Age and Sex Differences in Exploratory Behavior of Prairie Voles, Microtus ochrogaster AnnaLynn Harris*, Danielle N. Lee+, and Zuleyma Tang-Martínez+*Normandy Senior High School, St. Louis, Missouri + Department of Biology, University of Missouri-St. Louis

1. Age and Sex Differences in Exploratory Behavior of Prairie Voles, Microtus ochrogaster
AnnaLynn Harris*, Danielle N. Lee+, and Zuleyma Tang-Martínez+
*Normandy Senior High School, St. Louis, Missouri
+
Department of Biology, University of Missouri-St. Louis
Questions
Research Background 1. Which sex, males or females, will explore the maze more?
EXPLORATION & EXPLORATORY BEHAVIOR 2. Will younger or older prairie voles explore the maze more?
Exploratory behavior means finding out what your surroundings are without any obvious motivation.
By exploring an individual gains information about potential food, shelter, and mates. However,
individuals may also encounter predators. The objective of this study was to determine how prairie
voles respond in a novel environment. A multi-arm exploratory maze was used because it mimics the
Hypotheses Photo credit: Betty McGuire
www.science.smith.edu
/department/biology/faculty. bmcguire.html
MO-STEP is a GK-12 program funded by the National Science
Foundation. Graduate students work with K-12 educators in Science,
voles’ natural habitat. 1. Exploratory behavior between male and female prairie Technology, Engineering, and Mathematics fields to enrich the existing
curriculum and to promote collaboration between secondary and post-
MALE/FEMALE DIFFERENCES in EXPLORATORY BEHAVIOR voles will differ. secondary institutions of learning. Through these partnerships, K-12
students are able to conduct authentic science investigations. Ms.
In other types of exploratory and activity tests with rodents, differences in male and female behavior
have been reported. Some previous studies have found there are differences between males and
2. Older prairie voles will be more exploratory than the Harris is a senior at a participating high school and was mentored by
Ms. Danielle Lee, who served as a graduate fellow in her Biology class.
females; however, other studies have found no differences. Some of the conflicting results could be younger prairie voles.
due to different types of species studied (rats, voles, and, mice). The objective of this study was to
determine how male and female prairie vole exploratory behavior differs when introduced to a novel
environment. Results & Conclusions
AGE DIFFERENCES IN EXPLORATORY BEHAVIOR Results Figure 1: Males and Females did not differ in any of the variables measured.
Previous exploratory and activity studies with rodents have shown that when comparing younger to
older individuals, older subjects are more exploratory and more active. The objective of this study was
to determine how the differences among a wide range of age groups influences exploratory behavior.
General Methods
1. Place subject in the start box and allow it to acclimate for 3 minutes.
2. Open the door to start box.
3. Time how long it took for subject to leave the start box, allowing up to
2 minutes. N = 46 N = 34
4. Record the number of times each arm, dead end, and start box was
visited. Average time to enter the maze, number of visits to each arm, and number of visits to each terminal, including the start box, were not significantly different when comparing
males to females (statistical analyses Univariate ANOVA for Latency, Repeated Measures ANOVA for visits to arms and terminals).
5. Total test time was 3 minutes.
In summary, males and females were equally active and exploratory when introduced to a novel environment. We fail to support our hypothesis that exploratory
Individuals were tested only one time. behavior differs between male and female prairie voles.
There was no food or other reward in the maze.
Experimental Design Results Figure 2: Older voles differ from younger voles for all variables measured.
Subjects
• Female and male prairie voles from Materials
3 age groups • Exploratory Maze
• Young: 55 to 180 days • Stopwatch
• Middle Age: 181 to 365 days • Timer
• Older: More than 1 year of age • Data sheets
Independent Variables
• Sex of subjects
• Age of subjects
N = 26 N = 42 N = 12
Schematic of the Maze
Average time to enter the maze, number of visits to each arm, and number of visits to each terminal, including the start box were different when comparing young to middle age
to old animals (statistical analyses Univariate ANOVA for latency, Repeated Measures ANOVA for number of visits to arms and terminals).
Dependent Variables
• Latency to leave start box in seconds Fig 2a. Although latency to enter the novel environment was not statistically different, there is a strong trend. For Figures 2b and 2c, common letters reflect statistical
• Number of times each maze arm visited relationships between groups. Fig 2b. Young individuals visited the arms fewer times than both middle age animals (a: P = 0.027) and old animals (b: P =0.012) , Fig 2c. Young
animals also visited the terminals of the maze fewer times than old animals (a: P = 0.05).
- arms 1, 2, & 3
• Number of times each maze dead end In summary, our results suggest a strong relationship between age and level of activity and exploratory behavior in novel environments. We are able to support our
visited hypothesis that older individuals are more exploratory than younger individuals. We suggest that as individuals become older they may become less averse to
exploring novel environments.
- dead end 1 (15 cm from start box)
- dead end 2a (560 cm from start box)
- dead end 2b (500 cm from start box)
2
Anna Harris presented this research poster at Acknowledgements
- dead end 3a (835 cm from start box) the 43rd Annual International Conference of NSF, MO-STEP, UMSL Department of Biology, Patricia Hinton, Maryann Hempen,
- dead end 3b (1095 cm from start box)
3 Ar 1 the Animal Behavior Society in Snowbird, Patrick Osborne, Zuleyma Tang-Martínez, George Taylor, Susan Fortenbury,
• Number of times the start box revisited
ms Utah, August 12-16, 2006. Elizabeth Congdon, Miguel Bedoya, Javier Hernandez, Marcela Fernandez,
Dianna Voorhies, Family and Friends
Start
box