Getting a sense for large numbers

First the names:

Now a ladder of real things, one rung per power of 10:

• 10⁰: as of mid-2025 only two northern white rhinos are left in the world, both female, at the Ol Pejeta Conservancy in Kenya (2 × 10⁰);
• 10¹: the Hainan gibbon population was 42 in early 2024;
• 10²: just 242 kakapo alive;
• 10³: fewer than 3000 Komodo dragons, all in Indonesia.

• 10⁴: more than 17000 maned wolves, most in Brazil;
• 10⁵: around 4.15 lakh African elephants;
• 10⁶: 50 lakh American alligators;
• 10⁷: over 3.5 crore camels worldwide (India has only about 2.5 lakh) and around 5.8 crore horses, about half of them in America.

• 10⁸: more than 20 crore water buffaloes, most of them in Asia;
• 10⁹: around 1.3 arab starlings, and 8.2 arab people as of 2025.

• 10¹⁰: about 33 billion chickens alive at any moment;
• 10¹²: about 3 trillion trees;
• 10¹⁴: around 110 trillion mosquitoes, and 500 trillion Antarctic krill.

• 10¹⁵: about 1 quadrillion beetles, and about the same number of earthworms;
• 10¹⁶: around 20 quadrillion ants. Ants alone outweigh all wild birds and wild mammals put together.

• 10²¹: the number of grains of sand on all the beaches and deserts on Earth, enough, the book says, to give every ant 10 little sand castles;
• 10²³: about 2 × 10²³ stars in the observable universe;
• 10²⁵: about 2 × 10²⁵ drops of water on Earth.

Scientific notation is what lets you compare any of these. With about 8 × 10⁹ humans and 4 × 10⁵ African elephants, there are nearly 20,000 people for every elephant: a division you can do in your head only because both are written this way.