托福閱讀材料之Food Caching

　　Humans may be one of the smartest animals on the planet, but when it comes to remembering where things are, Clark’s nutcrackers have us beat.

　　A relative of jays and crows, nutcrackers hide pine seeds in the ground each autumn so they have a source of food during the Colorado Rocky Mountain winter. They cache as many as 30,000 seeds in 5,000 different locations over a fifteen square mile area. Since they cannot smell the seeds buried in the soil very well, they must use their remarkable spatial memory to find them.

　　Nutcrackers are not the only animals that cache food. Caching behavior is seen in birds, mammals and even insects. Chickadees store collections of seeds, insects and spiders in the bark of trees or under leaves. Red squirrels cut conifer cones from trees and bury them in plant litter on the forest floor. Harvester ants bring seeds back to their nests and store them in chambers, while honey bees save nectar and pollen in their hive.

　　Because nutcrackers are one of the best at remembering cache locations, researchers are studying them to find out why they have such great memories. Scientists know that the nutcracker’s abilities evolved because of environmental pressure. Nutcrackers with poor memories did not likely survive the harsh mountain winters. Now researchers want to find out how the brains of nutcrackers are different from other brains. They are particularly interested in the hippocampus, a small area of the brain that helps form memories. Finding out how the nutcracker’s brain is different from other species may give us clues to why humans have memory problems. It may even lead to a cure for Alzheimer’s disease.

　　人類也許是世界上最聰明的動物之一，但說到記憶，克拉克(新澤西州)的星鳥比我們?nèi)祟悘姸嗔恕?/p>

　　星鳥屬于松鳥和烏鴉的近親，它在秋天的時候把松子藏在地底下，這樣寒冷冬天的就有食物吃了。它們會儲存多達30000顆種子，而且是在十五平方公里內(nèi)的5000個不同位置。因為不能通過氣味辨別埋在土里種子的位置，它們就必須依靠驚人的空間記憶力來找到這些種子。

　　不止星鳥會儲存食物。哺乳動物、鳥類，甚至昆蟲都會貯藏東西。山雀貯存種子，還有樹皮和樹葉下面的昆蟲，蜘蛛。紅松鼠會將針葉樹上的果實割下來，然后埋在森林地面的落葉中。紅蟻會將種子拖到巢穴內(nèi)并貯存在室內(nèi)。蜜蜂也是把花蜜和花粉貯存在蜂房里的。

　　因為星鳥是最擅長記住儲存位置的動物之一，研究人員正仔細觀察它們，想找出星鳥擁有超強記憶力的原因。科學家明白星鳥的技能是由于環(huán)境形成的。記憶力差的星鳥在這么嚴酷的冬天也許不能生存?，F(xiàn)在，研究人員想找出星鳥的大腦有什么不同之處。他們對(腦內(nèi)的)海馬狀突起很有興趣，那是大腦里幫助記憶的很小一個區(qū)域。找出星鳥與其他物種大腦結構的區(qū)別也許會給出線索，了解為什么人類記憶會出現(xiàn)各種問題。甚至能幫助治療老年癡呆癥。