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Old "FOTW" entries and blog archives
Ichthyology:
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01/22/03
My favorite reef fish is Aspidontus taeniatus, the false cleaner blenny. Its other name, sabertooth blenny, gives a vivid description of its nature. Through deception and wicked co-adaptation, the false cleaner, much like a backstabbing bureaucrat from some dark corporate vision, lures fishes in and then ravages them.
How does this unassuming little thing achieve this nefarious lifestyle? By posing as a cleaner wrasse (Labroides dimidiatus). Cleaner wrasses set up small territories on coral reefs, into which any fish, no matter its size or method of eating, can come and get groomed by the assiduous wrasse. Giant groupers sit calmly, gills and mouth agape, as wrasses pick over tongue and teeth, removing bits of old food and debris. Once they've had an all-over cleaning, fishes leave the station and all promises of good behavior are off. It's really rather remarkable.
Into this harmonious scene wriggles the false cleaner blenny. Nearly identical in shape, size, and color to the cleaner wrasse, the blenny will even assume the characteristic vertical position in the water that the wrasse uses to let others know the station is open for business. But when a fish arrives for a good grooming, it's in for nothing but nips and bites, as the vampiric blenny munches away at its very flesh.
More False Cleaners
01/13/02
For a long time, it was a mystery why icefish, known to whalers as "white crocodile fish," didn't freeze solid in 28° F Antarctic waters. Now we know that not only does their blood contain a natural antifreeze, but they also have no hemoglobin, indeed no red blood cells at all. That's why they're often so pale in color.
Big glycopeptides lower the freezing point of water inside the icefish's body, keeping them from dying. Likewise, if their blood was hemoglobin-rich like ours, they wouldn't get enough oxygen to their tissues, as hemoglobin doesn't work well at low temperatures. Evolutionary pressure has instead given the icefish an enlarged heart and wide blood vessels to carry their relatively thin blood.
More Icefishes
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