Refined symbiotic species, Environment and life

Question

Taking into account the answer by akaioi to my previous question (Would a human-like symbiotic pair of the same race be possible?).

Answer:

Is it okay if we turn it around a bit?

That is, have the Tank be the youngster, and the Jockey be the older one. Why? Well ... it makes more sense for the old one to be the clever one. Imagine a species which evolves in an environment poor in food except for certain periodic windfalls, like a salmon run which only comes every several years. Here's how it works:

The adult, stable form of the creature is the skinny one. It needs all its cunning to survive the lean years, and its smaller form requires less food. Shortly before the salmon come, the creature spawns. The younglings gorge on the plentiful food, and grow large, fast. They'll need all this extra mass, because they're not yet smart enough to hunt the other, more clever prey in the region. When the lean season comes, the youngsters go through a kind of "reverse molting" where, as they deplete their food reserves, they shed their outer layers to reveal a smaller armor shell. Eventually you're left with the adult-form creature.

So there are actually four forms, of which we only care about two:

• Newborns — too small to be ridden, they're busy eating salmon and getting fat

• Tanks — These are the adolescents; they're big, dumb, and just the right size to bear a Jockey

• Jockeys — These are the dangerous ones. Still vigorous, smart, nasty, and fast.

• Geezers — Jockeys eventually get too old to ride into battle. So they retire, sit on the porch, and tell lies to the wide-eyed Tanks

My comment:

I like this as it could help for the development of their civilisation, when the period of large amounts of food come it’s possible for the tribe/group to go to battle with others in an attempt to gain an advantage or surplus for the harder times to come, so all the tribes will do this and then return to their homelands and as the food runs out the warring season will end with few attempts on others resources apart from maybe the more cunning of geezers/ jockeys.

Also with the old being smarter trades and such could develop as knowledge can be passed on so the elder geezers would be the most knowledgeable fighters and crafters using the brutes for manual labour or even guiding a jockey-brute pair to teach them. The geezers could even become unsuitable by for jockeying having another quick growth spurt one good season and then deteriorating from there so that they are strong enough for a while to carry out trades and be also be leaders. (https://i.sstatic.net/tAGwe.jpg)

Question:

My question for development on this idea is what kind of large food event could take place in the arid desert conditions that I described, somewhat similar to the deserts of Mexico.

Maybe their staple diet for the low periods could be a cactus type plant surviving on the heavy rainfall of the periodic event?

Another thing is what kind of culture may develop for this race due to what I have described, especially with the warring seasons at the end of the food surplus.

Thanks to akaioi for the great idea that I’ve chosen to run with.

Answer 1

An elliptical orbit, taking the planet from one extreme of habitability to the other over the course of a year, could provide the conditions for deserts and make it a planet-wide phenomenon affecting numerous types of food, and something that can't simply be avoided through migration.

An example of this sort of orbit can be found with Proxima b, in Alpha Centauri, a potentially habitable exoplanet:

At perigee (the point in the orbit closest to the sun, here labelled P) the planet is half the distance – and at the inner edge of the habitable zone – of apogee (the point furthest from the sun; A).

You will need to delve into orbital mechanics to get the exact distances and conditions right for your planet, given its dimensions and the type of star it orbits, but a long enough orbital period (longer than an Earth year) should produce the environmental conditions necessary to evolve such a species.

Answer 2

There are many examples of life forms that have adapted to harsh desert life where rain is rare. Animals might go into a form of hibernation, to only become active when it rains, while plants will release seeds which will only germinate when the weather conditions are right. Due to the fact that rainy times are usually extremely short-lived in deserts, such fauna and flora are adapted to go from zero to hero very quickly, and to do their living while the going is good and to go back into hibernation or die (depending on their life-cycle) very quickly. The Karoo region is a very good example of this though I am not able to find a page describing the natural cycle there clearly.

Such conditions would allow the young to gorge on the sudden abundance of food for a very short period of time.

Couple that with unusual weather conditions being needed to actually bring the rain, or to bring enough for the explosion of life required for your story, such as El Niño. You might have rare annual rainfall that is basically just enough to keep your population going for another year, with these heavy rains occurring only every so often.

If you want to localize your largesse, have the rain fall outside the desert and cause the flooding of a usually dry riverbed. Overnight, the river springs into being and dormant fish, amphibians and plants are suddenly crowding the river and its banks. Within a few days, the river's flow decreases down to a trickle and then dries up completely, taking with it the source of food.

Answer 3

You've sketched out a cultural symbiosis. We do that now as people. In many primitive cultures elders are the village 'library' They are the ones that remember 50 years ago during the famine we lived on lake slugs. But even since, we often have households with 3 generations. The current mix is that the grandparents take care of the kids, while the parents are at work.

Niven created the Grendels in "Legacy of Heorot" Young grendels are aquatic and are herbivores. Adult grendels eat young ones. The presence of an adult grendel keeps a hormone in the water that inhibits the transformation from the aquatic form to the adult form. The adults are territorial. Niven took his idea from a zoologist who told him about a frog in Africa that had nasty habits.

The grendels were obligate carnivors.

You can easily file the serial numbers off this, and recycle.

Picture a cross between Grendels and the world described by Swift's "A Modest Proposal"

Suppose that your people had children that were non-sapient herbivores. As long as they got a diet of the right plants they had the habits and IQ of sheep.

Periodically you butcher one of the kids for meat.

Grandfather has died of old age. You remove one of the kids from the pasture, and keep him in the barn. Initially there is a struggle, as the kid tries to regain access to food. Then he goes into a coma -- pupates if you will -- and regains consciousness as a small adult, having only vague dreams of his time as a sheep. It takes several years to educate him to the point where he takes his place in society.

If you want a disturbing variation, all the sheep are female and all the adults are male. Otherwise your females have a couple of litters of sheeplets a year. (Would take that to have a constant food supply)