Effect of two moons on wildlife
So given an inconceivably Earth-like planet with two moons in slightly differing orbits, how would the changed tidal system affect the wildlife? Specifically,
- What general type of marine wildlife would be affected by the tidal system (and how)?
- Would the currents shift?
- Would this affect migratory wildlife (and how)?
(edit) Regarding the [duplicate] tag, this question is not about the effect on multiple moons on the tides (as the linked "same" questions are) but on the way said tides would affect the wildlife, which is not answered in the aforementioned questions.
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1 answer
Obviously you need stable orbits long enough for evolutionary forces to take effect (millions of years), but clearly that could be possible with a large moon and some smaller moons; to emphasize the difference it makes in tidal patterns. That said, always presume the wildlife will adapt to take advantage, both offensive and defensive advantages. So you could for example have behavior changes specific to the overall super-system periodicity: Nights of bright light are for hunting the nocturnal animals, but they know this and avoid the bright nights, but that makes them very hungry on the following night, and the hunters come out in stronger force then. Or, there are periodic but rare dark nights; maybe only one a year, and many prey animals adapt to mate on this one dark night: Because it is the safest night for them to be at their most vulnerable. Interestingly, that also makes every offspring exactly the same age, and creates a cyclic pattern for hunters of (in human terms) infants, children, young adults and adults for their growth cycle: e.g. If it is April, the gazelle are giving birth; all of them. (Note because of our cold-to-warm seasons, we have a similar pattern in earth wildlife; almost none are born in the dead of winter.)
Although there are certain evolutionary "arms races" in which both sides reach some pinnacle of performance (cheetahs and gazelles), for the most part evolutionary adaptations reach some logical dead end due to an external circumstance that cannot be avoided. The owl is adapted to hunt small mammals at night; large eyes, silent flight, incredibly sensitive hearing. The mice it hunts have no evolutionary answer, other than a high rate of offspring. They haven't become any stealthier, their eyesight or hearing hasn't gotten any better to detect the owls, the day is still more dangerous than the night.
Instead of trying to work out your actual orbits and masses of multiple moons, just choose some interesting plausible features. Perhaps they regularly eclipse each other and pull tide together, perhaps they are sometimes opposite and there is no tide at all. If they are together on one side of the planet, there are no moons on the other side, and tide is exceptionally low, maybe the night is exceptionally dark. Do any of these present opportunity or disaster for wildlife? Does it affect the plant life or sea life and because of that change feeding patterns for the land-based wildlife? Can something take advantage of the fact that double-low-tide exposes reefs that are usually under water? Does double-high-tide force some prey animals to retreat and create a feeding frenzy?
The multiple moons scenario isn't about accurate algebra; it's about making a plausible story line due to the effects of multiple moons.
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