Summer Most Heat Moon
The dragonfly came up in conversation yesterday because I saw one outside the window at Running Aces and remarked I’d read they hadn’t changed in 300,000,000 years. A remarkable fact to me and one I confirmed in some quick internet research this morning.
Tom then added that they were unique in their ability to vector their prey, that is, calculate the prey’s path and their own so they would intersect. All other apex predators chase their prey. Very interesting. (see video below)
A little more poking around found a few more interesting facts about the dragonfly, but I put the most remarkable one (to me) last.
1. The study of dragonflies, and sometimes damselflies, is called Odonatology. Dragonflies are referred to as Odonates.
2. About 5000 species of dragonflies and damselflies are known
3. Top speed for a dragonfly is between 30 and 60 km/h (19 to 38 m.p.h.)
4. A dragonfly needs warmth to fly and you will notice they will often land when
the sun goes behind a cloud.
5. Because of their compound eyes, dragonflies can see in many directions at once
6. Fact: They Calculate Velocity For A Perfect Kill
The dynamics of capturing an object in mid-air are staggeringly complex, so much so that it’s usually something that’s only done by animals with complex nervous systems, like seagulls, or humans. To intercept something moving with its own velocity, you have to be able to predict where it will be in the future. When researchers began studying dragonflies in 1999, they found that rather than “track” their prey—follow it through the air until they caught up with it—they would actually intercept it. In other words, dragonflies ensure a kill by flying to where their prey is going to be.
That indicates that dragonflies calculate three things during a hunt: the distance of their prey, the direction it’s moving, and the speed it’s flying. In the space of milliseconds, the dragonfly calculates its angle of approach and, like a horror movie monster, it’s already waiting while the hapless fly stumbles right into its clutches.
7. Most of a dragonfly’s life is spent in the naiad form beneath the water’s surface…They breathe through gills in their rectum, and can rapidly propel themselves by suddenly expelling water through the anus.[6