Sharks pups survive on 'super livers'

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Sharks pups survive on 'super livers'

October 13, 2009 - 01:31
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Marine biologists have discovered shark pups are born with enlarged 'super livers' that act as a food source during the first few months of life.

Juvenille dusky shark

While the use of the liver as an energy store and for buoyancy is well documented in adult sharks, this study provides the first evidence of a decline in liver mass of newborn sharks, from 20% of body weight at birth to 6% when they start to feed themselves.

The research by a Bangor University-led international team of researchers shows that, during the critical period after birth, shark pups lose weight by consuming their liver reserves and that this weight loss is not necessarily an indicaton that the sharks are in a poor nutritional state, as has been previously thought.

"It is likely that the liver reserves enable the newborn sharks to acclimatize themselves to their environment and to develop their foraging skills" says lead researcher Nigel Hussey, "We know that large sharks use their livers as an energy store, but we had no idea that the mother provisions her young with additional liver reserves to enhance their survival."

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