One heart, one billion beats

Small hearts race and large hearts idle, yet across mammals the lifetime total keeps landing in the same place. Each trace is a pulse line — denser spikes mean a faster heart — ending in the lifetime total.

Approximate lifetime beats — rate × lifespan. Line frequency mirrors resting pulse.

Field noteA shrew's heart hammers near 800 beats a minute and it lives about two years. A blue whale idles at a resting pulse you could count on one hand and lives past eighty. Multiply rate by lifespan and most mammals settle close to a billion beats. Humans are the odd ones out, pushed by modern medicine to roughly two and a half billion, well past the natural allowance.

Speed is relative

The fastest animal on Earth becomes a crawler the moment you measure it against its own body. Each dial reads body lengths travelled every second, not kilometres.

Field noteA cheetah covers about sixteen of its own body lengths every second. A dust-sized Californian mite manages more than three hundred, the fastest relative pace ever recorded on land. In plain kilometres the mite barely creeps, yet scaled to a human it would be sprinting faster than sound.

A life spent sleeping

Rest has little to do with body mass. Each ring is a full 24 hour day; the filled band is time spent asleep.

Field noteA koala can sleep twenty two hours a day while a giraffe of far greater bulk gets under two. Stranger still, dolphins and some seabirds rest one brain hemisphere at a time, and the great frigatebird sleeps while still in flight during weeks over open ocean.

The long wait

Carrying time runs from under two weeks to almost two years. Each dot sits on a shared scale from 0 to 660 days.

Field noteA Virginia opossum is pregnant for barely thirteen days, then finishes raising its young inside a pouch. An African elephant carries for close to twenty two months. The suspected record belongs to the deep-sea frilled shark, rumoured to gestate for over three years in the cold and the dark.

Small bodies, giant leaps

Measured against their own length, insects humble every athlete, and one heavyweight cannot leave the ground at all. Each arc traces a leap, height scaled to body lengths cleared.

Field noteA froghopper launches at accelerations near four hundred times gravity, and a flea clears roughly one hundred and fifty times its own length. A human manages about five. The elephant sits at the far end as the only land mammal that can never get all four feet off the ground at once.

A day, or five centuries

Lifespans span five orders of magnitude, so this spiral is wound to true linear scale: arc length from the centre is directly proportional to years lived, coiled so five centuries still fit on the page.

Field noteAn adult mayfly may live a single day. A Greenland shark can pass four hundred years, and an ocean quahog clam named Ming reached about five hundred and seven. The immortal jellyfish outlasts them all by reverting to an early life stage and beginning again, in principle without any end.

Louder than a whale

The loudest sounds in nature do not always come from the largest animals. Each burst of rings shows peak loudness in decibels — the wider the ripple, the louder the source.

Field noteA snapping shrimp no bigger than a thumb fires a collapsing bubble at more than two hundred decibels, briefly heating the water near the temperature of the sun's surface. That single click rivals a sperm whale and outguns every animal on land, including the howler monkey heard five kilometres away.

Eyes the size of dinner plates

Drawn to true scale, some eyes dwarf a human head. Each circle below is one eyeball, sized by its real diameter, resting on a shared baseline.

Field noteThe colossal squid carries eyes about twenty seven centimetres across, the largest of any animal. On land the ostrich wins, with an eyeball larger than its own brain. The tiny tarsier takes the relative crown, each eye as big as its brain and locked in place, so it swivels its whole head to look around.

The longest commutes

Distance travelled has nothing to do with body mass. Each flight path arcs higher the farther that animal migrates in a single year.

Field noteThe Arctic tern chases endless summer from pole to pole and back, up to ninety thousand kilometres a year. Over a thirty year life that is close to three round trips to the Moon. A humpback whale thousands of times heavier covers only a fraction of the same distance.

When blood runs blue

Red is common, not universal. The pigment that carries oxygen changes the colour, and the chemistry, of blood across the animal kingdom.

Field noteHorseshoe crabs and octopuses run on copper, which turns their blood blue and works better in cold, low-oxygen water. Some New Guinea skinks carry green blood loaded with a pigment that would poison a human. Antarctic icefish went furthest of all and dropped colour entirely, the only vertebrates alive with no red blood cells.