From CBC:

Scientists at UBC have discovered — by accident — a rorqual whale can take a gulp of water that’s bigger than its massive body, then bounce back to its normal shape.

The whale has nerves to its mouth and tongue that can stretch to double their normal length, then snap back without damage, said Wayne Vogl, a professor in the department of cellular and physiological sciences at UBC.

“The nerves that supply these remarkably expandable tissues in the floor of the mouth of rorqual whales … are very stretchy, they’re like bungee cords,”

It was a surprising discovery, as most vertebrate nerves are more of a fixed length, said Vogl.

Amazing what a little over 3.5 billion years of natural selection can do.