A hydra is a multi-headed beast usually depicted as a serpent in many mythologies. I suppose each head should have an independent brain and thus would each have a different wake/sleep cycle not unlike a dolphin (though the latter sleep with one hemisphere at a time to watch out for threats in the treacherous sea).

With that out of the way my question is how hydrae chase down bird flocks for food? Dolphins achieve this by teamwork, but hydrae are independent, so how do they hunt down bird flocks since endurance isn't their strength in the air and neither is running on rough surfaces?

N.B.: These hydrae weigh 100kg, are highly territorial and can fly at speeds of up to 65km/h.

  • 2
    $\begingroup$ But you've told us how it flies - fast. What's the question? $\endgroup$ Feb 3, 2021 at 3:33
  • $\begingroup$ @Tantalus'touch: look at the speed again this is barely catching up with the preys... and only briefly ;D $\endgroup$
    – user6760
    Feb 3, 2021 at 3:39
  • $\begingroup$ The sleep/wake cycle is a huge obstacle here. Is the hydra trying to fly with one head and neck flopping dreamily in the breeze, or does each head get woken up every time the collective goes to hunt? Also, would your world happen to have any fascist insects? Versimilitude and all. :) $\endgroup$ Feb 3, 2021 at 12:08
  • $\begingroup$ Multiple necks could create a unique additional control surface for the hydra. Squid have been observed to fan-out their tentacles during airborne flight to give additional lift. The necks could fan out like a canard wing. $\endgroup$
    – DWKraus
    Feb 4, 2021 at 1:19
  • $\begingroup$ This assumes that the heads have brains in them. The brain might be at the base of the necks. $\endgroup$
    – Monty Wild
    Feb 4, 2021 at 4:07

4 Answers 4


They dive from great heights

Your hydra spends all day flapping, flapping.... flapping. It gets high in the air. Then it soars for hours, heads blowing flaccidly about.

When it sees a flock far beneath it, it dives like a squidly peregrine falcon. Each head is on its own as it traverses the flock, grabbing a bird each.

The hydra is invulnerable of course and so makes no effort to slow down, hitting the ground at tremendous speed with a characteristic sound.

  • 3
    $\begingroup$ "hitting the ground at tremendous speed with a characteristic sound"....thank you. now of the rest of the day everything will smell like snorted coffee. $\endgroup$
    – PcMan
    Feb 3, 2021 at 6:09
  • 1
    $\begingroup$ If it waits until they're nesting, it could just hit the flock at tremendous speed with a characteristic sound... $\endgroup$ Feb 4, 2021 at 1:35

With tools

All that extra brain power should go towards developing tools to hunt. I'd expect a hydra to hunt using a bow an arrow - otherwise what have those heads been doing all these years?

They can harvest fibres from plants, spin them into thread, weave the thread into nets, and use those nets to hunt multiple birds at once.

Stretch a net between two trees, scatter some food scraps on one side of the net. Flock of birds lands to peck at the food. Hydra jumps out, scaring the entire flock into the net.


Wing buffeting air disruption:

Your hydra either sneaks or dives on the unsuspecting birds, then uses it's considerable size and wings to create sudden gusts of air that disrupt the flight of smaller flying creatures. This is most likely on the ground (knocking the birds over and preventing them from taking off to escape) but could, in theory, create so much turbulence as to disrupt the flight of birds mid-air. Tumbling birds desperately trying to take off or recover control are easy pickings for the multi-headed hydra that can come at an individual bird from multiple directions, essentially pack hunting without the pack.

  • $\begingroup$ nice disoriented birds make easy prey ;D $\endgroup$
    – user6760
    Feb 4, 2021 at 1:47

They pull the old Scylla maneuver

A hydra would be a terrible flying animal. They would by definition be front-heavy because of all their extra necks and heads (not to mention the large heart and lungs required to sustain said necks and heads), which would result in the animal being tipped forward while in flight and prone to be sent into a tailspin. Their body plans makes them not aerodynamic at all because the thickest area of the body is at their front, rather than the animal being in a torpedo or bird-like shape. On top of that all of the additional heads would be a liability when catching prey. The heads and necks moving every which way chasing prey would send the animal frequently off balance while in flight. At minimum it would require an extremely high degree of coordination, which would require huge brains with large flocculi per head, which becomes multiplicatively expensive for a hydra and kind of defeats the purpose of a hydra in the first place.

What flight would allow a hydra to do, on the other hand, is get the hydra into position where it can attack unsuspecting prey. Sort of like what Scylla did in The Odyssey. Fly up to a high rocky crag where you know flying prey like birds or bats or small dragons are passing by and use your head to snag some of them as they fly past. This is analogous to how long-necked predators in Earth's past, such as Tanystropheus and plesiosaurs, are thought to have caught prey. Being able to fly increases the number of positions an animal can take to ambush prey, especially ambushing from above. A hydra may be a terrible flyer from a comparative perspective, but it still should be able to at least get itself into the air and haul itself over to a good hunting perch.

A hydra would also have to have a high degree of correlation between its heads, and the heads would almost have to be linked somehow and not be fully separate organisms. The reasons for this can be seen in developmentally abnormal snakes that have two heads: when presented with food the two heads will fight with each other over who gets to eat despite the fact that the two have the same stomach, wasting time and energy. A fully coordinated hydra would be well-suited to using its heads to out-maneuver and corner small flying prey like bats and birds.

As a corollary, getting up high and then snagging birds and bats as they fly past in large numbers is exactly how snakes and centipedes hunt flying animals in real life, though none of them have multiple heads.


You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .