Course: Lab Animal Behavior    ...

Course: Lab Animal Behavior

                                         Analysis of movement in Chitons

Introduction: 

  Several species of Chiton are known to exhibit homing behaviors, journeying to feed and then returning to the exact unique spot they previously inhabited.  The specific method of how chitons can perform such behaviors has been investigated to some extent, however thereason remains unknown. Suggestions include the chitons remembering the topographic profile of the region, thus being able to guide themselves back to their home scar via a physical knowledge of the rocks and a visual input by their primitive eyes,The gastropod[->0] Nerita textiles is known to deposit mucus as it moves, which a chemoreceptive organ is able to detect and guide the snail[->1] back toits home site,  It is unclear if chitons function in this manner. However, it is theorized that they may leave chemical cues along the rock surface and at the home scar which olfactory senses can detect and home in on. Furthermore, old trails may be detected, providing further stimulus for the Chiton to find its home.

Abstract: 

To determine if chitons of the Dominican Republic return to theirhome scars.

       Chitons are a type of mollusk, characterized by a segmented shell. The top of its body has eight overlapping shells. Chiton live on rocky shorelines and shallow, shelly ocean bottoms. When in danger, the chiton can roll itself into a ball exposing its hard shell. Chitons move the same way as snails move, using a soft appendage known as a foot to apply suction to the surfaceover which the chiton is moving. This allows the chiton to firmly hold to the rocks as it feeds. Chitons use their sharp teeth to scrape algae off the rocks at night. Chitons eat algae, seaweed debris, dead animals, small worms and crustaceans. Chitons can be 2cm to 33 cm.

Material and Methods: 

    At the low tide on Tambora Beach in Samana Bay in Samana, Dominican Republic a  a rock withvarious chitons was chosen to observed them very carefully. Using a tape measure in mm. The length and width of each chiton was measured. The distance of each chiton from top, bottom, and side of the rock was then measured in cm. At the next low tide the same measurements were made again in order to determine if the results were the same or not to determine if Chitons of the Dominican Republicreturn to their home scars.

Results: 

        

The results show that after examine 2 Chitons in two different rocks for 3 days, they really moved. According to the measures the two chitons don’t do that far but they have significantly moves back to their “home scars” that were measured and are show below:

  Chiton 1 ROCK A                                   ||||
|Day 1|Day2|Day3|Width|25mm|25mm|2mm|
Length|14.5mm|14.5mm|3.5mm|
From Top of the rock|              20cm|     24cm|19cm|
From Bottom of the rock|45cm|51cm|47cm|
From Left of the rock |67cm|70cm|66cm|
From Right of the rock |40cm|37cm|41cm|

  Chiton 2 ROCK B                                   ||||
|Day 1|Day2|Day3|
Width|23mm|25mm|2mm|
Length|11.5mm|14.5mm|3.5mm|
From Top of the rock|              25cm|    26cm|23cm|
From Bottom of the rock|57cm|59cm|55cm|
From Left of the rock |71cm|70cm|73cm|
From Right of the rock |30cm|33cm|32cm|

Discussion: 

     We can accept the fact that an animal can find its way home, or a bird can navigate for great distances on migration; we can easily prove that a squirrel can scamper back to its den in a hollow tree, even when hundreds of similar trees are inclose proximity, or that a fox can return to its cave, even though the animal may range out for several miles. We agree that any animal with a brain, even a half-brain, regardless of how elemental it may be, does however, have sense enough to find its own nest, den or individual spot where it rests or feels safe. But there are living creatures  without the slightest trace of brain that return to a...