An Analysis of Squirrel Behavior in Ecology

Abstract

As our population expands and cities grow and spread out into the country, the line between wilderness and civilization becomes thinner and thinner. The relationship between animals and humans becomes more and more strained, and the understanding of animal behavior in the presence of man becomes increasingly important. A great example of a species that has successfully adapted to life with humans is the gray squirrel. My study tried to prove that squirrels learn to live with humans and become comfortable functioning in their presence. It attempted to show that squirrels living in areas of high human traffic are braver in approaching humans than those that live in areas of low human traffic. My hypothesis was that the gray squirrels that come in contact with humans more frequently have adapted to life with people and would more readily approach me than those that have not become accustomed to human interaction. To test this hypothesis, I tested a squirrel s willingness to approach me at a location of high, medium, and low human traffic. I measured their approach in three levels: ten feet or less, thirty feet or less, and no interest. I then performed a Chi squared test to see if the locations were different from the expected results. The high traffic area and the low traffic area were significantly different. Squirrels in the high traffic area were far more willing to approach a human than those in areas of low traffic. This data supported my hypothesis that the squirrels living in areas of high human traffic would be more willing to approach me than squirrels living in areas of low human traffic. More importantly this study also shows the squirrels ability to become accustomed to interaction with humans and adapt to that environment.

Introduction

As our population expands and cities grow and spread out into the country, the line between wilderness and civilization becomes thinner and thinner. The relationship between animals and humans becomes more and more strained, and the understanding of animal behavior in the presence of man becomes increasingly important. For many species, contact with humans is ultimately detrimental if not deadly. Still, some species are successful in adapting to life in urban and even inner city settings, and many even thrive. The instances in which man comes in contact with animals is are becoming common and the manner in which we deal with these situations is a delicate subject. Can man and beast live side by side? This can best be answered by studying animals that have learned to live within the realm of human infrastructure. They are the examples of how this relationship can work. For this to be a tolerable situation, the animal must be able to interact with people without the instance being harmful to either. The evaluation of the environments of a species with established social organization within that environment could help to explain the adaptive nature of all species (Smith 1968). A great example of a species that has successfully adapted to life with humans is the gray squirrel. It has become an accepted part of almost any community that people reside in, and can be found almost anywhere in the United States. There are many factors that help to account for the squirrels successful adaptation to suburban and urban life.
The gray squirrel has been successful in adapting to civilization for many reasons. One is that when it comes to eating habits they are generalists (Follmer 1972). They can eat a variety of foods where as a specialist who eats a certain food, and only that food, would have more trouble adapting. They also have very little needs for survival and reproduction. A tree is basically all they need. Another trait that makes their assimilation easier is their ability to get used to humans. They are hardy animals and very successful reproducers (Horwich 1977) Along with these reasons, I chose the gray squirrel for my study because they are generally cooperative and observable in scientific experiments (Hazard 1974).

My study will try and prove that squirrels learn to live with humans and become comfortable functioning in their presence. It will attempt to show that squirrels living in areas of high human traffic are braver in approaching humans than those that live in areas of low human traffic. I hypothesize that the gray squirrels that come in contact with humans more frequently have adapted to life with people and will more readily approach me than those which have not become accustomed to human interaction.

Methods and Materials

To test my hypothesis I needed to set up my experiment in three locations. The first was an area of high traffic, the center of campus at Bowling Green University. The squirrels in this area are exposed to heavy human contact every day. It is also safe to assume that a lot of the squirrels in this area were raised here and have never known any other situation. These squirrels represented my group most exposed to human contact and those I thought most likely to approach me. The second location I chose was my medium traffic area. I chose a village park in the town of Luckey, Ohio. This is a small town about fifteen miles outside of Bowling Green. This park is not heavily used, but the squirrels are around humans occasionally. It is also safe to say that some of these squirrels have grown up in the presence of humans, although some may have traveled there from the surrounding forests. The third area was my low traffic area. I chose a forest just outside of Luckey. The squirrels in this forest are almost never exposed to human contact and finding them in the trees was difficult. These squirrels were raised in the absence of humans and have an instinctive fear of them.

After choosing a location, I had to find a way to uniformly draw the squirrels in to see how close they would approach me. To draw them in, I decided to use popcorn. I also had to set up a way to measure their reaction to my baiting. I decided to measure their approach in three levels, within ten feet of me (high interest, very brave), within thirty feet of me (some interest, somewhat brave), and thirty feet or more from me (no interest, not brave). I set up cones at these intervals between the squirrels and myself. I went to each location and found a squirrel. I then went more than thirty feet away from the specimen and set up cones at each interval, placing some popcorn within each level. I then sat down within the ten-foot marker and laid some popcorn around me on the ground. I then repeated this test with six different individuals at each location and measured their response accordingly. I then looked at the raw data, and compared it to the expected results I had set up previously. The expected results were two squirrels showing high braver, two being somewhat brave, and two showing no interest and no bravery. I did a Chi squared test on each location compared to the expected results to get a p value. This p value told me if there was a significant difference between those results and the expected. I could then compare that significance between those different locations as they relate to the expected results. This would tell me if squirrels with more human contact were braver in approaching me than those with little or no human contact.

Results

The results of my study (see appendix I) were very different in each area. The p values for the high traffic area and the low traffic area showed that they were significantly different than the expected results, while the medium traffic area was not significantly different. The p value for the high traffic area was 0.03, the low area was 0.03 as well, and the medium area was 0.61. In a comparison of the three, the high traffic area was significantly from the expected results because five of the six squirrels came within ten feet of me. The low traffic area was different because none of the six squirrels came within ten feet and five of them showed no interest at all. In the medium traffic area the squirrels were distributed similar to the expected with two coming within ten feet, three within thirty and one showing no interest. 

Discussion

This data supported my hypothesis that the squirrels living in areas of high human traffic would be more willing to approach me than squirrels living in areas of low human traffic. The high traffic area was significantly different from the expected results. Five of the squirrels came within ten feet of me. This shows that the squirrels are accustomed to contact with humans and are fairly fearless. This could be a learned behavior or it could be inherent in the species if many generations have lived with humans. The medium traffic area was not different than the expected results, but this also supports my hypothesis in that in areas of occasional contact, some squirrels were brave and some were wary of people. Even those squirrels that did approach me were not as comfortable as those that approached me in the high traffic area. In the low traffic area, the majority of squirrels did not show any interest. These squirrels rarely see humans and are instinctively hesitant to trust people. This further supports my hypothesis showing that squirrels are less brave when they haven t been exposed to humans. More importantly this study also shows the squirrels ability to become accustomed to interaction with humans and adapt to that environment. Further studies of this kind with squirrels and other species are important because they can help us understand the relationships between humans and wildlife in populated areas. A better understanding of these relationships will help ease the tension in these situations and allow us to help species transition into life amongst us.

References

  1. Follmer, David (1972) Food Preferences of Squirrels. Ecology: 81-82
  2. The Ecological Society of America
  3. Hazard, Evan (1974) Activity Among Squirrels. Thesis: University of Michigan
  4. Horwich, Robert (1977) The Ontogeny of Social Behavior in Gray Squirrels.
  5. Thesis: University of Maryland
  6. Smith, Christopher (1968) The Adaptive Nature of Social Organization in the
  7. Genus of Three Squirrels. Ecological Monographs