第三篇阅读貌似是说snowshoe hare的，真他NND长啊这篇。。。说科学家刚研究snowshoe fare 的forage行为的影响因素，researchers发现某处fare被捕食的几率在近几年大大减少，其原因是因为fare本身的density变少，而捕食者的数量则基本没变(我觉得我这里要不是记错了就是理解错了。。大家见谅，反正大概就是这个意思，到时候考场的时候注意看一下就OK)先假设其行为是因其对捕食者的预期而改变，而fare对于捕食者风险的判断标准不同分为两种情况，第一种是在fare被追逐的时候fare认为他们被捕食，另一种是在 fare发现捕食者踪迹的时候就断定他们有被捕食的危险，于是这两种不同标准的判断导致了其forage行为被影响的程度。。然后捕食者又在一处地方设立了栅栏，在建立栅栏的区域内没有捕食动物，并且观察在栅栏内的fare和栅栏外的fare的forage的行为并没有差别，于是researcher假设 fare的影响forage的因素并不是被捕食的预期而可能是preference。 PS这篇的考点很细，感觉蛮恶心的，大家考试的时候仔细点。。

　　题目有：问在大部分实验中，s,l,c的数量有什么变化。我选的他们的数量维持constant(因为研究者最后说s收到的威胁没变)。还有问以下那个说法正确，我选的s在很多情况下可以从l,c手中逃走。最后一题问的哪个最能削弱最后一段的结论，我选的s藏在篱笆下的地方有很多小洞，他们可以快速从那里逃走但l,c却过不了那个洞。

　　snowshoe hare foraging behavior的那个题，的确巨长，一屏半，机经的结构还是差不多的，其中第二段没有题，可以看得快一点，第三段比较重要，说的是兔子被用篱笆关起来以后，这样可以避免天敌的存在，但是发现兔子的捕食行为没有改变，由此得出结论说兔子的捕食行为跟天敌没有关系，主要是跟食物的可得性有关。

　　有一个题定位在第一段和第二段初，问的是最近一段时间兔子和天敌数量的变化，原文说天敌的数量基本没变，但是兔子和天敌的比例上升了，那就选天敌没变儿兔子上升的那个选项

　　有一个题问科学家用篱笆的那个实验，如果下面哪个成立的话可以削弱之，选的是虽然拿篱笆隔开了，但是兔子可以跑的出去还是天敌能跑的进来还是什么的，不记得了，反正就是隔不住的意思

　　有一个题问下面描述兔子的行为哪一个靠谱，好像是选兔子不会反复地去同一个觅食点觅食，不确定，但是其他的迷惑选项有兔子的觅食会被天敌的出没影响，这个是不对的

　　月讀JJ46動物覓食 原文求確認~

　　JJ46 動物覓食求確認~~感謝!

　　I examined the effects of predation risk on the behaviour and population dynamics of snowshoe hares (Lepus americanus) during a cyclic peak and decline (1989-1993) near Kluane Lake, Yukon. Like most heavily preyed upon animals, snowshoe hares have to balance conflicting demands of obtaining food at a high rate and avoiding predators. The consequences of adopting predator avoidance behaviours under high risk of predation in winter may influence population dynamics of hares.

　　Changes in patterns of winter habitat use, survival, body mass, and female reproduction were compared on four experimental areas: (i) where predation risk was reduced by excluding-out terrestrial predators (FENCE), (ii) where food supply was supplemented with ad lib rabbit chow (FOOD), (iii) a combination of these two treatments (FENCE+FOOD), and (iv) an unmanipulated CONTROL. Three hypotheses were compared. The food hypothesis predicts that hares use habitats with the highest amounts of food: body mass remains high, but survival is reduced. The predator avoidance hypothesis predicts that hares use habitats with the lowest risk: survival is high, but body mass decreases. The predation-sensitive foraging (PSF) hypothesis predicts that both survival and body mass decline because a trade-off exists between predation risk and food availability. At peak densities hares used open habitats where food was readily available. However, as predation risk increased during the population decline, hares increased their use of safer, closed habitat and shifted their diet to include a greater proportion of poorer quality spruce twigs. This change in behaviour resulted in lower female body mass and reduced fecundity on the CONTROL area, even though sufficient winter forage was available. A similar decrease in body mass was observed on the FOOD treatment during the third year of the population decline. On FENCE+FOOD, female body mass and fecundity remained high during the decline. Similarly, body mass did not decline on the FENCE treatment. These results supported the PSF hypothesis where terrestrial predators were present (CONTROL and FOOD), and the food hypothesis where terrestrial predators were absent (FENCE and FENCE+FOOD). Hares appear to have a limited ability to reduce exposure to predators because they have no absolutely safe refuge from predators, and they have limited reserves of energy during winter. Preliminary evidence suggests that physiological stress associated with high risk and poor condition is elevated during the population decline. I suggest that deleterious maternal effects mediated by predation risk may introduce a lag of one generation into the 10- year population cycle of snowshoe hares.

　　2. Forage and predators的那个，没看见有原文，不过jj上已经说的比较详细了

　　1) 问文章主旨，真的不记得选什么了，但是每个选项都特别长就是了，耐着性子好好看其实还比较容易排除的

　　2) 问哪个反驳了researchers的实验，就是说那些predators能在fence两边过来过去

　　3) 还问了一个这个东西什么snowxxx hares的这个东西，它会做一下哪一项。基本是定位在第二段吧。。。要不然就是第三段，但是确实有点变态，我选了一个说这种生物在perceived risk of predators很low的时候会去不同的地方吃东西达到他们吃食物的标准量。因为文中有一个地方说他们在觉得risks很高的时候不会做什么什么(忘记了。。。)减少自己吃食物的量，大概就是取非了。但是要仔细看，有些选项挺迷惑人的。

　　4) 还问了第一段的作用。。。(不知道为什么我总是碰见问我第一段干嘛的题。。。)，这个也真心不记得了。。。总之这篇的选项的特点都是十分长。。。大家一定要耐心看

　　以上就是动物觅食行为研究的GMAT阅读机经的全部内容，考生可以有选择的看看，机经虽好，但是也要适度哟。