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In 1330–1353, a plague known as the Black Death
killed more than 75 million people worldwide. The
bacterium responsible was carried by fleas on rats.
Fleas breed so fast that, in just three weeks, a
single adult pair can populate your pet with a
thousand more fleas.
Flea eggs, laid on a host, hatch into legless larvae, which eat the dried blood in the poop of adult fleas.
Eggs and larvae may drop off a host at any time. The larva later pupates (develops inside a pupa), often
resting in a carpet for months until a host walks near. Then it suddenly springs out to jump onboard.
A flea can jump 30,000 times nonstop! It jumps by
flexing a pad of resilin (a highly elastic protein),
then releasing the energy through its legs.
Ever seen a flea going backward? Nope. Backward-
pointing bristles on its body help it to push
constantly—and rapidly—forward.
C
hampion
J
umpers
I don’t do
backward.
29,994, 29,995,
29,996 . . . phew . . .
Breakfast!
Where are
all those kids?
Fleas, eh?
Don’t they just
make you sick?
It’s dinner time!
