haha

@Jefromi this comment was the first thing I saw on my phone when I woke up

by that time, I had completely forgotten about seals and whales

and it hit me completely out of context

I see a green, familiar looking face.

The Grinch?

I almost didn't look before I crawled into bed. You're killing me here.

:D

only just got in

car battery was flat

no cables, no neighbours

had to call a guy out, then go and get a new battery, then fit it, then get the train

I seriously have to bed to bed right now. Wow that sucks. Tell me all about it tomorrow?

that's about it :D

but go, sleep

g'night hon

g'night

@rumtscho They also know to hold sharks upside down to immobilize them!

Smart!

Big sharks?

@Cerberus Wiki says orcas in New Zealand eat sharks and rays, and lists several species, which seem to be in the few meter range.

also:

> In one incident filmed near the Farallon Islands in October 1997, a 4.7–5.3-metre (15–17 ft) female killed a 3–4-metre (9.8–13.1 ft) great white shark,[36] apparently after swimming with it upside-down in her mouth and inducing tonic immobility in it.

The reference is: prbo.org/cms/docs/marine/MMS.pdf

(that's near San Francisco)

@Jefromi in a rare twist of fate, your second message about sharks was also the first thing for me to see after waking, because I fell asleep in the afternoon today.

as for the whales, holding sharks to immobilize them sounds like a human meeting a rattlesnake and grasping it behind the head to prevent a bite

@rumtscho ha! I was merely hoping for slightly out of context, that's even better.

in a word, unnecessary bravado

@Jefromi Wow! Very impressive.

I dunno, I'm guessing it's less risky to hit hard and hold it that way, rather than letting go and hoping it's injured enough to not fight back.

But I am not an orca :)

maybe they are just showing off!

@rumtscho Probably true...but then a killer whale has a much thicker skin: can a white shark truly hark it?

They could just abstain from eating sharks, and swim away when they meet them?

@Jefromi Why not?

there surely is easier prey in the sea. Like seals.

@rumtscho I hear some people raise their cats as vegetarians.

Maybe... they need big food, though, and I'm guessing seals aren't plentiful everywhere? It did say that sharks and rays appeared to be important prey in New Zealand.

And seals are actually reasonably dangerous too - it's why they do things like the throwing in the air.

@Cerberus I think those people are known as owners of dead cats...

@Cerberus I think a shark has good chances to injure an orca. They are eating machines.

@derobert Yes, it's silly.

@rumtscho I suppose it could bite (off) the orca's fins or tail.

I think I will watch this tonight before I fall asleep. Then I'll surely know if the shark can hurt the whale.

I wonder what the mechanism behind tonic immobility is

> For tiger sharks (measuring 3–4 metres in length), tonic immobility can be induced by humans placing their hands lightly on the sides of the animal's snout in the area surrounding the eyes.

Now we know what to do when a tiger shark attacks us!

Imagine taking a vacation somewhere exotic, swimming in the water, and seeing the fin approach you at an impossible speed

@rumtscho odd thing to evolve too, especially since it sounds like happens in the wild—so it's not just a weird "well, it never happened until humans showed up..."

would you have the presence of mind to aim for the snout and pray it's a tiger shark and not another shark?

@derobert well, not all traits are advantegeous

> in sharks exhibiting the behaviour, some scientists relate it to mating, arguing that biting by the male immobilizes the female and thus facilitates mating.

That sounds plausible

when you are a shark, you eat everything

Including apparently your girl's nose...

I once watched a documentary which showed that sharks get pregnant. Their caviar hatches in the mother's body. Then, the strongest baby sharks eat the not yet hatched caviar and their weaker siblings before getting born.

The documentary represented the sharks as having eating instincts eclipsing everything else

so it sounds plausible that there will be a state turning off these instincts during mating

yeah

@rumtscho yeah, it's really weird, huh?

@rumtscho It's still a dangerous state to have, since it can be exploited by predators!

And it is apparently overridden by the smell of dead shark, so why is it not overridden by the attack of an orca?

@Cerberus yes it is dangerous, but if couplings consist of one partner eating the other, this would be even more dangerous for the species.

Also, if you watched the above video and want something to prevent nightmares

But it would make more sense to either require an additional trigger (the close proximity of a fellow shark), or to be overridden by the attack of an orca.

Again, the smell of dead shark overrides the reflex.

Evolution is not about choosing the most sensible design

So why doesn't the attack of an orca override it?

Or the attack of any predator.

^

Small sharks have the reflex too.

And in them the reflex is also overridden when they smell dead shark.

it doesn't override it, because it didn't evolve to override it.

Of course.

Why haven't sharks in which the reflex isn't overridden by a predator attack lost the battle of natural selection to sharks in which it is?

The override mechanism is already in their bodies.

Are there sharks in which the reflex is overriden by predators?

Eeek, what a topic...

@Stephie you don't like sharks?

what is sunny England doing?

Fine, I guess. We just brexited half an hour ago ;-)

Oh. And you are now getting bored in a car with Internet access?

No, I got 30 minutes free on the ferry

(I'm the driver today.)

@rumtscho I don't know.

@Stephie Haha welcome back.