07/25/2005: Amazing Elasmobranchs...
This is quite a summer for SHARKS and Smithsonian (August 2005) has a Kool one about Sharks with an article: The Surprising Science of Sharks with loads of interesting tid-bits of information [which I read even though I can’t (can’t) look at the pictures.]
Consider a few of these great facts about these Selachophobe Nightmares:
-- Sharks belong to a group of fishes known as Elasmobranchs that also includes rays and skates. Elasmobranchs lack an air bladder that give other fish bouyancy, and their skeletons are made of if light cartilage instead of bone.
-- John McCosker’s adventurous fieldwork in the 1980’s confirmed other’ research that indicated Great Whites, unlike most fish, are warm-blooded (as are makos and salmon sharks).
-- During three decades spent swimming with hammerheads, Peter Klimley, now a biologist at the U of C at Davis, concluded that they navigate by sensing magnetic “roads” that radiate from underwater mountains.
--- Shark skin is covered with millions of tiny toothlike scales called dermal denticles. They not only make the skin rough; they increase the durability and may help to reduce drag.
-- The tiny black dots cover their heads like a five o’clock shadow are pores that lead to the ampullae of Lorenzini, named after the Italian biologist, Stefano Lorenzini, who described them in 1678. The pores connect to canals filled with conductive gel and then sensory chambers that detect tiny electric fields animals give off.
--- Like other fish, sharks also sense vibrations through their lateral lines, the receptors that run beneath the skin from tail to snout.
-- The animals’ legendary sense of smell can detect blood and body fluids suspended in the water in minuscule amounts – down to parts per billion.
Pretty awesome facts. But, sadly the article is also about the worldwide over-fishing and endangerment of certain species of Sharks. It would cause a severe ocean wide ecosystem problems to have these populations permanently depleted – but I can still hope to keep them out of my Nightmares in all their forms and species.
Karen on 07.25.05 @ 07:44 AM CST