Friday, January 20, 2012
Getting all Puffed Up
1. "It's so cute!" , 2. "Why doesn't it puff up?" and 3. "Isn't it poisonous?"
1. "Its so cute!" There is a lesson here - actually several. First off, they are cute because they have large eyes, lips and fins relative to their pudgy little bodies. These are human baby-like features that we relate too instinctively. It is why, when our children wake us up in the middle of the night for the fifth or sixth time, we do not shorten their life span in any fashion. There is an evolutionary imperative here to not take out our own young.
You can point this out to the visitors and ask them what the actual uses of these features are.
What does having large eyes tell us about the fish? Would you expect them to be day or night hunters? (large eyes = low light)
What about those lips and mouth - did you know that they have two vise-like crunching plates just inside those sensitive lips? These fish crunch up crabs, snails, and oysters like they are popcorn. Watch your fingers! Check out the jaw image here: http://australianmuseum.net.au/image/Porcupinefish-upper-jaw.
Watch how they move - like helicopters on the reef. The wide fins are invaluable for maneuvering around the reef to pluck off the crabs and such.
How do puffers inflate? They take a mouthful of water and swallow. A flap closes off the front of the mouth, so the water is forced down the throat to the stomach, which has a special pleated section on the belly side that can expand. It may take 14 to 20 quick gulps to fully bloat out.
Spiny puffers or porcupine fish have an additional defense in that they have spikey scales that are attached only at their base points with one long point free and lying flat on the skin. As the skin stretches, the long unattached point up these special scales is forced to rise up and stick out as a spine! For a great x-ray photo go here (x-ray-vision-fish-inside-out)and scroll through the photos to the porcupine fish.
3. "Isn't it poisonous?" Being poisonous is great, but as far as defenses go for an individual, it is of limited value (great to know that you took down whatever killed you, but a bit late). So, pufferfishes tend to be poisonous if eaten, but this is a third level defense with a pay off for the entire species rather than the individual.
porcupine fishes or your fish books at home, then let me know which type you think we might have.
Posted by HIMB CEP at 2:27 PM