ST_004

?

綜合寫作

Lions are the only species of large cats that live in groups. Female lions especially tend to band together, forming prides (extended family groups) with their daughters, sisters, and cousins. This unique evolutionary trait must yield important benefits to the survival of the species. Researchers have identified several possible reasons why lions have evolved to live in groups, when most other cats, such as leopards, tigers, and cheetahs, do not.

First, some researchers suggest that female lions have evolved to live in groups because they benefit from feeding their young cooperatively. Within a pride, female lions that give birth around the same time form a nursery group and are almost inseparable for the next one to two years. Long-term observation of lions in the wild confirms that young cubs can nurse (drink milk) from any female in the nursery group, not just their own mother.

Second, lions employ hunting tactics that require group cooperation. Research shows that lions perform highly differentiated roles in group hunts. For example, some lions almost always join a hunt only in its final stages, after other lions have begun chasing the prey. Cooperative hunting seems to be precisely coordinated to maximize the chances of catching challenging prey. Living in groups,therefore, may help lions to obtain food more efficiently.

Finally, some zoologists have proposed that female lions form social groups to defend their cubs from danger. Adult male lions are the biggest threat to cubs. Sometimes a male lion takes over a female group, and when this happens the male attempts to kill all cubs in the group so that the mothers will be ready to mate and reproduce again. Male lions are larger than females, and it takes several females to chase away a male. If males were able to kill cubs frequently, there might not be enough cubs reaching adulthood, so females form groups to repel takeover attempts by males.

聽力文稿

見評論區(qū)。