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Wikipedia says pinnipeds are monophyletic, so there's only a single evolutionary branch they originated from. The travel question is much more interesting. Nap

Wikipedia says pinnipeds are monophyletic, so there's only a single evolutionary branch they originated from. The travel question is much more interesting. Napkin math puts the distance between the polar circles at 12500 miles, the max swim speed of a seal at 25mph, giving a travel time of ~3 weeks of nonstop swimming as the crow flies. How does that happen? What would a pod of Arctic seals have eaten along the way, and what would have compelled them to make the trip out of familiar territory? How and why did they cross the temperate equatorial seas with a load of blubber?

ekanes 3y ago
Agree, this stuff is fun to imagine. Check out the many species that landed (and then kept evolving in isolation) in Hawaii. Seals, many birds, etc.
DabbyDabberson 3y ago
Look up monkey raft theory. How did monkeys from Africa get to South America? Also roughly 30 MYA.
- jasonwatkinspdx 3y ago
  Life travels on the ocean a lot farther than people realize, and often species you'd find improbably. Ants spread around the world by hitching rides on coconuts or waterbirds. This now means there's something like a global war among various ant colonies that invade each other this way.
  - deleted 3y ago
    [deleted]
  - riffraff 3y ago
    It's my understanding the ant spreading was more related with increase in navigation than birds/floating. that'd be why the Argentine ant has spread everywhere in Europe in the last century rather than being ubiquitous since the dawn of time.
  - throwway120385 3y ago
    I thought Wind, Wings and Waves to be a pretty interesting description of how species made it to Hawaii. Basically it either gets picked up in storms or large clumps of land make it across the ocean. Life only has to make the journey seldom or almost never and then take hold once to get to a new place.
- tetromino_ 3y ago
  Could an iceberg with a few seal families on it have drifted from the Arctic to the Antarctic? Presumably in the tropics the seals would have had a bad time and gone hungry and overheated, but once they got to cooler waters again, they would have been surrounded by food they love with zero competitors.
ricardobeat 3y ago
The distance is not surprising, animal trackers have shown they routinely travel vast distances in the ocean [1, 2, 3]. All you need is a fluke event, once in a thousand years where they for some reason make, and survive, this trip (I say thousand to give us some scale, could be actually once in a million years). [1] https://www.ocearch.org/tracker/detail/nukumi https://www.ocearch.org/tracker/detail/nukumi [2] https://www.ocearch.org/tracker/detail/dr-brent https://www.ocearch.org/tracker/detail/dr-brent [3] https://www.wur.nl/en/show/seal-telemetry.htm https://www.wur.nl/en/show/seal-telemetry.htm
ducttapecrown 3y ago
Well the ocean was filled with free floating ammonites, so maybe food wasn't an issue. Another commenter suggests a volcanic winter to lower the sea temps enough for the seals to cross.

ekanes 3y ago

Agree, this stuff is fun to imagine. Check out the many species that landed (and then kept evolving in isolation) in Hawaii. Seals, many birds, etc.

DabbyDabberson 3y ago

Look up monkey raft theory. How did monkeys from Africa get to South America? Also roughly 30 MYA.

jasonwatkinspdx 3y ago
Life travels on the ocean a lot farther than people realize, and often species you'd find improbably. Ants spread around the world by hitching rides on coconuts or waterbirds. This now means there's something like a global war among various ant colonies that invade each other this way.
- deleted 3y ago
  [deleted]
- riffraff 3y ago
  It's my understanding the ant spreading was more related with increase in navigation than birds/floating. that'd be why the Argentine ant has spread everywhere in Europe in the last century rather than being ubiquitous since the dawn of time.
- throwway120385 3y ago
  I thought Wind, Wings and Waves to be a pretty interesting description of how species made it to Hawaii. Basically it either gets picked up in storms or large clumps of land make it across the ocean. Life only has to make the journey seldom or almost never and then take hold once to get to a new place.
tetromino_ 3y ago
Could an iceberg with a few seal families on it have drifted from the Arctic to the Antarctic? Presumably in the tropics the seals would have had a bad time and gone hungry and overheated, but once they got to cooler waters again, they would have been surrounded by food they love with zero competitors.

ricardobeat 3y ago

The distance is not surprising, animal trackers have shown they routinely travel vast distances in the ocean [1, 2, 3]. All you need is a fluke event, once in a thousand years where they for some reason make, and survive, this trip (I say thousand to give us some scale, could be actually once in a million years). [1] https://www.ocearch.org/tracker/detail/nukumi https://www.ocearch.org/tracker/detail/nukumi [2] https://www.ocearch.org/tracker/detail/dr-brent https://www.ocearch.org/tracker/detail/dr-brent [3] https://www.wur.nl/en/show/seal-telemetry.htm https://www.wur.nl/en/show/seal-telemetry.htm

ducttapecrown 3y ago

Well the ocean was filled with free floating ammonites, so maybe food wasn't an issue. Another commenter suggests a volcanic winter to lower the sea temps enough for the seals to cross.