Smallest and Lightest Animals
Number one is the black garden ant at about 1–2 mg (0.00004–0.00007 oz) (workers, approximate; queens are many times heavier), followed by the yellow fever mosquito at about 1–2.5 mg (under 0.0001 oz) and the housefly at about 10–20 mg (0.0004–0.0007 oz).
| # | Animal | Weight | Notes |
|---|---|---|---|
| 1 | Black Garden Ant Invertebrate |
about 1–2 mg (0.00004–0.00007 oz) | workers, approximate; queens are many times heavier |
| 2 | Yellow Fever Mosquito Invertebrate |
about 1–2.5 mg (under 0.0001 oz) | unfed adults, approximate; a female can roughly double or triple her weight with a blood meal |
| 3 | Housefly Invertebrate |
about 10–20 mg (0.0004–0.0007 oz) | adults; females are larger than males |
| 4 | Seven-Spot Ladybug Invertebrate |
roughly 30–45 mg (about 0.001 oz) | adults; approximate, varies with feeding and season |
| 5 | Western Honey Bee Invertebrate |
about 100 mg (0.004 oz) | workers; queens and drones weigh roughly twice as much |
| 6 | Common Wasp Invertebrate |
roughly 70–250 mg (0.002–0.009 oz) | approximate; workers are under about 100 mg, queens considerably heavier |
| 7 | Monarch Butterfly Invertebrate |
0.25–0.75 g (0.009–0.026 oz) | adults; about 0.5 g on average |
| 8 | Buff-Tailed Bumblebee Invertebrate |
0.1–0.9 g (0.004–0.03 oz) | approximate; workers about 0.1–0.35 g, queens about 0.6–0.9 g |
| 9 | Guppy Fish |
about 0.1–1 g (under 0.04 oz) | approximate; small males at the low end, large females at the top |
| 10 | Southern Black Widow Invertebrate |
about 1 g (0.035 oz) | adult females, approximate; males weigh only a small fraction of this |
| 11 | Emperor Dragonfly Invertebrate |
about 1 g (0.035 oz) | adults; approximate |
| 12 | Luna Moth Invertebrate |
roughly 1–2 g (0.04–0.07 oz) | adults; approximate, since adult weight is rarely measured and females full of eggs are heaviest |
| 13 | Asian Giant Hornet Invertebrate |
roughly 2–4 g (0.07–0.14 oz) | approximate; published weights are scarce and queens are the heaviest caste |
| 14 | Eastern Newt Amphibian |
about 2–4 g (0.07–0.14 oz) | approximate adult weight |
| 15 | European Mantis Invertebrate |
roughly 1–4 g (0.04–0.14 oz) | adults, approximate; egg-laden females are heaviest and males much lighter |
| 16 | Betta Fish Fish |
about 2–5 g (0.07–0.18 oz) | approximate adult weight; bettas are rarely weighed |
| 17 | Ruby-Throated Hummingbird Bird |
2–6 g (0.07–0.21 oz) | adults; about 3 g normally, up to 6 g when fattened for migration; females are slightly larger |
| 18 | Common Earthworm Invertebrate |
3–10 g (0.1–0.35 oz) | adults |
| 19 | Garden Snail Invertebrate |
7–15 g (0.25–0.5 oz) | adults, including the shell |
| 20 | Red-Eyed Tree Frog Amphibian |
6–15 g (0.2–0.5 oz) | adults; females are larger and heavier than males |
| 21 | Lined Seahorse Fish |
about 5–20 g (0.2–0.7 oz) | approximate adult weight; seahorses are rarely weighed |
| 22 | Ocellaris Clownfish Fish |
about 10–25 g (0.35–0.9 oz) | approximate adult weight; females are the largest fish in a group |
| 23 | Emperor Scorpion Invertebrate |
about 30 g (1.1 oz) | typical adult; pregnant females can be heavier |
| 24 | Golden Poison Frog Amphibian |
up to about 30 g (1 oz) | approximate adult weight; the largest of the poison dart frogs |
| 25 | House Mouse Mammal |
12–30 g (0.4–1.1 oz) | adults; pet and lab mice are often heavier |
About this ranking
The lightest animals in our database weigh a fraction of a gram. Nearly all are insects, whose external skeletons and passive breathing systems work best at very small sizes. The smallest vertebrates here are hummingbirds, small frogs and aquarium fish.
How it is ranked: Ranked by the upper end of the typical adult weight range, lightest first. The list covers the 214 animals in the AnimalStats database, not every species on Earth.
The top five in detail
1. Black Garden Ant — about 1–2 mg (0.00004–0.00007 oz)
A black garden ant worker weighs only about 1–2 mg, so it would take several hundred to weigh a single gram. Queens are many times heavier, particularly newly mated queens, which carry the fat and flight-muscle reserves they need to raise their first workers without feeding.
2. Yellow Fever Mosquito — about 1–2.5 mg (under 0.0001 oz)
A yellow fever mosquito weighs only about 1–2.5 mg, so it would take several hundred to weigh one gram. A female can take in more than her own body weight in blood during a single meal, then rests for a couple of days while she digests it and develops her eggs.
3. Housefly — about 10–20 mg (0.0004–0.0007 oz)
A housefly weighs about 10–20 mg, so it takes 50 to 100 flies to weigh a single gram. Females are larger and heavier than males. Adult size depends on how well the maggot fed: crowded or poorly nourished larvae produce noticeably smaller flies.
4. Seven-Spot Ladybug — roughly 30–45 mg (about 0.001 oz)
An adult seven-spot ladybug weighs roughly 30–45 mg, about a thousandth of an ounce. Weight swings with how well the beetle has been feeding, and adults put on fat reserves in late summer to carry them through as much as six months of winter dormancy without food.
5. Western Honey Bee — about 100 mg (0.004 oz)
A worker honey bee weighs about 100 mg (0.004 oz), or a tenth of a gram. Queens and drones weigh roughly twice that. A forager can carry a nectar load of around 40 mg, close to half of her own body weight, back to the hive.