天山-7-33-36

taoliang

天山-7-33～36

                            Until recently, zoologists believed that

all species of phocids (true seals), a pin-

nipped 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 for-

age at sea, where they replenish their fat

(15)        stores, and nurse their young at breed-

ing sites. Zoologists had assumed that

females of all phocids 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 phocids species, found that

(25)
                       lactating females commenced foraging

approximately 6 days after giving birth and

on average made 7 foraging trips during

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 phocids

(35)
                       species such as grey 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,

58 percent, and 33 percent of their fat

(40)        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

this period. Since such a large proportion

(45)        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

than many other phocids, harbor seals are

(50)        similar in size to most otariids. In addition,

there is already some evidence suggesting

that the ringed seal, a phocids species that

is similar in size to the harbor seal, may

also use a maternal foraging strategy.

 

T-4-26:T-7-35

According to the passage, until recently zoologists believed which of the following about all phocids mothers?

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

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

3. They acquired only moderate energy stores in the form of blubber before arriving at breeding sites.

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

5. The replenished their fat stores only after their lactation period ended.  答案e

 这里不明白的是明明是habor seal 属于  phocid.  而且habor seal 是需要在哺乳期进食的.而且答案中还有很肯定的only after

T-4-27-T-7-36

The author of the passage mentions ringed seals most probably in order to

1. provide an example of a phocid species that fasts throughout its entire lactation period

2. provide an example of a phocid species whose maternal strategy is typical of phocid species

3. provide an example of a phocid species that may deplete an even higher proportion of its fat stores during lactation than harbor seals do

4. support the assertion that harbor seals are smaller than many other phocids

5. support the assertion that harbor seals’ maternal strategy may be related to their small size  答案b

 otariids才是用maternal foraging strategy which is not typical strategy of phocid species