Odds of being reborn as each animal
How many of each animal are alive at once, the source for every number, and your odds if one of them is drawn at random by head count.
| Animal | Alive now | Your odds | Rarity |
|---|---|---|---|
| Copepod | 1.3 × 10²¹* | 1 / 1.3 | Common |
| Soil nematode | 4.4 × 10²⁰ | 1 / 4 | Common |
| Insect | 1 × 10¹⁹* | 1 / 175 | Uncommon |
| Ant | 2 × 10¹⁶ | 1 / 87.5 thousand | Rare |
| Antarctic krill | 3.8 × 10¹⁴* | 1 / 4.6 million | Rare |
| Honey bee | 2 trillion* | 1 / 875 million | Rare |
| Fish | 1.3 × 10¹³* | 1 / 134.6 million | Rare |
| Wild bird | 48.4 billion | 1 / 36.2 billion | Epic |
| Bat | 56 billion | 1 / 31.3 billion | Epic |
| Chicken | 26 billion | 1 / 67.3 billion | Epic |
| Wild rodent | 26 billion | 1 / 67.3 billion | Epic |
| Human | 8.2 billion | 1 / 213.4 billion | Epic |
| House sparrow | 1.6 billion | 1 / 1.1 trillion | Legendary |
| Cow | 1.5 billion | 1 / 1.2 trillion | Legendary |
| Dog | 900 million* | 1 / 1.9 trillion | Legendary |
| Elephant | 465 thousand | 1 / 3.8 × 10¹⁵ | Legendary |
| Blue whale | 10 thousand* | 1 / 1.8 × 10¹⁷ | Legendary |
| Giant panda | 1.9 thousand | 1 / 9.4 × 10¹⁷ | Legendary |
* order of magnitude only. Legendary means rarer than one in a trillion.
Odds by pool
Any animal (true odds)
🧑 1 / 213.4 billion
Mammals & birds only
🧑 1 / 20.6
Any animal (true odds)
🐼 1 / 9.4 × 10¹⁷
How we count
We take the best published estimate of how many individuals of each group are alive at a time. Where only a total weight is published (krill, ocean fish), we divide it by a typical body weight and mark the result as an order of magnitude.
Your odds are that group’s count divided by the total for the pool you chose. Groups are not exhaustive: mites, springtails, worms and many marine animals have no reliable global count, so they are left out rather than guessed.
People: UN World Population Prospects 2024. Countries in the human life: births, life expectancy and sex ratio from UN WPP 2024; child mortality, schooling, internet use, urban share, poverty and income from Gapminder (UN IGME, World Bank, IHME).
Sources
- Copepod (1.3 × 10²¹, order of magnitude only): Widely cited order-of-magnitude estimate for the world’s copepods (~1.3 × 10²¹)
- Soil nematode (4.4 × 10²⁰): van den Hoogen et al. 2019, “Soil nematode abundance and functional group composition at a global scale”, Nature 572
- Insect (1 × 10¹⁹, order of magnitude only): Smithsonian Institution estimate: about 10 quintillion (10¹⁹) insects alive at any time
- Ant (2 × 10¹⁶): Schultheiss et al. 2022, “The abundance, biomass, and distribution of ants on Earth”, PNAS 119
- Antarctic krill (3.8 × 10¹⁴, order of magnitude only): Antarctic krill biomass of ~379 million tonnes (Atkinson et al. 2009, Marine Ecology Progress Series 362) at roughly 1 g each
- Honey bee (2 trillion, order of magnitude only): About 100 million managed beehives (FAOSTAT) at roughly 20,000 bees each
- Fish (1.3 × 10¹³, order of magnitude only): Extrapolated from ocean fish biomass estimates of 0.8–2 billion tonnes; only known to an order of magnitude
- Wild bird (48.4 billion): Callaghan et al. 2021, “Global abundance estimates for 9,700 bird species”, PNAS 118 (about 50 billion wild birds, sparrows counted separately)
- Bat (56 billion): Greenspoon et al. 2023, “The global biomass of wild mammals”, PNAS 120 (about 56 billion bats)
- Chicken (26 billion): FAOSTAT live animals: about 26 billion chickens (2022)
- Wild rodent (26 billion): Greenspoon et al. 2023, PNAS 120 (about 25–26 billion wild rodents)
- Human (8.2 billion): UN World Population Prospects 2024 (about 8.2 billion people)
- House sparrow (1.6 billion): Callaghan et al. 2021, PNAS 118: the house sparrow is the most abundant wild bird (~1.6 billion)
- Cow (1.5 billion): FAOSTAT live animals: about 1.5 billion cattle (2022)
- Dog (900 million, order of magnitude only): Commonly cited estimate of 700 million–1 billion dogs, most of them free-roaming (Gompper 2014, Free-Ranging Dogs and Wildlife Conservation)
- Elephant (465 thousand): IUCN African Elephant Status Report 2016 (~415,000) plus Asian elephants (~50,000, IUCN Red List)
- Blue whale (10 thousand, order of magnitude only): IUCN Red List: 5,000–15,000 mature blue whales
- Giant panda (1.9 thousand): China’s fourth national giant panda survey (2015): 1,864 wild pandas