Whale-eating Sharks?

I’m giving my son a bath last night, and we’re cheerfully splashing and making a mess. As we play, we get to talking about stuff. Over the course of talking and playing, I ask him if he knows what the biggest animal ever is. He say “no”, so I tell him it’s the blue whale.

His eyes get big, but then his imagination kicks in and he starts telling me about the “blue shark whale”. This shark, he assures me, hunts and eats blue whales. It eats them up, and gets bigger and bigger until there’s nothing bigger in the whole world.

“Really?” I ask.

“It’s true,” he says, gravely. “It’s really, really true.”

No it’s not, but you have to love his imagination. So I decided to spend a little time looking up sharks. There is a blue shark (Prionace glauca), which is rumored to get up to 20 feet long – although males are generally 6-9 feet and females 7-10 feet.  So, not precisely the whale-eating shark of my son’s imagination.

There is also a whale shark (Rhincodon typus), which can grow up to around 40 feet in length (with unconfirmed reports of longer).  It’s a filter feeder, though, eating plankton and krill and unlucky small fish. A blue whale wouldn’t fit in it’s mouth, so it isn’t my son’s whale-eating shark either.

The megaladon (Carcharodon megaladon), a predatory shark that could grow up to 54 feet, could have fit the bill. Sadly(?), they died out no later than 2.6 million years ago (the Discovery channel notwithstanding).

Generally speaking, blue whales have almost no predators.  A pod of killer whales will attack them, but it’s rare for sharks large enough to threaten a blue whale to hunt in packs.  So I guess I’ll need to get my son to obsess on Orcas instead.