Observations and Hypotheses Homework KEY
Goes with reading 1.3 & 1.4 from Neil 9e
“Red on yellow, kill a fellow. Red on
black, venom lack.” Based on this
rhyme, what kind of snake is shown
below?
1. Identify the following in the snake mimicry experiment conducted by
D. & K. Pfennig and W. Harcombe:
 Question
What is the function of mimicry? In other words, why does the harmless scarlet king snake
resemble
the poisonous eastern coral snake?
 Hypothesis
The scarlet king snake’s coloration evolved to decrease its risk of being preyed upon; predators
mistake it for a coral snake and leave it alone. This is not a learned behavior; it is instinctive (in
the gene pool of the predator). Stated as a prediction: If artificial coral snake mimics are placed
in areas both with and without coral snakes, then in areas with coral snakes, the king snakes
should be attached less often than in areas without coral snakes.
 Independent (manipulated) variable
Snake model color (rings of red, black and yellow); also, whether the area did or did not have
eastern coral snakes.
 Dependent (responding) variable
Percentage of attacks on the artificial snakes (by foxes, coyotes, raccoons and bears)
 A controlled variable
Both the artificial king snake models and the brown snake models were made of plastic-coated
wire. (Others might be: both models were bent into the same position, or placed on the ground,
or were life-sized, etc.)
 Experimental group
The artificial scarlet king snakes
 Control group
The artificial brown snakes
 Findings
In areas with coral snakes, attacks on the artificial scarlet king snakes (the coral snake mimics)
made up 16% of all fake snake attacks, while attacks on artificial brown snakes made up 84% of
all fake snake attacks. In areas without coral snakes, artificial scarlet king snake attacks were
83% of the total attacks and artificial brown snake attacks were 17% of total attacks.
There are some important controls at work in this experiment. If we didn’t have those ALL data,
we might think that the first area just had fewer predators in general, or that bright colors repel
foxes, coyotes and raccoons…
2. What might be a potential technological application of the snake mimicry experiment?
Perhaps hiking footwear or food storage containers could be made of plastic the same color as
coral snakes, to discourage fox/coyote/raccoon/bear attacks.
Or, maybe fake snake models could be used as a gauge of predator aggression or density in a
given area.