Cranberry Lake Biological Station

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One major defensive mechanism of American Toads (Anaxyrus americanus) against predation is cryptic coloration; they undergo a color change to match their substrates. The observation of a distinct white stripe on some Adirondack toads led us to question how the stripe impacts the toad’s ability to match substrate color. We hypothesized that American Toads with a distinct white stripe will have a faster rate of color change (measured in change of MCV’s per minute) than American Toads without white stripes. Due to the difference in sizes of the toads, we also hypothesized that smaller toads would undergo a faster color change (change in MCV’s per minute) due to their smaller surface area. Thirty-one toads were collected after sunset on the trails immediately surrounding the campus. These toads served as both the experimental and sampling units. They were brought back to the lab and color change was tested from a light to dark tank over a total of 3 hours. One two sample T-test and one regression analysis were used to statistically analyze the data for hypothesis one and two, respectively. The mean findings for the presence or absence of a white stripe on rate of color change will be presented and discussed, as well as the hypothesis on color change rate based on size. The findings from this experiment could potentially explain how the diverse coloration of Adirondack toad populations persist with distinct markings.



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