00:00 Who, or what, is, in your opinion, the most efficient hunter on the planet?
00:05 No, it's not lions, nor sharks, nor eagles, nor wolves.
00:09 Sharp teeth, a powerful roar, huge claws and a terrifying appearance
00:14 don't automatically make an animal a good hunter.
00:18 The main indicator of the efficiency of an animal
00:20 lies in its ability to succeed in catching a prey.
00:24 For example, lions can catch their meal only once in four,
00:28 while sharks only succeed in half of their attacks.
00:32 Wolves and eagles, on the other hand,
00:34 must make considerable efforts to ensure their meal.
00:38 However, there is a creature that systematically succeeds in catching its prey,
00:43 the dragonfly.
00:45 More than 90% of these hunting attempts are crowned with success.
00:49 If dragonflies were the size of giant griffins,
00:52 they would undoubtedly dominate the top of the food chain of our planet.
00:56 Moreover, these insects were even larger in the past.
01:01 But we'll talk about it later.
01:03 For now, let's focus on what makes dragonflies so efficient.
01:08 Two of the main factors contributing to the success of dragonflies when they hunt
01:12 reside in their speed and their manoeuvrability.
01:16 Dragonflies have the wings among the most efficient in the world.
01:19 They can glide in the air, change direction in a few seconds,
01:23 be stopped, fly backwards and even turn in a circle.
01:27 For comparison, birds, on their side, take about a second or more to take off.
01:32 Their flight is certainly graceful, but it lacks manoeuvrability.
01:36 Birds are indeed unable to stop quickly or change direction easily.
01:42 Their movements are fluid but limited.
01:44 However, dragonflies have four wings, two at the front and two at the back,
01:49 and these wings can move independently from each other.
01:53 In just three wings, dragonflies can reach a speed of 50 km/h,
01:58 which is equivalent to the average speed of cars in the city.
02:02 In addition, the braking distance of dragonflies is very short.
02:06 If an ordinary car were to stop at the same speed, it would skid several meters.
02:11 However, a dragonfly is able to stop abruptly at any time,
02:15 with a braking distance almost non-existent.
02:18 Thanks to this remarkable talent, dragonflies rise, dive and perform 360-degree pirouettes,
02:26 which makes them unbeatable hunters to which nothing can escape.
02:30 Finally, just 10%.
02:32 Nevertheless, their super-efficient wings would not be enough
02:35 if they were not complemented by a brain that works wonderfully.
02:39 Almost all insects rely on their odors and touch to hunt.
02:43 Let's take the example of a spider on its web.
02:46 It detects all contact with delicate girls and determines the location of the prey thanks to vibrations.
02:53 Dragonflies, on the other hand, rely mainly on their exceptional sight.
02:58 They can focus on a target just like humans,
03:01 by totally abstracting from external distractions.
03:05 Imagine yourself in a large room with many TVs hanging on the wall,
03:09 each broadcasting a different film.
03:11 In the midst of this chaos, you spot your favorite comedy,
03:15 and you can focus on it while completely ignoring the sounds and images of other TVs.
03:21 A dragonfly has a similar ability.
03:24 If it observes a swarm of flying mosquitos in various directions,
03:28 it is able to focus on a single mosquito
03:31 and follow each of its movements.
03:34 The mosquito will not be able to hide in the crowd.
03:37 Oh oh!
03:38 The part that allows a dragonfly to fly resides in its chest.
03:42 Similar to the bone marrow, this center receives signals from the brain
03:46 and transmits them to various members of its body.
03:49 In addition, the dragonfly's brain is connected to its thorax.
03:53 When the insect focuses on a target,
03:56 16 neurons form a chain through which the signals pass from the brain to the wings.
04:01 This rapid communication guides the wings in their flight
04:04 and allows them to capture the target.
04:08 The dragonfly looks at the mosquito, then calculates the interception trajectory.
04:12 In case of problem, the dragonfly can adjust the movement of its wings during the flight.
04:17 Its eyes occupy most of its head and are made up of thousands of small lenses.
04:23 They can see at nearly 360 degrees,
04:27 and some species have a field of vision of about 12 meters.
04:31 This distance may seem small, but compared to that of a human being,
04:35 it is an excellent vision for its small size.
04:39 In addition, some dragonflies have an ultraviolet vision
04:43 that allows them to distinguish their environment very clearly
04:46 and to focus on the target while maintaining the viewing angle during the flight.
04:50 Even if it faces the wind or if the target changes position,
04:54 a dragonfly maintains the same angle on the prey
04:56 while adapting its wings to a new flight trajectory.
05:02 All these amazing abilities allow these insects to catch a prey in 95% of cases.
05:11 They attack mosquitos, night butterflies, butterflies, flies and even other dragonflies.
05:17 Their legs are strong and spiky, which allows them to firmly grip their prey.
05:22 However, these advantages do not make them the main predator in nature.
05:29 Dragonflies can become the prey of toads, birds, fish and even turtles.
05:35 As they mainly fly over swamps, lakes and ponds,
05:40 they are not always able to spot a predator climbing into the depths.
05:44 They can easily become the meal of a bird in flight or get caught in a spider web.
05:50 However, dragonflies would have made fewer enemies
05:53 if they were as big as 300 million years ago.
05:56 Before dinosaurs traveled the Earth, insects measuring 0.7 meters in diameter flew in the air.
06:04 They were known as griffons and looked like dragonflies the size of a horn.
06:10 A drawing of these monsters could easily disrupt your barbecue party.
06:15 Hmm, I think we're going to need a bigger fly mat.
06:20 During prehistory, the atmosphere contained 9% more oxygen.
06:25 Insects absorbed it through special respiratory tubes that functioned as an alternative to lungs.
06:32 The high oxygen saturation helped them grow for millions of years.
06:37 However, their heavy weight prevented them from maneuvering and flying as fast as today's insects.
06:43 Griffons were clumsy flying insects.
06:46 About 150 million years ago, I wasn't there at the time,
06:50 insects began to shrink in size.
06:53 It's interesting to note that the oxygen levels in the atmosphere hadn't changed.
06:58 But something seemed to influence the growth of insects.
07:02 Scientists are convinced that insects began to shrink when the great prehistoric birds appeared.
07:09 Giant dragonflies have become easy prey in the sky,
07:14 which has encouraged nature to reduce their size to increase their agility.
07:19 They have become smaller, but their flying skills have improved considerably.
07:24 Now let's look at another insect with exceptional flying skills.
07:28 The domestic fly.
07:30 This annoying insect roams around your room and disturbs your sleep.
07:35 You may have already wanted to crush it with a slipper or a newspaper.
07:40 But it's a real challenge,
07:42 because the attention and reaction speed of this fly are several times higher than yours.
07:46 Imagine two acrobats.
07:49 One performs acrobatics and bold jumps in a gym.
07:53 The other, underwater.
07:55 The underwater acrobat would move much slower,
07:58 with predictable movements and apparently heavier than the one in the gym.
08:03 Isn't it?
08:04 Well, against this annoying insect, you look like an underwater acrobat.
08:09 As fast as the blow you try to give for the fly,
08:13 your hand will move as fast as a balloon inflated and falling on the ground.
08:17 Not to mention that the fly sees better than you,
08:19 thanks to thousands of receivers that capture the light around it.
08:23 You contract your muscles and move your eyes to see something on the side.
08:28 But the fly doesn't need it.
08:30 It sees everything at the same time.
08:32 If you think you're getting close to a fly without it noticing you, you're wrong.
08:37 It sees everything and is ready for any attack.
08:40 Like a dragonfly, the fly can easily change speed and direction, slow down and accelerate.
08:47 It is even able to anticipate the trajectory of your hand.
08:51 When you shake a newspaper to crush it,
08:54 the fly calculates the impact point and its body immediately prepares for an evasion maneuver.
08:58 In a way, it can dodge the attack before you even hit it.
09:02 Can you imagine if flies and dragonflies increased their size
09:06 while maintaining their speed and their ability to react?
09:09 Humanity would be confronted with problems.
09:12 Let's say, size.
09:14 It is the case to say it.
09:16 And do you know why flies love you so much?
09:18 Because your body is a vast clearing where you can find free food all the time.
09:23 Starting with the sweat you secrete and which contains a lot of delicious snacks,
09:28 such as proteins, salts, carbohydrates and a lot of other chemical substances.
09:34 Flies love these things and at the same time have no real threat from the outside.
09:40 Of course, there are giant beings that slowly shake their big hands.
09:45 But is it a reason for them to give up the feast?
09:48 Of course not!
Comments