Squirrel foraging paper(2)

Squirrel foraging paper(2) - Predation Threat and Food...

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Predation Threat and Food Density Trade-Off Found in Food Foraging of Sciurius Carolinensis Molly Shepherd Introduction Throughout the natural world, there are instances where animals have to make a decision. These decisions could include where and when to eat, when to mate and who to mate with, or whether to sleep or stay alert to watch for predators. In some cases, these decisions are an all or nothing affair. What I mean to say is that an animal is only able to accomplish one of the said actions or concerns while having to disregard the other. For example, a hungry bear is unable to hunt while sleeping. This is where the decisions come into play in animal behavior. In many cases the decisions (because of their all or nothing circumstance) is a trade-off between the actions or circumstances (Dill 1986). This was the thought that was questioned in this study. Placed in a circumstance where an animal must choose between actions (taking into account the benefits that could be gained or lost) what choice will the animal prefer? These questions are important to understand on many levels, however the key idea is that if we can understand these behaviors and how variables influence them, a pattern will emerge and we can begin to make predictions of other similar cases. (Skelly 1993) In a study preformed by Ghalambor and Martin, the question of predication risk to offspring and adults of southern and northern hemisphere birds were researched. Typically in southern hemisphere birds the adults have a higher survival rate and lower clutch number of offspring in comparison to northern hemisphere birds. In the study, they manipulated the predication risk of adults vs. offspring to see whether the birds would choose to protect themselves or their offspring. They discovered that the northern hemisphere birds reduced the risk to their offspring even to a risk to themselves. In the
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same conditions the southern hemisphere birds responded to a higher predication risk to themselves even at the cost of their offspring. In the case of this trade-off, the birds had to decide whether the wellbeing of themselves or their offspring was more important. If they sacrificed themselves, they would not be able to live and produce new clutches of offspring, however their offspring would be able. (Ghalambor 2001) The following study highlights the tradeoff of the threat of predators and food density in the decision-making in foraging of the grey squirrel ( Sciurius carolinensis ). This is done in one of the most fundamental tradeoffs in animal behavior; the threat of predation and foraging. Threat of predators is manipulated by the distance the food is located from a covered area. The closer the squirrel is to cover the less of a threat it has from the predators and vies versa. The topic of interest that was examined in this
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Squirrel foraging paper(2) - Predation Threat and Food...

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