In my fictional world there are small organisms the size of a dog or smaller,some have the shape of mini-volcanoes, while some are stuck between rocks, they don't move and live in both sea and land.

This organism doesn't have natural predators as not being edible, it's as hard as rock and isn't killed by the digestive system of any animal.

However it releases a waste product, it's a red liquid similar to blood and some animals feed on it, if they find one while it releases it's waste product,some other colonial organisms farm them just like ants farm mushrooms on earth.

If animals feed on it, then it might be nutritious and contain minerals or other things... so what reasons does this blood fountain have to give up this nutritious liquid?


4 Answers 4


Warning: This answer is slightly mature, but is done in a strictly biologically speaking context.

The male creatures could release some version of fertilization, and use the animals that drink the liquid to spread the fertilization on the slopes of the females (as excrement), and the females absorb the fertilization for offspring.

Similarly, the females could produce very, very small fertilized eggs that the animals would likewise spread through excrement.

Both aspects are very similar to how many plants spread via berries and animals spreading the berries' seeds, and also draws some parallels with bees spreading pollen.

  • 5
    $\begingroup$ So are all fruit also “slightly mature”? $\endgroup$
    – JDługosz
    Aug 19, 2016 at 22:16
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    $\begingroup$ @JDługosz Well the answer boils down to (for the first part) animals eating other animals' semen. I guess I wanted a quick warning so people weren't shocked when reading. $\endgroup$
    – Ranger
    Aug 19, 2016 at 22:40
  • $\begingroup$ @NexTerren why tho? bees do that all day long. $\endgroup$
    – Tacroy
    Aug 20, 2016 at 1:45
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    $\begingroup$ @Tacroy ...Because we, as humans, tend to see pollen different than animal semen? Listen it was honestly a shock warning and that's it for anyone who might be shocked. Don't look into it too deep. $\endgroup$
    – Ranger
    Aug 20, 2016 at 1:46
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    $\begingroup$ @JDługosz Well yeah, the edible part of fruit is an expanded ovary wall. Plant sex is pretty normalized in our culture, though. $\endgroup$ Aug 20, 2016 at 2:41

Continuing with the "ant" example you mention:

I believe you're reffering to the Leaf-cutter ant; These ants basically "farm" a type of fungus for food. This is a type of mutualism, as both species depend on the other to perform some function (protection, nutrition, etc.).

We see a similar function with Ants and Aphids. Aphids produce a sweet nectar like substance that the ants eat, in turn the ants provide protection. In some cases the ants actually shelter Aphid eggs in their colonies over the winter; come spring the ants bring eggs out to plants that the aphids will feed on.

In a similar way your blood fountains could simply be in a mutualistic relationship with another organism. Perhaps being immobile they need swift creatures to bring them prey that they digest, then they excrete the parts that they don't need for nutrition that their swift companions DO need for survival.

Perhaps what the Blood fountains digest is normally "junk" by other creatures standards? Something like a clam's actual Shell? The waste product may just be something useful to other creatures like carbohydrates or fat; but not necessary for your Blood Fountain's biology.


My first thought was salt, for something a creature might want to get rid of, that others still might want - and you wanted it red, so maybe iron, or other hard minerals. Partly inspired by the threads on a creature's fear of water caused by osmosis, to be fair.

It looks like the creature is living in fairly mineral rich environments - in between rocks, near the sea, and they don't move so must have some way of regulating themselves of minerals present in high concentration. Most creatures can tolerate a fairly narrow band of salinity, because osmosis will lead to too much or too little water pressure. Other minerals are also helpful in reasonable amounts, but dangerous if the amounts get too high.

If the creatures are living in areas where the mineral/salt content may vary, since they can't move they have to have some way of dealing with the excess - in this case, instead of regularly getting rid of them, it is expelled once it builds up to a certain point. Since the hard minerals are still good, other animals may benefit from them - which has an additional bonus of tending to carry them away from an area where the concentration is too high for your critter.

If the products are mixed with the creature's usual waste, that might be a problem for other animals using it, since it would also have the toxins and byproducts the critter needs to rid itself of and which other animals won't want. It may have evolved to expel different types of wastes separately, perhaps the red is specifically beneficial because it contains mainly concentrations of minerals and salts, and there is some other waste product(s) that contains the toxins, that animals can avoid. Of course, this adaption only makes sense if the creature benefited from the animals' presence somehow, maybe the increased traffic means more manure to grow the plants it eats, or attracts whatever its prey is.


Other than the reasons mentioned by others, the liquid could attract animals that the organism then kills. The most likely case is that the blood itself causes the death of the animal or atleast causes it to fall unconscious. Though if it did this regularly it would be easily avoided by the smarter animals.


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