Rodent Riddle

Inferring internal states from external behavior

You might think that we can't know much about a mouse only from its temperature and activity level, but you'd be surprised! Let's practice learning from data by analyzing a few graphs:

When do mice sleep?

Activity Patterns Throughout the Day

When are mice most active? These pie charts reveal the distribution of mouse activity during light-on (day) and light-off (night) periods. Compare the overall activity patterns with those of male and female mice separately to discover behavioral insights.

Questions to consider: What does the size of each slice tell you about when mice are most active? Do you notice any significant differences between male and female activity patterns? What might this reveal about mouse circadian rhythms?

Our suggested answer: The visualization clearly reveals that approximately three-quarters (75%) of mouse activity occurs during light-off periods (night), demonstrating strong nocturnal behavior. This aligns with mice being naturally nocturnal animals who are most active when it's dark. Importantly, when comparing male and female mice, we observe remarkably similar activity distributions—both sexes show nearly identical proportions of day versus night activity. This suggests that circadian rhythm patterns are consistent across sexes in mice, with both male and female mice exhibiting the same strong preference for nighttime activity. The small variations between sexes (within 1-2%) are likely within normal biological variation rather than indicating meaningful behavioral differences.

Circadian Rhythm

This visualization shows mouse movement patterns and body temperature over multiple day/night cycles. The main plot (left) displays mouse positions and their movement (more active movement represent higher activity levels), while the right plot shows the relationship between temperature and activity levels. The color of each point represents the body temperature of the mouse.

Question to consider: How do the activity patterns of these mice across day and night cycles reveal their natural circadian rhythm?

Our suggested answer: The visualization reveals clear circadian patterns in mouse behavior. During light-off periods (night), mice consistently show heightened activity levels, coupled with elevated body temperatures (shown by warmer colors). Conversely, during light-on periods (day), their activity decreases significantly, and body temperatures tend to be cooler. This day-night activity pattern strongly indicates nocturnal behavior, which is an evolutionary adaptation common in rodents. The synchronization between activity levels and body temperature also demonstrates how circadian rhythms coordinate multiple physiological processes to optimize survival during their most active periods.

Can We Guess the Gender of a Mouse?

Do Male and Female Mice Have the Same Temperatures?

If we can find that the average temperature of male and female mice differ by a large amount, then we should be able to reasonably guess the gender of a mouse based on its temperature.

Question to consider: Can we guess mouse gender based on temperature and time? Will our guess always be correct?.

Our suggested answer: The temperature feature is useful in predicting mouse gender, since females tend to be hotter at each hour of the day. Still, after checking percentiles, it's clear that the hottest male mice are often hotter than the coldest male mice, meaning that there is no perfect value that separates the genders.

Activity Rankings: Gender Comparison

This visualization provides a comprehensive view of mouse activity patterns across day and night cycles, with a special focus on gender differences. The dual bar charts show activity levels during light-off (night) and light-on (day) periods, with mice automatically sorted by their activity levels. The visualization includes mini-plots showing the proportion of male vs female activity over time, allowing for detailed analysis of gender-based activity patterns.

Question to consider: How do the activity levels of male and female mice compare during different periods of the day, and what changes do we observe in female activity patterns during estrus days?

Our suggested answer: The visualization reveals interesting patterns in gender-based activity levels. Overall, male mice tend to show higher activity levels compared to female mice across both day and night periods. However, during estrus days, we observe a notable increase in female activity levels that extends beyond just the night period. While this increased activity doesn't surpass the overall male activity levels, it represents a significant behavioral change in female mice during their reproductive cycle. The mini-plots showing gender activity proportions help visualize these patterns, with the male proportion typically being higher but showing interesting variations during estrus periods. These findings suggest that while male mice maintain generally higher activity levels, female activity patterns are more dynamic and influenced by their reproductive state.

Can We Tell if a Female Mouse is in Estrus?

Effect of Estrus

This visualization shows the differences in body temperature and activity levels of female mice depending on the estrus period. The line chart shows the average body temperature of 12 female mice. Hovering reveals the activity level at each time point.

Question to consider: How does the estrus cycle affect female mouse body temperature and activity levels, and why?

Our suggested answer: The visualization reveals that estrus affects mouse temperature starting around 4 hours (240 minutes) after the light is turned off (night starts) and ends around 5 hours (300 minutes) after the light is turned on (day starts). During that period, the average temperature is 0.6°C higher than in other periods at maximum, which is quite significant considering that mice are homeothermic. Regarding activity levels, estrus also increases activity, but the affected duration is slightly different from body temperature changes. Around the same time body temperature increases, activity levels also increase, but they return to baseline around 1 hour after the light is turned on (day starts), which is earlier than the body temperature increase. Hence, we can conclude that estrus causes female mice to move considerably more to find male mice for breeding, which is one factor that increases body temperature. In addition, estrogen levels increase significantly during estrus. This leads to stimulation of the hypothalamus and thermoregulatory centers, which can raise the set point for body temperature and increase the basal metabolic rate (BMR), resulting in more internal heat production. Beyond the estrus day itself, we can observe that mice one day before estrus have higher body temperature and activity levels compared to other periods. This occurs because female mice begin to prepare for estrus. As we can see, estrus increases mouse body temperature and activity levels most significantly on the estrus day, but these changes begin one day before as well.

Test Your Knowledge!

Interactive Mouse Behavior Game

Think you understand mouse behavior? Test your scientific intuition! This interactive game challenges you to determine a mouse's sex and reproductive state (estrus) based solely on temperature and activity data. Just like real researchers, you'll need to identify patterns in physiological data to make accurate inferences about the internal states of laboratory animals.

Mice Data Interactive

Data is a powerful tool if you can learn how to plot it! Only using two attributes about mice, by creating interactive visualization, we were able to learn about their sleeping patterns, gender, and internal states. With a few more features, imagine what else we can discover.