天山7-Q35:

Until recently, zoologists believed that

all species of phocids (true seals), a pinniped

family, use a different maternal

Line strategy than do otariids (fur seals and

(5) sea lions), another pinniped family. Mother

otariids use a foraging strategy. They

acquire moderate energy stores in the

form of blubber before arriving at breeding

sites and then fast for 5 to 11 days after

(10) birth. Throughout the rest of the lactation

(milk production) period, which lasts from

4 months to 3 years depending on the

species, mother otariids alternately forage

at sea, where they replenish their fat

(15) stores, and nurse their young at breeding

sites. Zoologists had assumed that

females of all phocid species, by contrast,

use a fasting strategy in which mother

phocids, having accumulated large energy

(20) stores before they arrive at breeding sites,

fast throughout the entire lactation period,

which lasts from 4 to 50 days depending on

the species. However, recent studies on

harbor seals, a phocid species, found that

(25) lactating females commenced foraging

approximately 6 days after giving birth and

on average made 7 foraging trips during

29

the remainder of their 24-day lactation

period.

(30) The maternal strategy evolved by

harbor seals may have to do with their

small size and the large proportion of their

fat stores depleted in lactation. Harbor

seals are small compared with other phocid

(35) species such as grey seals, northern elephant

seals, and hooded seals, all of which

are known to fast for the entire lactation

period. Studies show that mother seals of

these species use respectively 84 percent,

(40) 58 percent, and 33 percent of their fat

stores during lactation. By comparison,

harbor seals use 80 percent of their fat

stores in just the first 19 days of lactation,

even though they occasionally feed during

(45) this period. Since such a large proportion

of their fat stores is exhausted despite

feeding, mother harbor seals clearly cannot

support all of lactation using only energy

stored before giving birth. Though smaller

(50) than many other phocids, harbor seals are

similar in size to most otariids. In addition,

there is already some evidence suggesting

that the ringed seal, a phocid species that

is similar in size to the harbor seal, may

also use a maternal foraging strategy.

天山7-Q35:

According to the passage, until recently zoologists believed which of the following about

all phocid mothers?

A. Their fasting periods after giving birth were typically shorter than those of otariids.

B. Their lactation periods were generally as long as those of comparably sized

otariids.

C. They acquired only moderate energy stores in the form of blubber before arriving

at breeding sites.

D. They depleted less than a third of their stored body fat during lactation.

E. The replenished their fat stores only after their lactation period ended.

答案是E，我觉答案应该是A，因为A至少还提到“Zoologists had assumed that

females of all phocid species, by contrast, use a fasting strategy in which mother phocids“

而E中的only太绝对了吧！