Friday, March 2, 2012

Crayfish Chronicles pt. 1

Hey ya'll! 

No classes for me to teach today so besides responding to my students emails, I decided to just kick back, relax and enjoy the beginnings of a really long weekend. And what better way for me to do that really than to observe some of the animals in my study! With the semester having begun to kick off in full force, I really don't have much time to study my animals during the course of the week so when I do get to go home and take some time off for myself, there is nothing really that I would enjoy doing more than observing these little critters at work. Now one of the best things about having these live animals to observe in my study is really how I grow to be so familiar with them and their habits but this relationship work both ways as they grow more and more accustomed to having me poke and pry about their habitats as times goes by. Documenting them for the purposes of sharing, therefore becomes a lot easier than say, if I had to go out and search for them in the wild. Keric, my rosea tarantula, for example has become a lot more agreeable to me snooping about and photographing him in his tank and our praying mantis will now even consent to accepting pieces of food in exchange for her compliance to being handled on a regular basis. But as tempted as I was to amuse myself with my insect and arachnid companions, I had a crustacean to deal with and a rather aggressive one too! 

Marina, our freshwater lobster, or crayfish arrived only just yesterday and though probably still needs a few more days to settle in completely, was "comfortable" enough in her new home to claim a corner of it for herself by waving her pincers menacingly whenever I move nearby. If you look at a crayfish from up close you can see that the actual amount of appendages it possesses are really quite astounding. Aside from the two main feelers which it uses pretty much the same way a blind man might use his walking cane, they posses several pairs of smaller ones that extend just in front of their mouth as well. These, I've discovered, seem to react to scent or whatever it is that passes for "smell" under water and twitch enticingly if a turtle pellet is held nearby. After these come the pincers or claws, these are really just highly developed pairs of modified legs and if you were to pick up one of these crayfish and flip it upside down you will see that the other legs possess miniature versions of the front claws as well. Indeed, for an animal covered almost entirely by a tough shell-like carapace, crayfish are really quite sensitive to touch and they achieve this by the little bristles that stick out of their shell which act as receptors that measure sudden changes in water currents and their surroundings to let them know if any prey are nearby as Marina so expertly demonstrated when I experimentally dropped a mealworm into the opposite end of her tank.

But while these marvelous appendages are usually used in hunting and in self defense, they are more than adequately equipped for constructing crayfish-homes as well, as I observed today, and they do this mainly by behaving in the same manner as a bulldozer: by digging their front most claws slightly into the ground, and then shoving forward with all their might, using two or three pairs of their smaller legs to gather silt and gravel underneath them as they move along. Indeed, this seems to be a process that is most laborious for such a small creature, but Marina now has a comfortable little "trench" into which she retreats to whenever she feels insecure and threatened which leads me to my other observation that for a bottom-dwelling, mostly nocturnal animal, they seem to have a rather remarkable sense of sight considering how my fingers hovering almost 10 inches away is enough to elicit a claw-waving response from Marina! 


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