--- title: "Emperor Dragonfly (Anax imperator) | AnimalTracks.wiki" description: "A big dragonfly whose larva fires a hooked mouthpart at prey, too fast for a water flea to escape." image: "https://animaltracks.wiki/images/animals/emperor-dragonfly-1.webp" published: "2026-09-29" updated: "2026-09-29" --- # Emperor Dragonfly (*Anax imperator*) > **Status**: Checked against 9 sources, listed under Sources below. > **Tagline**: A big dragonfly whose larva fires a hooked mouthpart at prey, too fast for a water flea to escape. > **Soundtrack Vibe**: Breakcore & Chaotic Drill // Venetian Snares, "Szamár Madár" > **Soundtrack Links**: [Spotify](https://open.spotify.com/track/6xqX8CidMDQ7eOLVlRiDgg) > **Vibe Match**: An Anax larva's labial mask shoots out in 25 to 40 milliseconds, and in lab tests the water fleas it struck had no time to escape. Venetian Snares chops drum breaks into hits milliseconds apart and fires them over the slow strings of Szamár Madár. ## Biological Superpowers & Stats - **Taxonomy**: *Anax imperator* - **Danger Level**: Low - **Conservation Status**: Least Concern ([IUCN Red List](https://doi.org/10.2305/iucn.uk.2024-1.rlts.t59812a208815239.en)) - **Superpower**: A larva with a labial mask, a hooked mouthpart that shoots out at prey - **Habitat**: Mainly large, weedy ponds, lakes, canals and slow streams across most of Europe, eastern Asia and much of Africa - **Diet**: Flying insects, large butterflies and other dragonflies; larvae take tadpoles and small fish - **Tags**: insect, flying, predator, carnivore, freshwater ## Natural History & Behavior ## A mouthpart that fires The emperor dragonfly, *Anax imperator*, starts life underwater. The young form, called a larva, is a hunter with an odd weapon. Dragonfly larvae catch prey by shooting out a labial mask, a mouthpart with movable hooks. Scientists call this kind of strike ballistic, like the tongue of a chameleon or a frog. > **Too fast to dodge** In lab tests, emperor larvae struck at 0.03 to 0.25 metres per second, more than 10 times faster than the water fleas they hunted could swim. The prey had no time to escape. Whether it caught them depended mainly on aim: about 40% of mistakes fell short of the target and about 60% aimed above or below it. An earlier study of *Anax* larvae, the emperor's genus, timed the mask at 25 to 40 milliseconds to extend fully. The larva is as voracious as the adult, and the Sussex Wildlife Trust says it will gorge on anything smaller than itself, tadpoles and small fish included. ## Big, but about a gram It is Britain's bulkiest dragonfly: an adult is about 78 mm long with a wingspan of about 10.5 cm. In a study in Normandy, France, mature females averaged 1.26 g and mature males 0.97 g. The larva reaches 45 to 56 mm. An adult may live for a couple of months or more, but the Sussex Wildlife Trust says it spends around ten times longer underwater as a larva. ## King of the pond Male emperors are very territorial. They patrol the water's edge and chase off intruders, and the Sussex Wildlife Trust describes them clashing with other dragonflies in the air. Emperors rarely settle, even eating prey in flight. Their menu includes large butterflies and other dragonflies. Adults have biting-chewing mouthparts. The female lays her eggs alone, in floating pondweed. ## Where it lives The emperor is widespread across the Old World, in all types of standing and slow-running fresh water. It is found throughout most of Europe and eastern Asia and is common in much of Africa. In Britain it lives in Wales and most of England, and it has been recorded in Scotland since 2003. The IUCN Red List rates it Least Concern. ## Frequently Asked Questions ### How long does an emperor dragonfly stay a larva? One or two years. Its eggs hatch after about three weeks, and the larva that comes out grows in the water until it emerges, during the night, as a winged adult. *(Source: [First Nature]())* ### How do you tell a male emperor from a female? Both have an apple-green thorax and a dark line down the abdomen. The male's abdomen is blue and the female's is usually green, though hers is occasionally blue. *(Source: [British Dragonfly Society]())* ### How does the larva see underwater? In fresh water, light is often partly polarized, meaning its waves vibrate mostly in one direction. In lab tests the larvae tracked a moving striped pattern better through such light, as if the pattern's contrast had been raised by 8%. *(Source: [Sharkey, Partridge & Roberts 2015]())* ### Has the emperor dragonfly moved north? Yes. It was one of the first dragonflies whose recent shift northward was noticed and put down to climate change. It was first recorded in Sweden in 2002, and one genetics paper reports that it crossed 970 km northward through Scandinavia in only 11 years. *(Source: [Herzog et al. 2016]())* ## Sources 1. [Vinko et al. (2024). Anax imperator. The IUCN Red List of Threatened Species 2024: e.T59812A208815239.]() 2. [Quenta Herrera et al. (2018). Temperature effects on ballistic prey capture by a dragonfly larva. Ecology and Evolution.]() 3. [Minot, Le Gall & Huste (2019). Biometry of the large dragonfly Anax imperator (Odonata: Aeshnidae): A study of traits from larval development to adults. European Journal of Entomology.]() 4. [Sharkey, Partridge & Roberts (2015). Polarization sensitivity as a visual contrast enhancer in the Emperor dragonfly larva, Anax imperator (Leach, 1815). Journal of Experimental Biology.]() 5. [Herzog et al. (2016). The complete mitochondrial genome of the emperor dragonfly Anax imperator LEACH, 1815 (Odonata : Aeshnidae) via NGS sequencing. Mitochondrial DNA Part B.]() 6. [Josten, Gorb & Büsse (2022). The mouthparts of the adult dragonfly Anax imperator (Insecta: Odonata), functional morphology and feeding kinematics. Journal of Morphology.]() 7. [Emperor Dragonfly. British Dragonfly Society.]() 8. [Duncan. Species of the day: Emperor Dragonfly. Sussex Wildlife Trust.]() 9. [Anax imperator - Emperor dragonfly. First Nature.]() *Published September 29, 2026. 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