Pregnant Monkey's Rafting Across the Ocean

I wonder how people think about the great ocean rafting hypothesis required to explain the biogeography of monkeys, and many other species

Monkeys crossed the Atlantic Ocean. Really. Some biologists will tell you that humans (and all other apes) are monkeys in an evolutionary sense, so you could say that monkeys have voyaged over the Atlantic many times…in boats, starting with the Vikings, and, later, in planes. But millions of years earlier, monkeys in the normal sense—ones with fur and long tails and no boat-building skills—almost certainly made an unlikely and accidental ocean crossing from Africa to South America.

When I bring up this case of the ocean-crossing monkeys, scientists and non-scientists alike often react with undisguised incredulity. Even people who would normally take me seriously are likely to flash a bemused smile. After all, how could monkeys possibly get across the Atlantic? Even if they were aboard some sort of natural raft (like a clump of vegetation), wouldn’t they die of thirst or starvation long before the trip was over? On “intelligent design” websites, creationists have even argued that the willingness of evolutionists to believe that monkeys crossed the Atlantic just shows how far scientists will go to support Darwin’s theory. (To drive that point home, one website features a cartoon of two monkeys on a raft, arms outspread like Kate Winslet and Leonardo DiCaprio on the Titanic , with a sign proclaiming “Brazil or Bust.”).


This natural experiment shows how it makes sense for sea creatures, but I’m curious how strong the evidence is for mammals.

A post was split to a new topic: Evolution’s Challenged with Biogeography?

If you want to talk biogeography you need to read this book:

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The best part of the evolution news post is Luskin relies on molecular studies to make his argument. Molecular studies they always dispute. Molecular studies are flawed when they solve a mystery for evolution. Valid when they cause a “problem” for evolution. :+1:t2::+1:t2:

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This is Matzke’s area. It’d be nice to have him drop in

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It seems that the cognitive difficult here is real.

  1. Clearly we are dealing with a very rare event, perhaps requiring unusual circumstances or large landslide to create a flotsam raft.

  2. However this only has to happen a few times over several millions of years. So even if the rate is low, because the event is rare, it is a big number it is multiplied with to get a probability.

So what is the likelihood this took place? Some very tiny number multiplied by some very large number. How tiny? This is very difficult to compute. It could be so rare as to be unobservable through all of human civilization, but still be occurring frequently enough to explain the data. How large? It is not immediately obvious, be we do not know actually know the time window to multiply the rate.

It turns out that we, cognitively, have a very difficult time managing very small numbers multiplied by very large numbers, especially if there is uncertainty over either. With this in mind, it is not surprising that it is seen as a problem for evolution. It might just be one of those unexpected and non-intuitive features of the world, that arises from millions of years of history.


I’m pretty sure @art knows him and can invite him here.

You really need to read the book I linked to. So many fascinating examples and so many cool observations which made me dismiss this anti common ancestry argument very quickly. The argument seems to me to be the exact same as the conflicting phylogenies argument. Ignore the strong signal of common ancestry and focus of the few conflicts.

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Thanks for the recommendation. Just ordered the book!

Isn’t there another number involved? The likelihood of a pregnant monkey populating a continent?
Would that be tiny?
Has this been studied through population genetics by the way… i.e whether the current populations could have been derived from one organism?

The current population of New World monkeys, around a hundred species arising from an event in the Late Eocene? Sure, population genetics can give you an answer on that by next Tuesday.

I have an alternate hypothesis based on one large no: and one small no:…
An :alien: abducted monkeys and took them to the new world… one small no: is the chance of aliens turning up on earth… the large no: is the possible no: of worlds that might have intelligent life… :wink:

What should we name the first male and first female new world monkeys?


I do see how this would interest Joshua. What can genetics tell us about the “first” new world monkeys?

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This jumped out at me in the material which Joshua quoted:

This brings to mind another group of creationists, non-ID-oriented, at Answers in Genesis who frequently speak of vast numbers of animals returning to their native lands after the Noahic flood by means of these same types of floating debris “islands”.


Anchor babies on rafts? Send more troops to the Texas border!!! :clown_face:


This does not appear to be a tiny likelihood. Foreign species often do very well when introduced to new ecologies. Let’s say it is a 50/50 chance. Also keep in mind we only see the winners in the fossil record. We have no idea how many crossing took place where the monkey ends up failing to establish a population and grow.

The monkey’s pregnancy, by the way, is tongue in cheek. I’d venture it is more likely if there was more than one individual in the flotsam.

A low figure would be problematic…As it would require the low probability event to happen more than once… I can think of many ways a few monkeys that finished a harrowing journey across the ocean could end up dead…
Anyway, it’s ultimately about unknown figures like you said.

Yup, you are getting tripped up by the tiny number multiplied by the large number. The large number is very large, 10s of millions of years.