ACT
Practice Test 28

Previous Next

NATURAL SCIENCE: The Eating Habits of Related Primates

Scientists know very little about the eating habits of our ancestors who lived over two and a half million years ago. To solve this problem, scientists have started examining chimpanzees’ hunting behavior and diet to

Line 5 find clues about our own prehistoric past. It is not difficult to determine why studying chimpanzees might be beneficial. Modern humans and chimpanzees are actually very closely related. Experts believe that chimpanzees share about 98.5 percent of

10 our DNA sequence. If this is true, humans are more closely related to chimpanzees than to any other animal species. In the early 1960s, Dr. Jane Goodall began studying chimpanzees in Tanzania. Before the 1960s,

15 scientists believed that chimpanzees were strict vegetarians. It was Goodall who first reported that meat was a natural part of the chimpanzee diet. In fact, Goodall discovered that chimpanzees are actually very proficient hunters. Individual chimpanzees have been

20 known to hunt and eat more than 150 small animals each year. Among the chimpanzees’ favorite prey are the red colobus monkey, feral pig, and various small antelope species. The red colobus monkey is one of the most important animals in the chimpanzees’ diet. In one
25 notable study, the red colobus monkey accounted for more than 80 percent of the animals eaten by one group of chimpanzees. Despite these findings, scientists still maintain that chimpanzees are mostly fruit-eating creatures. In fact,

30 meat composes only about 3 percent of the chimpanzee diet. This is substantially less than the quantity of meat consumed by the average human. Studies show that chimpanzees do most of their hunting in the dry season. August and September appear to be the most popular

35 months for hunting. During the dry season, food shortages in the forest cause the chimpanzees’ body weight to drop. Consequently, chimpanzees supplement their diets with meat. During the height of the dry season, the estimated meat intake is about 65 grams of meat per day

40 for adult chimpanzees. This is comparable to the quantity of meat eaten by modern human societies whose members forage when other food sources are scarce. The chimpanzees’ eating habits also closely resemble those of the early human hunter-gatherers.

45 Humans and chimpanzees are the only members of the Great Ape family that hunt and eat meat on a regular basis. However, like chimpanzees, humans are not truly carnivorous creatures. In fact, most ancient humans ate a diet composed mostly of plants, and even

50 modern humans are considered omnivores because they eat fruits, vegetables, and meat. Most people assume that food choices are based solely on nutritional costs and benefits. Although it is clear that the hunting habits of chimpanzees are

55 guided mostly by nutritional needs, some aspects of the chimpanzees’ behavior are not well explained by nutrition alone. Researchers suggest that chimpanzees might hunt for social gain. For instance, a male chimpanzee might try to demonstrate his competence to other male

60 chimpanzees by killing prey. Chimpanzees may also use meat as a political tool to punish rivals and reward friends. However, a study also shows that female chimpanzees that receive large portions of meat after a hunt have healthier and stronger offspring. This indicates

65 that there might be reproductive benefits to eating meat as well. The information that scientists have been able to gather regarding chimpanzee hunting behavior is shedding some light on the eating habits of our ancestors.

70 Further investigation is needed, however, to provide stronger evidence regarding this aspect of man’s prehistoric past.

The main purpose of the passage is to:

  • Solution

    The best answer is B. The passage discusses first the diet and hunting behaviors of chimpanzees, and then moves on to briefly discuss similar human activity in diet and early human hunting and gathering. This is the overall focus of the passage, which most closely corresponds with answer choice B. Answer choice A may appear to be correct; however, the passage solely discusses diet and hunting habits; the passage does not go into depth about biological and physiological similarities between humans and chimpanzees.

It can be inferred from the passage that chimpanzees:

  • Solution

    The best answer is J. As stated in the passage, “chimpanzees do most of their hunting in the dry season.” The passage also notes that chimpanzees supplement their diet with meat when food shortages occur in the forest, particularly during dry season. Although answer choices G and H may appear to be correct, they are not inclusive of all of the environmental factors that play a role in the hunting habits of chimpanzees. Thus, answer choice J is correct. Answer choice F is incorrect because although the red colobus monkey is noted as “one of the most important animals in the chimpanzees’ diet,” the relative ease of hunting the red colobus monkey is not specified.

According to the passage, the word proficient (line 19) most nearly means:

  • Solution

    The best answer is A. It is noted in the passage that “chimpanzees are actually very proficient hunters,” and that “Individual chimpanzees have been known to hunt and eat more than 150 small animals each year.” Answer choice A–“skilled”–makes the most logical sense within the context of the passage. The sheer number of animals that chimpanzees can successfully hunt each year tells you that they are competent at hunting and can find plenty of prey to supplement their diet each year.

According to the passage, which of the following statements regarding the eating habits of chimpanzees is true?

  • Solution

    The best answer is H. The passage indicates that chimpanzees prey on many different kinds of small animals and that the amount of meat that they consume varies each year with environmental factors. Not only this, but chimpanzees’ diets can vary due to social and reproductive factors. This information best supports answer choice H; the exact diet of chimpanzees cannot be determined. Answer choice A is incorrect because the study in the passage was done in the wild. Answer choice G is incorrect because the passage clearly states “Although it is clear that the hunting habits of chimpanzees are guided mostly by nutritional needs … chimpanzees might hunt for social gain.” It is a possibility that chimpanzees’ eating habits could be influenced by social factors, but not a given fact.

Based on the context of the passage, the author most likely makes the comparison between chimpanzees and humans (lines 45–51) in order to suggest that:

  • Solution

    The best answer is B. The passage states that “It is not difficult to determine why studying chimpanzees might be beneficial. Modern humans and chimpanzees are actually very closely related. Experts believe that chimpanzees share about 98.5% of our DNA sequence,” which best supports answer choice B.

As it is used in the passage, the word forage (line 42) most nearly means:

  • Solution

    The best answer is H. As stated in the passage, “This is comparable to the quantity of meat eaten by modern human societies whose members forage when other food sources are scarce.” This sentence indicates that these humans looked for other sources of food, such as meat, when their normal food sources were in short supply. This corresponds with answer choice H, “search for food.”

According to the passage, Dr. Jane Goodall’s research was important because:

  • Solution

    The best answer is B. The passage states that “It was Goodall who first reported that meat was a natural part of the chimpanzee diet. In fact, Goodall discovered that chimpanzees are actually very pro- ficient hunters.” This tells us that Goodall was the first scientist to discover previously undocumented chimpanzee behavior, and that chimpanzees were actually not vegetarians. Answer choice D might appear to be correct; however, the passage refers to the colobus monkey information as being found in “one notable study,” not the study of Dr. Goodall.

It can be inferred from the passage that ancient humans and chimpanzees:

  • Solution

    The best answer is J. According to the passage, humans and chimpanzees share many biological and social qualities. The passage states “Researchers suggest that chimpanzees might hunt for social gain.” You can infer then, that ancient humans also hunted for social gain and prestige in their communities. The other answer choices are not supported by information in the passage.

According to the passage, chimpanzees hunt primarily because of:

  • Solution

    The best answer is B. As stated in the passage, “During the dry season, food shortages in the forest cause the chimpanzees’ body weight to drop. Consequently, chimpanzees supplement their diets with meat.” This best corresponds with answer choice B. Answer choices A, C, and D are not supported by details found within the passage.

In the context of the passage, the tone in lines 52–66 can best be described as:

  • Solution

    The best answer is J. The lines in the question stem refer to the sixth paragraph, which focuses on a discussion of food choices among chimpanzees. The paragraph is strictly informational, and does not express any emotion.

Attempted

0

Correct

0

Wrong

0

Complete
Mock Tests
Attempted
Wrong
Correct
Passage Questions