Glycerol helps plump up a megamouth shark

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Another exhibit at the Fremantle Maritime Museum in Western Australia was this megamouth shark. I know it’s a terrible photo but it is what it is! The megamouth shark (Megachasma pelagios) is a deepwater shark rarely seen by humans. It is one of only three remaining filter-feeding sharks, the others being the whale shark and basking shark. It was only discovered in 1976. It has a large head with rubbery lips and swims with its enormous mouth wide open. It filters the water for plankton and jellyfish. This is a male and like other male sharks and rays have a pair of ‘claspers’ under their bodies. These are used to deliver sperm to females during mating. When not needed, the claspers lie flat against the body. Only one clasper is used at a time. What is interesting is that the creature was originally preserved in formalin and then stored in ethanol in a below ground site at the museum in Perth. Later it was removed from the ethanol and soaked in a glycerol solution for nearly three years. This has resulted in a more flexible, less shrivelled shark specimen. The shark has put on 115 kg and now weighs 484 kg. Who would have thought glycerol was fattening?