Introduction
The question we were trying to answer was �Do hermit crabs have a preference for a specific species of snail shell, or do they just use what is most abundant? And would this data change in respect to the specific zone the hermit crab was found in?� We wanted to know if they would show a preference because this would mean that there would be more of a competition for a certain type of shell if they do. Our hypothesis was that hermit crabs would not show a preference at all, but would use the largest amount of shells found in the region in comparison to the amount of that snail species present. Other studies found that� A brief summary of our research methods were; we collected the first 35 hermit crabs and the first 35 snails per person found under rocks in zone 2. We compared the amount of shells of various species of the hermit crabs, and then counted the number of various snail species. After we had collected this data, we compared the two data sets. To broaden our data pool and increase our accuracy, we performed the same experiment in zone 3 as well. It seems as though there are a lot of studies that have been done to compare hermit crabs with snails; however, many of those studies were not relevant to what our question was. We did find a number of studies giving reference to the same question as ours many of which came from out of the Gulf of California. We did find a few studies that were in the area with the same question as our experiment.
Methods and Materials:
There were a few different materials used while conducting our group�s experiment. These materials included three large rectangular Tupperware containers and three round bowls. We used both kinds of containers to collect the specimens in. Our group conducted research at Station Beach in Rocky Point. We decided to collect snails and hermit crabs along two different zones. The first round of specimen was collected at low tide at about ten o�clock at night. At this time the snails and hermit crabs were collected along zone 2. This was determined by the large basalt rocks and the beginning of the tide pools. Each group member collected 35 snails and 35 hermit crabs, keeping the hermit crabs and snails separated. All of the animals were collected from the underside of rocks. After each group member finished collecting their data we returned to the beach. We then kept each individual�s animals separate and began to collect the data. Starting off with the snails, we went through and determined each species. We separated the species into piles then proceeded to count the number of snails in each species pile. After this was repeated for each group members� collection of snails we moved on to hermit crabs. Like the snails, we went through and determined which species of snail shell the hermit crab was occupying. After doing so, we then separated the hermit crabs just as we did the snails. After determining each species we counted the piles. After all the initial counting was finished we combined the entire group�s data and came up with our final numbers. The following day the group returned to Station Beach to set up the same exact research plan. However the data was now collected in zone three rather than zone 2. It was around 9am while we were collecting at low tide. We determined zone three by some small barnacles. Also towards the end of collecting we determined it as being near the water because the tide was coming in.
Results
Shell Use - Zone 2 Observed
| Common Name | Types of Shell | Hermit Crabs | Snails | Total Shells | Standard Deviation |
| Turban Snail | Turbo fluctuosus | 40 | 42 | 82 | 1.41 |
| Marian's Top Snail | Tegula mariana | 30 | 35 | 65 | 3.54 |
| Nerite | Nerita funiculate | 14 | 8 | 22 | 4.24 |
| Angelic Tooth Snail | Acanthina angelica | 4 | 14 | 18 | 7.07 |
| Speckled Cerith | Cerithium maculosum | 4 | 3 | 7 | 0.71 |
| Fly-Speck Cerith | Cerithium stercusmuscarum | 5 | 0 | 5 | 3.54 |
| Inflated Dove | Columbella fuscata | 2 | 0 | 2 | 1.41 |
| Coraline Snail | Morula ferruginosa | 5 | 3 | 8 | 1.41 |
| Anachis | Costoanachis sp. | 1 | 0 | 1 | 0.71 |
| Pygmy Olive | Olivella dama | 0 | 0 | 0 | 0.00 |
Fig. 1. Each column is an average of the three samples of each species, hermit crabs and snails, collected by three people, collecting only the species from under rocks in the intertidal zone 2 of Station Beach at Puerto Penasco, Mexico. Averages are +/- 0.76 standard error.
Shell Use - Zone 2 Expected
| Common Name | Types of Shell | Hermit Crabs | Snails | Total Shells | Standard Deviation |
| Turban Snail | Turbo fluctuosus | 41 | 41 | 82 | 0.00 |
| Marian's Top Snail | Tegula mariana | 32.5 | 32.5 | 65 | 0.00 |
| Nerite | Nerita funiculate | 11 | 11 | 22 | 0.00 |
| Angelic Tooth Snail | Acanthina angelica | 9 | 9 | 18 | 0.00 |
| Speckled Cerith | Cerithium maculosum | 3.5 | 3.5 | 7 | 0.00 |
| Fly-Speck Cerith | Cerithium stercusmuscarum | 2.5 | 2.5 | 5 | 0.00 |
| Inflated Dove | Columbella fuscata | 1 | 1 | 2 | 0.00 |
| Coraline Snail | Morula ferruginosa | 4 | 4 | 8 | 0.00 |
| Anachis | Costoanachis sp. | 0.5 | 0.5 | 1 | 0.00 |
| Pygmy Olive | Olivella dama | 0 | 0 | 0 | 0.00 |
| Totals | 105 | 105 | 210 | Avg. = 0.00 |
Fig. 2. Each column is an expected average of the three samples of each species, hermit crabs and snails, collected by three people, collecting only the species from under rocks in the intertidal zone 2 of Station Beach at Puerto Penasco, Mexico. Averages are +/- 0.00 standard error.
Shell Use - Zone 3 Observed
| Common Name | Types of Shell | Hermit Crabs | Snails | Total Shells | Standard Deviation |
| Turban Snail | Turbo fluctuosus | 15 | 16 | 31 | 0.71 |
| Marian's Top Snail | Tegula mariana | 17 | 31 | 48 | 9.90 |
| Nerite | Nerita funiculate | 0 | 9 | 9 | 6.36 |
| Angelic Tooth Snail | Acanthina angelica | 12 | 10 | 22 | 1.41 |
| Speckled Cerith | Cerithium maculosum | 16 | 2 | 18 | 9.90 |
| Fly-Speck Cerith | Cerithium stercusmuscarum | 5 | 7 | 12 | 1.41 |
| Inflated Dove | Columbella fuscata | 2 | 0 | 2 | 1.41 |
| Coraline Snail | Morula ferruginosa | 35 | 29 | 64 | 4.24 |
| Anachis | Costoanachis sp. | 1 | 0 | 1 | 0.71 |
| Pygmy Olive | Olivella dama | 2 | 1 | 3 | 0.71 |
| Totals | 105 | 105 | 210 | Avg. = 3.6766955 |
Fig. 3. Each column is an average of the three samples of each species, hermit crabs and snails, collected by three people, collecting only the species from under rocks in the intertidal zone 3 of Station Beach at Puerto Penasco, Mexico. Averages are +/- 1.16 standard error.
Shell Use - Zone 3 Expected
| Common Name | Types of Shell | Hermit Crabs | Snails | Total Shells | Standard Deviation |
| Turban Snail | Turbo fluctuosus | 15.5 | 15.5 | 31 | 0.00 |
| Marian's Top Snail | Tegula mariana | 24 | 24 | 48 | 0.00 |
| Nerite | Nerita funiculate | 4.5 | 4.5 | 9 | 0.00 |
| Angelic Tooth Snail | Acanthina angelica | 11 | 11 | 22 | 0.00 |
| Speckled Cerith | Cerithium maculosum | 9 | 9 | 18 | 0.00 |
| Fly-Speck Cerith | Cerithium stercusmuscarum | 6 | 6 | 12 | 0.00 |
| Inflated Dove | Columbella fuscata | 1 | 1 | 2 | 0.00 |
| Coraline Snail | Morula ferruginosa | 32 | 32 | 64 | 0.00 |
| Anachis | Costoanachis sp. | 0.5 | 0.5 | 1 | 0.00 |
| Pygmy Olive | Olivella dama | 1.5 | 1.5 | 3 | 0.00 |
| Totals | 105 | 105 | 210 | Avg. = 0.00 |
Fig. 4. Each column is an expected average of the three samples of each species, hermit crabs and snails, collected by three people, collecting only the species from under rocks in the intertidal zone 3 of Station Beach at Puerto Penasco, Mexico. Averages are +/- 0.00 standard error.
Conclusion
After conducting the experiment and analyzing are data, the final observation we arrived at was that the hermit crabs did not show a preference on the particular species of snail shell they occupy. Rather, that they choose their shell according to the particular snail shell species with the greatest abundance in that area. The competition for shells seemed to be fierce. In some cases it seemed that the hermit crab may even get to the snail shell before the snail died. We came to this conclusion due to the relationship between the number of snail shells found and the number of hermit crabs found, and the similarities found between the two.