What’s the biggest thing a blue whale can swallow?

a) A very large mushroom
b) A small family car
c) A grapefruit
d) A sailor

A grapefruit.
Quite interestingly, a blue whale’s throat is almost exactly the same diameter as its belly button
(which is about the size of a side plate), but a little smaller than its eardrum (which is more the size
of a dinner plate).

For eight months of the year, blue whales eat virtually nothing, but during the summer they feed
almost continuously, scooping up three tons of food a day. As you may remember from biology
lessons, their diet consists of tiny, pink, shrimp-like crustaceans called krill, which slip down a treat.
Krill come conveniently served in huge swarms that can weigh over 100,000 tons.
The word krill is Norwegian. It comes from the Dutch word kriel, meaning ‘small fry’ but now
also used to mean both pygmies and ‘small potatoes’. Krill sticks have been marketed with
reasonable success in Chile but krill mince was a bit of a disaster in Russia, Poland and South Africa
owing to dangerously high levels of fluoride. It came from the krill’s shells which were too small to
pick off individually before mincing.
The narrow gauge of a blue whale’s throat means it couldn’t have swallowed Jonah. The only
whale with a throat wide enough to swallow a person whole is the sperm whale and, once inside, the
intense acidity of the sperm whale’s stomach juices would make survival impossible. The celebrated
case of the ‘Modern Jonah’ in 1891, in which James Bartley claimed to have been swallowed by a
sperm whale and rescued by his crew mates fifteen hours later, has been nailed as a fraud.
Aside from its throat, everything else about the blue whale is big. At 32 m (105 feet) in length, it is
the largest creature that has ever lived – three times the size of the biggest dinosaur and equivalent in
weight to 2,700 people. Its tongue weighs more than an elephant; its heart is the size of a family car;
its stomach can hold more than a ton of food. It also makes the loudest noise of any individual animal:
a low frequency ‘hum’ that can be detected by other whales over 16,000 km (10,000 miles) away.