Normally, a pregnant female of any animal species consumes more food than the average for her species. A period of starvation for the mother can result in the birth of defective offspring or no birth at all.
Some species of sharks engage in a unique form of intrauterine cannibalism known as «oophagy.» The ovaries of these sharks contain many thousands of very small eggs. The first group of embryos to develop survives by feeding on the successive batches of eggs that the female continues to produce.
In the case of the bull shark, oophagy goes even further: Not content with the continuous supply of eggs, an embryo from the initial group attacks and devours its siblings that are still developing. As the female has two separate uterine chambers, the birth of at least two offspring is ensured since they cannot encounter each other. It could be said that this is one of the few cases in nature where an animal attacks and kills another even before being born.
Currently, the relationship between divers and sharks has changed significantly. Twenty years ago, we had to assure our students that they wouldn’t encounter sharks during the dive. Nowadays, if we don’t guarantee that they will see them, they are disappointed. Techniques developed over the years now allow divers from all over the world to participate in scheduled dives solely for the purpose of diving with sharks and being amazed by the majestic presence of these animals swimming freely.
«You cannot defend what you do not love, and you cannot love what you do not know.»