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When Armor Met Lips

mannykannot
13 replies
23h29m

"Pinnipeds evolved about thirty million years ago. They showed up first in the colder parts of the northern hemisphere, then in the Antarctic, then in temperate zones."

That's an interesting sequence, given that the continents then were about where they are now.

ricardobeat
9 replies
23h22m

Maybe they evolved in both places independently, or maybe it took a couple million years for a pod of seals to make the journey from north to south, and then start dominating the local ecosystem.

ivanbakel
8 replies
19h4m

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?

DabbyDabberson
4 replies
18h17m

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

jasonwatkinspdx
2 replies
17h57m

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.

throwway120385
0 replies
2h16m

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.

riffraff
0 replies
10h58m

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.

tetromino_
0 replies
4h40m

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
0 replies
9h6m

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

[2] https://www.ocearch.org/tracker/detail/dr-brent

[3] https://www.wur.nl/en/show/seal-telemetry.htm

ekanes
0 replies
18h54m

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.

ducttapecrown
0 replies
38m

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.

thriftwy
0 replies
21h44m

It takes one volcanic winter for them to cross the oceans and emerge on the other side, without being fit for the warm waters.

nateb2022
0 replies
23h0m

It is possible that they fed on extremophiles which thrived in really cold regions and later evolved to feed on other food sources.

aendruk
0 replies
15h37m

That’s the sequence of notable populations; individuals did who knows what.

HankB99
6 replies
23h58m

geology nerd

Shouldn't that be "paleontology nerd?"

skavi
4 replies
22h42m

See footnote 1

nearbuy
2 replies
22h3m

The footnotes for the article are in the first comment. The author put a humorous footnote about being pedantic.

jjtheblunt
0 replies
19h19m

And, in doing so, was pedantic!

angiosperm
0 replies
15h11m

Paleontology used to be a subspecialty of geology, for a long time after they proved fossils had once been animals. Which the geologists had to do.

vitiral
4 replies
19h29m

I really enjoyed this article, but I was really disappointed. For some reason I thought it was going to evolve into a Lovecraftian epic of how the grand and horrifying civilization of the ancient cephalopods and their relatives was thwarted by another species, one who paved the way for our own ignorant and doomed civilization to thrive.

I kept this feeling until the very end [spoiler] even when it was revealed to be seals I held out hope they could be a Lovecraftian player in a grand epic saga.

csours
3 replies
18h58m

who do you think is protecting us from the lovecraftian horrors?

vitiral
1 replies
18h51m

In general? Mostly ignorance. From cephalopods? I guess it's the seals

leashless
0 replies
18h18m

Italian love of calamari.

Muromec
0 replies
8h37m

Paperclip counting bureaucrats of course

readyplayernull
4 replies
14h58m

If you’re inclined to be pedantic about the nautilus’ limbs and say that /actually/ they are “arms” and not “tentacles” because tentacles have suckers on them, then (a) congratulations on remembering that long-ago biology class, and (b) see Footnote 1, above.

Something tells me an arm is a mechanical limb composed of connected poles that turn at their joints. And a hose-like limb without suckers should have its own name. A foot is an "arm", a penis is something else.

zem
0 replies
1h36m

you don't need a new name, "tentacle" is fine and does not imply suckers. see hydra e.g.

pineaux
0 replies
11h13m

Penis is definitely something else because it contains (almost) no muscles, while your other examples do (contain muscles).

nehal3m
0 replies
14h12m

Hey, speak for yourself!

Karellen
0 replies
8h56m

Also, tails

jimkleiber
4 replies
1d

I thoroughly enjoyed the author's writing style. Anyone know where I can find more by him, Doug Muir?

jimkleiber
1 replies
23h20m

Normally a blog just lets me click the author's name and see more by them, and even the link you posted doesn't really show more essays.

This one did though: https://crookedtimber.org/author/doug-muir/

pizzalife
0 replies
17h20m

Personally I can't stand it, yeah?

pfdietz
3 replies
22h24m

"So, you’re saying the nautiloids did okay until the pinnipeds sealed their fate?"

Terr_
2 replies
20h11m

I'm nautiloid to say more about their spiral into the depths.

klipt
0 replies
16h59m

Never trust a pinnipedophile.

jagged-chisel
0 replies
17h8m

ಠ_ಠ

teruakohatu
1 replies
14h55m

That is interesting. I looked it up on wikipedia and the Argonaut / Paper Nautilus "shell" is a thin walled eggcase and that males do not have. It does not provide protection.

angiosperm
0 replies
10h27m

Female argonauts have the shell their whole life long, and do not only construct it when they have eggs to put in it. We may reasonably assume that it has survival value even when there are no eggs. We know, for example, that they carry bubbles in it to tune their buoyancy.

a3w
2 replies
10h39m

So the ideal tank buster is a carnivorous unicorn: penetrate that armor, then schlorp out the crew! Genetics will go too far, if we ever get these.

h2odragon
1 replies
4h48m

That's why the graceful, horse shaped unicorns of classical times died out; and what we have now is the up-armored, heavyweight rhinoceros version.

Evolution is amazing innit.

throwway120385
0 replies
2h14m

A fascinating case of how gunpowder has shaped biology.

Affric
1 replies
17h13m

Great photo selection with the shifty looking seal (gotta love the whites of caniform eyes) and a nice little summary of the article.

One thing about zoology and animal morphology is that we all know how important feeding is for animals but only real nerds love the digestive tract. Transport, skin, and reproduction are far more glamorous; but the mammalian sense of smell and mouth parts gave us such an advantage in the tertiary period.

It’s interesting that this sort of feeding never arose in the sea. I wonder what the ancestors of the pinnipeds who first ventured back into water ate…

jrflowers
0 replies
14h34m

It is a shame that this is not about when Armour Meats perfected their hot dog formulation

alexey-salmin
0 replies
12h53m

"Ah! Love! The only thing my armor can't withstand!"

JKCalhoun
0 replies
18h10m

I wanted to go fossil hunting (and for ammonites in particular) after watching these guys just haul them out:

https://youtu.be/9XWhdPL58is

CoolGuySteve
0 replies
4h10m

If you find this evolutionary history interesting then I can't recommend PBS Eons enough. It's a great youtube series on the subject: well researched, a dense but breezy pace, and the paleo art + fossil images help convey information without being overly dry.

Here's the one about this subject: https://www.youtube.com/watch?v=3vQ55ToQeWI