 A steady diet of sea urchins may stain the teeth of this shark pinkish purple.The crested bullhead shark is also a major predator of the eggs of the Port Jackson shark, which are seasonally available and rich in nutrients.Individual sharks have been observed taking the egg capsules in their mouths and chewing on the tough casing, rupturing it and allowing the contents to be sucked out; egg capsules may also be swallowed whole.