From there, the click is sent
forward, through the fatty tissue, and amplified out into
the watery world. Sperm whales may be able to manip?
ulate the shape of both the spermaceti organ and the
40fatty tissue, possibly allowing them to aim their clicks.

Biologist Dr. Hal Whitehead has identified four
patterns of clicks. The most common clicks are used for
long-range sonar. So-called "creaks" sound like a
squeaky door and are used at close range when prey
45capture is imminent. "Slow clicks" are made only by
large males, but no one knows precisely what they
signify. ("Probably something to do with mating,"
Whitehead guesses.) Finally, "codas" are distinct pat?
terns of clicks most often heard when whales are
50socializing.

Codas are of particular interest. Whitehead has
found that different groups of sperm whales, called
vocal clans, consistently use different sets; the reper
toire of codas the clan uses is its dialect. Vocal clans
55can be huge-thousands of individuals spread out over
thousands of miles of ocean. Clan members are not nec?
essarily related. Rather, many smaller, durable matrilin-
eal units make up clans, and different clans have their
own specific ways of behaving.

60A recent study in Animal Behaviour took the spe-
cialization of codas a step further. Not only do clans
use different codas, the authors argued, but the codas
differ slightly among individuals. They could be, in
effect, unique identifiers: names.

65Whitehead cautions that a full understanding of
codas is still a long way off. Even so, he believes the
differences represent cultural valiants among the clans.
"Think of culture as information that is transmitted
socially between groups," he says. "You can make pre
70dictions about where it will arise: in complex societies,
richly modulated, among individuals that form self-
contained communities." That sounds to him a lot like
sperm whale society.

But most of a sperm whale's clicking, if not most
75of its life, is devoted to one thing: finding food. And in
the Sea of Cortez, the focus of its attention is Dosidicus
gigas, the jumbo squid.

The most celebrated natural antagonism between
sperm whales and squid almost certainly involves the
80jumbo squid's larger cousin, the giant squid, a species
that grows to 65 feet long. The relationship between
sperm whales and squid is pretty dramatic. A single
sperm whale can eat more than one ton of squid per
day. They do eat giant squid on occasion, but most of
85what whales pursue is relatively small and over-
matched. With their clicks, sperm whales can detect a
squid less than a foot long more than a mile away, and
schools of squid from even farther away. But the way
that sperm whales find squid was until recently a
90puzzle.

1. The main purpose of the passage is to:

A. describe how sperm whales use clicks to hunt their prey.
B. evaluate historical theories regarding stern whale clicks.
C. provide details about the antagonism between sperm whales and squid.
D. explain how sperm whales generate and use clicks

2. In the eighth paragraph (lines 74-77), the passage begins to focus on the relationship between:

F. squid and their prey.
G. sperm whales and sonar.
H. sperm whales and codas.
J. squid and sperm whales

3. The main purpose of the second paragraph (lines17-30) is to:

A. compare sperm whales to telegraph machines.
B. explain the function of the spermaceti organ.
C. outline how scientists came to understand the anatomy of the sperm whale.
D. describe the sperm whale anatomy involved in cre-ating sound.

4. It can reasonably be inferred from the passage that codas are of particular interest because scientists don't yet fully understand:

F. how codas help sperm whales hunt.
G. how codas function in sperm whale socialization.
H. why codas are emitted only by male whales.
J. why codas are so difficult to detect.

5. As it is presented in the passage, the study that appeared in Animal Behaviour concluded that sperm whale vocal clans:

A. each use a distinct dialect, and individuals within each clan have unique codas.
B. can adopt the codas of other clans, but individuals within each clan maintain unique dialects.
C. each use many dialects, and individuals within each clan develop complex codas.
D. can adopt the codas of other clans, but individuals within each clan retain unique identifiers.

6. The passage indicates that compared to the sounds beluga whales and humpback whales make, the sounds sperm whales make are:

F. more complex and varied.
G. more frequent and melodic.
H. less elaborate and songlike.
J. less enigmatic and repetitive

7. According to the passage, who confirmed the observa-tion that sperm whales make loud knocking noises?

A. Beale
B. Nineteenth-century whalers
C. Woods Hole scientists
D. Whitehead

8. As it is used in line 25, the word runs most nearly means:

F. acts.
G. hastens.
H. operates
J. leads

9. Based on the passage, the notion that slow clicks are related to sperm whale mating behavior is best described as a:

A. fact that is supported by several scientific studies.
B. fact that whalers discovered in the 1800s.
C. reasoned judgment from an expert in biology.
D. reasoned judgment from the passage author.

10. Which of the following statements about the mystery of how sperm whales locate squid is best supported by the passage?

F. The mystery was solved in the 1800s.
G. The mystery was solved recently.
H. The mystery is likely to be solved in the near future.
J. The mystery is likely to remain unsolved until better technology is invented.