The rock is spherical. All arthropods are included. They have no time limit and are "programmed" to cooperate, but lack intelligence. While there is no time limit, the insects do this transportation in the most efficient way possible. (Assume the most efficient method you can think of.) While this question is about Finland -> South Africa specifically, this rock-transportation happens all the time from all across the world and has been happening for thousands of years, so all insects on the planet are not available to transport this one rock.

(This is a detail irrelevant to the specific question, but the rocks vary in size and are picked up from the brains of every animal that dies, and the rocks' journey to South Africa is SORT OF the insects bringing them to the afterlife.)

  • $\begingroup$ Can the participating insects communicate with each other? $\endgroup$ Jun 22, 2017 at 15:47
  • $\begingroup$ @AmbroseWinters Their transportation behavior (whatever it is) is programmed into them. Assume their communication is on par with what you would find in in ants, I guess. :) $\endgroup$ Jun 22, 2017 at 15:53
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    $\begingroup$ You need swallows, not insects, they're famed for their cargo carrying capabilities. $\endgroup$
    – Separatrix
    Jun 22, 2017 at 17:14

2 Answers 2


Army ants can move about 20m/h, and move for 15 days at a time before stopping for 20 days to let the pupae hatch. Assuming they move for an average of 12 hours a day, they move ~3600m during their moving phase.

Oulu, Finland to Johannesburg, South Africa (over-land) is about 15,000km, give or take. I picked Oulu because it's about in the middle of Finland, latitude-wise. At 0.24km per day, that's ~62500 days of constant travel or about 171.2 years.

Air is probably faster.

Monarch butterflies famously migrate thousands of km each year. They can move about 50km/hr in still air, and faster with a tailwind, but probably less fast when they're carrying a rock in a big cluster. Assuming they're traveling at quarter-speed, they still move 40x the pace of our army ants, and they can travel in a more direct route - closer to 13,000km.

By this route, traveling the same average of 12 hours a day at 12.5km/h, a swarm of butterflies could easily make the trip in 90 days, probably faster if the butterflies are strong enough to carry the stones alone or in small groups.

Appropriately, butterflies are also often considered symbols of life, hope, and resurrection.


I missed the part earlier where the OP states that the stones are approximately grape-sized. Grapes apparently weigh about 5 grams. A stone of similar size might weigh 10-15 grams, however, butterflies can often carry 40x their own weight or more. This means that a single monarch butterfly weighing 0.5g could feasibly carry a single stone.

The length of the trip, therefore, depends on how fast they can fly while carrying the stones:

Full speed (50km/h): ~3 weeks
Half speed (25km/h): ~6 weeks

I don't think any land or aquatic arthropod will be able to touch that trip time.

  • $\begingroup$ That's super helpful! Something you didn't mention was the water-route; do you think any crustaceans would be able to transport the stones any meaningful distance? I'm also considering the idea of different local arthropods passing along the stone as it travels, so maybe ants for a while, butterflies for a while, crustaceans(?) for a while, etc. :) $\endgroup$ Jun 22, 2017 at 17:40
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    $\begingroup$ The water route would be a good deal longer, I think, going out around Europe and West Africa and down along the coast. Movement through water would be slower as well, because of the density. The only speeds I could find on crustaceans are on the order of 10-20km/h. Flying insects are probably your fastest route overall. $\endgroup$
    – Chris M.
    Jun 22, 2017 at 17:55


Ballooning spiders make balloons for the rocks and when the air current is correct they loft them into the skies to travel to their destination.

The wind speed becomes the issue with strong enough webs.

Alternatively they could help the butterflies from Chris M's answer.

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    $\begingroup$ Could be a neat narrative thing that the spiders' webs probably don't last the whole way, so the things just live everywhere, picking up rocks daily or so and sending them on their way when the winds are right. Like a flying underground railroad run by spiders. $\endgroup$
    – Delioth
    Jun 22, 2017 at 20:10

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