DIVE LOG Australasia

Mating scars of a female Grey Nurse shark

LIVE BIRTH IS TERMED VIVAPOROUS. All the other 60% of sharks give birth to live young. That is, babies are born from the mother alive. There are four types of live birth. OVOVIVAPOROUS - 60% LIVE BIRTH FROM AN EGG Tiger sharks for example, lay eggs which are retained within the two uteri. The foetus grows over a period of about sixteen months. At first, it gets all of its nourishment from the egg yolk.

In the case of the Tiger shark, females are bulkier and far more powerful than males. She is a magnificent display of power! She rules in her world! Whatever she does in the reproductive process is in no way an act of submission to the males and she is in control of her biology. No male could match the power of a female adult tiger shark! The apparently violent mating process that sharks display may be just that. Our superficial judgements do not reflect on what is really happening.

This female Silver Tip whaler from Beqa Lagoon is close to reaching maturity and her first reproductive cycle.

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DIVE LOG Australasia #408 - October ‘24