• Question: Do sharks have bones?

    Asked by maddystich to Austin, Kirsty, Nicola, Nike, Sarah on 18 Jun 2012.
    • Photo: Kirsty Ross

      Kirsty Ross answered on 18 Jun 2012:

      No. A shark’s skeleton is made from cartilage, a material softer and more flexible than bone. Cartilage is found in the soft tip of your nose and the stiffer parts of your ears. Sharks are cartilaginous fishes which means they have a skeleton of cartilage. This skeleton is usually calcified but it is not true bone. The fins of a shark contain cartilaginous rodlike supports called ceratotrichia. Cartilaginous fishes are composed of two groups: (1) sharks and rays (Subclass Elasmobranchi) and (2) chimaeras (Subclass Holocephali)

      Read more: http://wiki.answers.com/Q/Do_sharks_have_bones#ixzz1y91KoUqt

    • Photo: Austin Elliott

      Austin Elliott answered on 18 Jun 2012:

      Cartiliaginous fish (of which sharks are one group) are very ‘ancient’ in evolutionary terms – they likely ‘branched off’ from the line that leads to bony fish (and ultimately to mammals) about 450 million years ago. Wikipedia has a kind of ‘tree of evolution’ here for all the chordates (animals with some kind of spinal cord-type structure).

      Talking of bony fish, the layout of the human skeleton has a lot more in common with the fish layout then people often think! There is a really cool science book called Your Inner FIsh about this – might be worth asking your teacher if they’ve heard of it.

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