Sciurus Carolinensis

This topic submitted by Joey Eger & John Badalamenti ( egerjw@muohio.edu, badalajc@muohio.edu ) on 10/21/05. [Section: McCollum]

Natural Systems 1 Syllabus---Western Program---Miami University

Abstract: What nut does the Sciurus Carolinensis prefer to eat?
This is an interesting question, because there are many ways to look at it. We want to figure out what nuts in the area will squirrels prefer. We also want to know whether or not the squirrels will prefer nuts that are in their shells or not. Are they going to choose a whole black walnut in its shell, or a black walnut that has already been shelled? Is it easier for them to break open an acorn opposed to breaking open a walnut shell? With this information we can determine why they might choose an acorn over a walnut, because it saves them time and energy. In addition to this information, the data we gather from our experiment can tell us a lot about what makes squirrels choose a particular nut.

Introduction:
The purpose of this project is to find out the eating habits of squirrels related to their nut preference. Our lab will discover what the squirrels preferred nut is, and in essence, Òhow it is prepared.Ó We will explore the possibility of the squirrel enjoying a wide variety of nuts, showing that they are an adaptable species that can survive even if there is an alteration in their daily food intake. We will use the following nuts in our experiment: acorns, black walnuts, pecans, almonds, pine nuts, and hazelnuts. Five of each of these nuts will be placed on a plate. Taking a sample in strategic areas throughout campus, we will observe and record data concerning which nuts were taken, and how many nuts. We hypothesize that the squirrel will prefer the acorns that are unshelled, because that is the food that squirrels are most commonly portrayed eating. Oak trees also seem to be fairly common around OxfordÕs campus, so they would be plentiful in this region. Since squirrels have to break the shell of the acorn to get to the meat of the nut, we believe they will immediately choose the unshelled nut over the shelled nut.
The topic of squirrels appealed to us because we didnÕt know a lot about squirrel behavior. Since Oxford has an abundance of squirrels, we thought it would be interesting to do a project on the little critters. We chose their eating habits, because we wanted to find out if squirrels eat acorns because they are easy to store or if that is their favorite tasting nut. It is our plan to find out as much information as we can in determining this question. It will tell us what nuts the squirrels might think are the best tasting, and whether or not they prefer their nuts shelled or unshelled based on the resources we have. We can also make propositions on their survival in relation to deforestation. If a certain tree is cut down that is a significant food source, can they adapt to finding other means of sustenance?

Background Information:
The gray squirrel has been in North America for approximately 37 million years (Shaeler). It is because of its sense of timing that can be attributed to its survivability. Every fall, the squirrel gets an early start on preparing for the winter season by gathering and hiding food (Steele). It is called scatter hoarding; the squirrel cleans and buries the nut or seed in the ground in many different locations. The squirrel has a strong jaw and many sharp teeth that allow it to get through even the hardest shells with ease. The cleaning action leaves a scent so the squirrel will be able to find the food even through snowfall (Thompson). There are many seeds that are unneeded, because the squirrel will plant more than it will eat, and those forgotten nuts turn into trees and start the growth of forests. Squirrels are very adaptable creatures, which is the primary reason for their existence. They adapt to changes in the world like food sources. If a primary food source is expended, they will move as far as it takes until they find additional sources (Smith).
From our research on the internet, we found that black walnuts are high in both cholesterol and polyunsaturated fats (http://www.crainranch.com/nutrition.htm). Pine nuts are high in protein, but do not have as much fat as walnuts. Almonds contain dietary fiber, monounsaturated fat, high-quality protein, and are cholesterol free (http://www.yptenc.org.uk/docs/factsheets/animal_facts/grey_squirrel.html). Hazelnuts are a high-quality source of protein, fiber, and important antioxidants. They also contain the nutrient arginine, an amino acid that relaxes blood vessels. Pecans have over 19 vitamins and minerals and are 90% fat along with 4 grams of carbohydrates. Acorns are not as high in protein or fat as the other nuts, but they store easier than most of the other nuts when in their shell. They also are a good energy source since they are made up of 54% carbohydrates (http://www.vegsoc.org/info/nutsseeds.html). Walnuts have more than twice the protein and twice the fat content per gram, but they have 0 carbohydrates. Regarding acorns, squirrels prefer to burry them, because the moisture in the ground leeches out the bitter tasting acid called tannin (http://www.treenuts.org/).

Design and Method:
Data will be taken in an organized and scheduled manner. We will conclude that the nuts being taken by squirrels are the ones that they prefer to eat. The more nuts taken off the plate, the more they prefer that particular nut. Our plan of attack is carried out by placing five of each type of unshelled nut on one plate. Gloves will be used when handling the nuts and the plate, to eliminate some of the human odors. The plate will then be placed in a plot of land (ex: a quad, or field). This step will be repeated so there are a number of samples being taken. Observations will be taken and finalized every hour or so. After that first hour is up, data is to be recorded to see what nuts (if any) and how many nuts were taken. This process is to be repeated everyday, for at least 3 weeks to ensure accurate readings. These readings should be taken between 8:00 AM and 8 PM, to keep the time consistent.
The class will be included in our data collection. They will be told how to do the step by step laying out of plates and nuts, data recording, and the importance of placing them in different land plots. Given that class periods are 2 hours long, there is not enough time to take an efficient sample. We will give a plate and 30 nuts to each group so they can pick a day to take samples at whatever location in Oxford they chose. This will give us a larger range of data from different places around Miami UniversityÕs campus. A data table in the lab will show what nuts, and how many nuts were taken off of which plate, and on what order. It is important to note that readings will not be taken on days of bad weather (rain or snow), so we can keep our experiment more consistent.
The other variable we will be testing is whether the squirrels prefer acorns and black walnuts in the shell or out of the shell. This will be organized similar to the preceding method, except only the same kind of nut will be on a plate. A plate of ten acorns (five shelled, and five unshelled) will be placed on a plate. Observations and consistent monitoring every hour will determine if the squirrels are taking the shelled nuts over the unshelled nuts.

Materials:
-gloves
-plastic plates
-shelled/unshelled acorns
-shelled/unshelled black walnuts
-pecans
-almonds
-pine nuts
-hazelnuts (filberts or cobnuts)

Websites:
http://www.vegsoc.org/info/nutsseeds.html
http://www.lewis-clark.org/content/content-article.asp?ArticleID=2173
-ÒObserved a number of squirrels swiming the Ohio and universally passing from the W. to the East shore they appear to be making to the south; perhaps it may be mast or food which they are in search of.Ó
-ÒLewis continued to witness the migration every day for the rest of the week, but wrote no more about this animal. He may or may not have known, but it had already been described and named Sciurus carolinensis by Johann Friedrich Gmelin (1748-1804) in 1788.Ó
-ÒThe common name, squirrel, and the generic name Scuirus is from the Greek skuiros, meaning "shade tail." The average lifespan of an eastern gray squirrel is eight to ten years.Ó
http://wonderclub.com/Wildlife/mammals/greysquirrel.html
http://www.yptenc.org.uk/docs/factsheets/animal_facts/grey_squirrel.html
http://www.noahsarkgardens.co.uk/Wildlife/Mammals/GreySquirrel.htm
http://www.absoluteastronomy.com/encyclopedia/a/ac/acorn.htm
http://www.squirrels.org/t_gray.html
http://www.crainranch.com/nutrition.htm
http://www.nuthealth.org/
http://www.treenuts.org/

Journals:
-Foods and foraging behaviour of red (Sciurus vulgaris) and grey (Sciurus carolinensis) squirrels. Moller H (1983) MammalRev 13:81Ð98
-The American Midland Naturalist Volume: 142, Issue: 1, July 1, 1999. pp. 102-109. SHEALER, D. A., SNYDER, J. P., DREISBACH, V. C., SUNDERLIN, D. F., NOVAK, J. A.
-The American Midland Naturalist Volume: 148, Issue: 2, October 1, 2002. pp. 271-281. SPRITZER, MARK D.
-Journal of Animal Ecology Volume: 73, Issue: 1, January 2004. pp. 26-35.
-Optimal distances for squirrels to transport and hoard walnuts. Gurnell, John, Wauters, Luc A., Lurz, Peter W. W., Tosi, GuidoTamura N, Hashimoto Y, Hayashi F (1999) Animal Behavior 58:635Ð642
-Food habits and caching behavior of urban grey squirrels. Thompson DC, Thompson PS (1980). Can J Zool 58:701Ð710
-Density-dependent survival of scatterhoarded nuts: an experimental approach. Stapanian MA, Smith CC (1984) Ecology 65:1387Ð1396

Books:
ÒEcology and Evolutionary Biology of Tree Squirrels,Ó
Edited by Michael A. Steele, Joseph F. Merritt and David A. Zegers.
Virginia Museum of Natural History, Martinsville, Virginia.
Species Publication Number 6, 1998.

ÒNorth American Tree Squirrels,Ó
Michael A Steele, John L. Koprowski.
Smithsonian Institution Press, Washington and London, 2001.

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