2019-02-01_Popular_Science

USUAL SUSPECTS

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16 SPRING 2019 • POPSCI.COM by Jillian Mock / illustration by Goran Factory

WHAT’S THE FASTEST ANIMAL ON EARTH? DEPENDS ON HOW YOU

define quickness. By simple miles per hour, classic mega-

fauna like cheetahs dominate the leaderboard. But if we

measure velocity by the body lengths an animal travels per

second, those quick cats have some competition. This race

of proportions allows contenders from all kingdoms to go for

gold. Here’s how a cross-section of critters achieves top speeds.

4. COPEPOD
   MIGHTY LEGS

Where there is water, there are

copepods serenely floating. In

times of crisis, the torpedo-

shaped 1-millimeter crustaceans

can accelerate to 500 body

lengths per second. Two kinds of

limbs—some vibrating oars for

swimming and some stronger legs

for jumping—allow the creature to

blast over 20 inches, perfect for

escaping a fish’s gaping jaws.

1. COMMON SQUID
   JET PROPULSION

This cephalopod shoots through

the ocean like a tentacled jet. It

sucks water into a chamber in its

8-inch-long cone-shaped body,

then contracts its muscles to push

the liquid through a narrow

funnel- shaped organ near its

head. The flow blasts in one direc-

tion, launching the adult squid’s

gelatinous form the opposite way

at 10 body lengths per second.

2. CHEETAH
   SPEEDING SPINES

Famous for sheer giddyup, these

spotted cats’ flexible spines give

their limbs a wide range of mo-

tion. The stretch maximizes stride

and allows acceleration from zero

to 60 mph in three seconds. Hind

legs dense with fast-twitch fibers—

a powerful type of muscle—

enable 70 mph bursts. But factor

in body size, and they fall behind:

23 lengths per second.

3. HUMMINGBIRD
   DIVE FOR LOVE

Hummingbirds pump their wings

in a figure eight so quickly that

humans see only a blur. To impress

the ladies, 4-inch-long male

Anna’s hummingbirds accelerate

faster than any other vertebrate

relative to body size—including

fighter pilots. Suitors fly at 385

body lengths per second during

their customary courtship dive, all

powered by outsize pecs.

BODY

LENGTHS

PER SECOND

Mite

192.

Cheetah^2

22.

Yellow garden

spider

14.

Common

squid^1

10

Gorilla

5.

Snowshoe

hare

35.

Copepod^4

500

Anna’s

hummingbird^3

385