The Great Elephant Census
Scientists at Work
Student Worksheet
OVERVIEW
This worksheet complements the short video The Great Elephant Census from the Scientists at Work series.
PROCEDURE
1. Prior to watching the video, read the questions below.
2. Watch the video.
3. If working with a partner or in a small group, discuss and answer the questions below. If working alone,
QUESTIONS
1. What are the two main threats to African elephant populations?
Scientists estimate that African elephants are being lost at a rate of ________/day.
2. What are two principal research questions that will be addressed by the Great Elephant Census?
3. Logistics are the details that must be handled to plan and organize a complicated activity or event that
involves many people. Give three examples of logistics that the organizers of the census need to
4. How will the results from the project be used?
5. Dr. Mike Chase’s team has chosen to use a sample count method to estimate the total elephant
population size. Why did they choose sampling over a total count of each elephant?
6. Accurate counts are critical because they are used to estimate the total population. List three things that
the researchers do to ensure accurate sample counts.
7. What technology is the team using to determine which elephants are inside and outside the strip?
What human limitation makes this necessary?
Elephants Collection
Revised September 2017
www.BioInteractive.org
Page 1 of 2
Scientists at Work
The Great Elephant Census Student Worksheet
8. Apply what you learned from the film:
The Great Elephant Census involved over 100
scientists working in many countries. Within
each country, they divided survey areas into
regions, called strata, of varying shapes and
sizes. Teams then flew along transect lines to
estimate the number of elephants in each
stratum. The lines in the diagram to the left
represent the transects that a plane follows
during an aerial survey of each stratum. The
counting strips are 150-m-wide areas on either
side of each transect where elephants are
counted. The table below shows the data that
were collected for one stratum.
Transect
Transect
length (km)
Width of
counting strip
(km)
Counting
strip area
(km
2
)
Elephant density
in counting strip
(#/km
2
)
A
9.1
0.3
2.7
0.37
B
22.5
0.3
6.8
0.59
C
27.2
0.3
8.2
0.86
D
22.8
0.3
0
E
32
0.3
9.6
0
F
21.4
0.3
6.4
0
G
29.6
0.3
8.9
0.45
H
20.2
0.3
6.1
0.83
I
22
0.3
6.6
0
J
9.2
0.3
2.8
0
K
4.6
0.3
4
Average Elephant Density for Stratum (round to nearest hundredth)
a. Calculate the missing values in the data table. Here are a few formulas to help you out
Area = length × width Population Density = # of animals/area
Average = sum of all of the densities/# of transects
b. The total stratum area is 803.7 km
2
. Using the mean elephant density for the stratum that you
calculated, calculate an estimated # of elephants that could be found in this stratum.
c. What might explain the wide range of elephant densities among the different transects of the stratum?
Give two reasons, one that relates to elephant behavior and one that relates to the survey design.
Elephants Collection
Revised September 2017
www.BioInteractive.org
Page 2 of 2