My creature looks like a Psittacosaurus, with spikes all around its body, it hisses and uses its tail whip as a first. As last resort it will squirt an aimed stream of blood from its eyes toward its predator.

The blood only affects mammals (including humans) because it contains Capsaicin in high concentration (a compound that is found in chilli peppers)

My questions is:

Where can my creature get this Capsaicin, can it create its own or it has to get from a source (like its main food source that contains this subtance)? also how many times can my creature be able to squirt its blood to its attackers?

  • $\begingroup$ You know, the horned lizard can affect many predators (including mammals) even without that, simply because in our world you don't usually expect anything to squirt blood in your face from its eyes (though it does possess substances noxious to dogs and wolves). $\endgroup$ May 29, 2020 at 12:11
  • $\begingroup$ Eyelid is a no no, eyelash maybe to prevent dirt from clotting ;D $\endgroup$
    – user6760
    May 29, 2020 at 12:48

2 Answers 2


Both ways are possible: it can produce the molecule via endogenous processes and concentrate it in the blood or in the squirting glands, or it can intake it via alimentation.

Both processes happen in nature, so they are plausible.

How many time can your creature squirt its capsaicin doped blood it's up to you as designer, but I don't think it can spray it like it was a room deodorant.

Producing or harvesting the molecule and storing it has a certain energetic cost. Look at the skunks:

Skunks are reluctant to use this weapon, as they carry just enough of the chemical for five or six uses – about 15 cc – and require some ten days to produce another supply.

Moreover in your case your animal is spraying its own blood. So it can't bleed itself to death!

  • $\begingroup$ ok let say it produces this Capsaicin by itself and doesn't need to get it from a resource (like chilli peppers), how can it do that? $\endgroup$ May 30, 2020 at 7:46

It gets them through its food

The blood of IRL horned lizards is so noxious to their would-be predators because it contains high levels of formic acid, which they get from eating ants (especially harvester ants). The lizards don't produce the chemicals that make their blood a useful defense weapon themselves. This is common to a lot of reptiles and amphibians with defensive chemicals.

Therefore, the best way for your reptile to have capsacin in the blood that it sprays at its predators would be for it to include a lot of chile peppers in its diet, or an analogous plant that uses capsaicin as a defense mechanism. Capsaicin would probably be an easier compound to use for defense than formic acid in reptiles, as birds and reptiles are unaffected by capsaicin and only mammals are affected by it, whereas formic acid can be harmful to anything.


You must log in to answer this question.

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