Weight’s Effect on Weight’s Effect on Predation Predation

May 31, 2007May 31, 2007

Sandra Archibald, Lindsay Camm, Sandra Archibald, Lindsay Camm, Kenny Limber, Bhumit PatelKenny Limber, Bhumit Patel

Where and When?Where and When?

The project was performed on Thursday The project was performed on Thursday May 24, Friday May 25May 24, Friday May 25thth, and Sunday , and Sunday May 27May 27thth

Performed outside of SAHB Building near Performed outside of SAHB Building near Lake GarnettLake Garnett

Dogs were brought in on separate daysDogs were brought in on separate days Same quadrant was used for each Same quadrant was used for each

individualindividual

MaterialsMaterials

Different breeds and ages of dogs on leashesDifferent breeds and ages of dogs on leashes Two boxes or Purina Brand Milk bones for Small DogsTwo boxes or Purina Brand Milk bones for Small Dogs 1 clipboard1 clipboard 1 helper person1 helper person 2 stop watches (one for 5 minute time and 1 for 2 stop watches (one for 5 minute time and 1 for

handling time)handling time) 1 pen1 pen 1 tape measurer that does at least 20m1 tape measurer that does at least 20m 4 flags to mark off quadrant ( or trees )4 flags to mark off quadrant ( or trees ) 1 bottle of water for recorder to drink1 bottle of water for recorder to drink

MethodsMethods

Dogs were left on leash to complete projectDogs were left on leash to complete project Dogs “hunted down” the prey in the 10m x 10m Dogs “hunted down” the prey in the 10m x 10m

quadrantquadrant Three handling times were recorded per dogThree handling times were recorded per dog Counted the number of treats eaten in 5 minutesCounted the number of treats eaten in 5 minutes Recorded the weight of the dog before Recorded the weight of the dog before

experiment beganexperiment began The control in this experiment was the weight of The control in this experiment was the weight of

the dogthe dog

Gabriel Hunting for treatsGabriel Hunting for treats

MapMap

DataData1/Pc 1/Pc

WeightWeight Prey Consumed ObservedPrey Consumed Observed 1/Weight1/Weight 1/Pc1/Pc expectedexpected Pc ExpectedPc Expected

101101

16160.0090.009

99

0.060.062255 0.06560.0656 15.240715.2407

8686 16160.0110.011

66

0.060.062255 0.06720.0672 14.884014.8840

7070 14140.0140.014

33

0.070.071144 0.06960.0696 14.366614.3666

6767 990.0140.014

99

0.110.111111 0.07020.0702 14.247414.2474

6767 17170.0140.014

99

0.050.058888 0.07020.0702 14.247414.2474

6363 18180.0150.015

99

0.050.055566 0.07110.0711 14.074414.0744

5858 15150.0170.017

22

0.060.066677 0.07230.0723 13.831913.8319

4848 13130.0200.020

88

0.070.076699 0.07560.0756 13.233313.2333

2626 13130.0380.038

55

0.070.076699 0.09160.0916 10.915210.9152

1515 880.0660.066

77

0.120.125500 0.11730.1173 8.52568.5256

1414 660.0710.071

44

0.160.166677 0.12160.1216 8.22188.2218

1313 10100.0760.076

99

0.100.100000 0.12660.1266 7.89707.8970

1313 990.0760.076

99

0.110.111111 0.12660.1266 7.89707.8970

ResultsResultsThe Linear Effect of Weight on Amounts of Prey Consumed

y = 0.9104x + 0.0566

0.0000

0.0200

0.0400

0.0600

0.0800

0.1000

0.1200

0.1400

0.1600

0.1800

0.0000 0.0200 0.0400 0.0600 0.0800 0.1000

1/W

1/P

c Series1

Linear (Series1)

Comparing Two ValuesComparing Two ValuesPc ExpectedPc Expected15.2415.2414.8814.8814.3614.3614.2414.2414.2414.2414.0714.0713.8313.8313.2313.2310.9110.918.528.528.228.227.897.897.897.89

Prey Consumed Prey Consumed 16161616141499171718181515131313138866101099

Closeness of Two ValuesCloseness of Two ValuesThe Effect of Weight on Amounts of Prey Consumed

y = 3.7439Ln(x) - 1.5687

y = 3.8507Ln(x) - 1.4654

0

2

4

6

8

10

12

14

16

18

20

0 20 40 60 80 100 120

Predator Weight (W)

Pre

y C

on

sum

ed (

Pc)

Log. (Pc Expected)

Log. (Pc Observed)

The results shown on the graphs The results shown on the graphs illustrate that the experimental data is illustrate that the experimental data is consistent with the expected data. consistent with the expected data.

As the predator weight increased, the As the predator weight increased, the amount of prey consumed increased as amount of prey consumed increased as well.well.

Our HypothesesOur Hypotheses

Null Hypothesis: There is no relationship Null Hypothesis: There is no relationship between the weight of a predator and the between the weight of a predator and the efficiency of a predator.efficiency of a predator.

Alternative Hypothesis: Predator Alternative Hypothesis: Predator efficiency varies between different efficiency varies between different weights of predators.weights of predators.

The Results Support...The Results Support...

The results show a correlation between The results show a correlation between predator weight and the amount of prey predator weight and the amount of prey consumed. consumed.

The data accepts the alternative hypothesis The data accepts the alternative hypothesis and rejects the null hypothesis. and rejects the null hypothesis.

A correlation can be drawn to show that the A correlation can be drawn to show that the more a predator weighs, the more prey it can more a predator weighs, the more prey it can hunt and consume.hunt and consume.

Possible Sources of ErrorPossible Sources of Error

Some dogs may have had a preference Some dogs may have had a preference for different treats (a.k.a. prey).for different treats (a.k.a. prey).

Because of the dogs’ schedules, subjects Because of the dogs’ schedules, subjects were tested on different days. were tested on different days. Environmental factors may have played a Environmental factors may have played a part in predator behavior on various part in predator behavior on various days.days.

For Further For Further Experimentation...Experimentation...

To improve this study, researchers could To improve this study, researchers could increase the number of subjects to make increase the number of subjects to make the results more reliable. the results more reliable.

All subjects could be tested on the same All subjects could be tested on the same day. day.

More factors could be taken into More factors could be taken into consideration like the breed of dog and consideration like the breed of dog and the size of the predator’s mouth.the size of the predator’s mouth.

In Conclusion...In Conclusion...

A positive correlation has been made between A positive correlation has been made between predator weight and the amount of prey predator weight and the amount of prey consumed in a given time.consumed in a given time.

We conclude that larger dogs are more We conclude that larger dogs are more efficient predators. They have larger appetites, efficient predators. They have larger appetites, requiring more prey to be consumed before requiring more prey to be consumed before they meet satiation. They generally have they meet satiation. They generally have larger mouths, allowing them to eat faster. larger mouths, allowing them to eat faster. Larger dogs utilize their time better to find as Larger dogs utilize their time better to find as much prey as possible.much prey as possible.