Do tiger shark pups attack and eat their siblings while still inside their mother's uterus?

It's true that tiger shark pups engage in intrauterine cannibalism - where they attack and eat their siblings while still inside their mother's uterus. This explains why tiger shark litters can start out very large, with over 80 eggs developing, but end up much smaller by birth, sometimes with fewer than 20 live pups born.

The reason they exhibit this cannibalistic behavior comes down to space constraints and nutrients. As the rapidly growing embryos cram into the limited space in the uteri horns, they start to jostle for position and resources. The biggest, strongest ones then turn on their smaller siblings, crushing and consuming them with their already sharp teeth in order to absorb the extra nutrients.

This acts as a sort of selection mechanism, ensuring that the strongest and fittest pups survive. The mother's body can also reabsorb some of the lost nutritional resources. Additionally, having fewer pups born may ultimately improve the chances of survival for those that make it.

So while it seems quite shocking, the tiger shark's internally violent beginnings actually confer certain advantages in ensuring healthy offspring. Their innate aggression starts early in the womb! It's part of why tiger sharks have persisted as apex predators - they come out fighting, literally eating each other, from the very start. 🦈👊