1. Habitat Selection in Hermit Crabs
Erika McLellan
Erin Henderson
Michelle Johnson
Meghan Keddy

2. Background Hermit crabs prefer dark, moist environments
They choose discarded shells
Shell size may affect habitat preference
Sediment texture influences habitat selection
They will bury themselves into the sand before they molt and for protection

3. Hypothesis
We predicted the hermit crabs would show preference for a different substrate than sand

4. Methods
10 crabs were taken out of holding tank and placed in a tank with small amount of warm water
Bin filled with leaves, rocks, and sand: 6 trials
Dark room (red light)
Each crab was placed in center substrate one at a time
Stopwatch was started: time was recorded when movement began, and crabs were observed for 5 minutes
ANOVA and Tukey Test used to determine if there was a significant difference in the average percent time the crabs spent in each substrate

6. Crab Details Largest crab: 5.5 cm Smallest crab: 2.5 cm
Varying shell types

7. Results Testing time of 15275 seconds
Total time (s) spent in each substrate
Percent time: Rocks 32%, Leave 52%, Sand 16 %

8. Average percent time spent in each substrate
Rocks: 33.6% , Leaves: 46.5%, 18.34%

9. Rocks vs. Leaves vs. Sand
ANOVA test determined that there was a significant difference in the average % time spent between substrates (p = )
Tukey Test determined:
Rocks vs. Sand: not significant
Rocks vs. Leave: not significant
Sand vs. Leaves: significant

10. What does it all mean… Overall assumption Prediction
Sand is the preferred habitat
Prediction
Rocks and leaves will be preferred over sand

11. Rocks Rocks not statistically different than the leaves or sand
Observed behaviour
Along vs. on top of rocks
Reasons
Camouflage?
Size related?

12. Leaves The hermit crabs spent half their time in the leaves.
Observed behaviour
Moved underneath the leaves
Reasons
Moist and humid
Shelter?

13. Sand The hermit crabs spent the least amount of time in the sand.
Observed behaviour
Burrowing
Reasons
Protection
Molting

14. Conclusion Crabs will pick leaves over sand
Cannot say if they would pick rocks over sand
Cannot say if they would pick leaves over rocks
Their preference for leaves may be because leaves offer the same coverage and protection as sand, but it takes less energy to hide in.

15. Limitations Used an bottom layer of sand across the entire bin
Should have created barriers
The smell of the leaves
Could have used fake leaves
Including time in shell in 5 min
Should have started 5 min trial when they began to move