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Great White Sharks hunt seals near shore. The seals, in turn, hunt fish that often finds them going to sandy beaches where rivers meet the ocean. Humans like to swim and surf on these beaches. This forces contact between humans and the sharks.

Are there similar pressures to force Orca-human interactions?

Yes, orcas also hunt seals, sea lions, and other marine mammals that live on beaches. Orcas will even beach themselves in order to hunt these. And they've even been observed in freshwater rivers [1].

https://www.youtube.com/watch?v=AtF3FPyRVIw

https://www.youtube.com/watch?v=Ks40worW_gQ

https://youtu.be/HY-mefETVZ8?t=3m44s

https://www.youtube.com/watch?v=AkZKM47igpA

[1] http://marinebio.org/species.asp?id=84

> Great White Sharks hunt seals near shore.

Orcas do that too.

Are Oraca commonly found in water that won't cause hypothermia (eg death or unconsciousness) in less than an hour?

That would be warmer 50F==10C. Anecdotally, I have only seen or heard of people seeing Orca in the PNW and Arctic where swimming without a wet/dry suit is not only uncomfortable, but deadly.

Great White shark populations OTOH are concentrated in some of the most popular and temperate swimming areas in the world. Certainly, they are everywhere I have ever been swimming/diving.

http://voices.nationalgeographic.org/files/2013/02/1104_0729...

Good question. But according to this map[1] there should be plenty of beaches where orcas and humans might encounter each other.

Given that orcas are able to learn how to drown white sharks, and catch birds by baiting with fish, couldn’t it just be that they have learned not to hunt humans, as they’ve experienced retaliation in the past? I’m pretty sure pre-historic humans would somehow retaliate if an orca grabbed a child from the beach and, because of that, it would make sense if orcas have simply learned not to do this.

[1] https://dailyzooniverse.files.wordpress.com/2013/11/killerwh...

Orcas do have large populations near Antartica, Norway, and Alaska, but they also have large populations along the American West Coast, Mexico, and Australia. The Global Biodiversity Information Facility has some good maps of observation recordings around the world for these two species.

Orcas - https://www.gbif.org/species/2440483

Great white sharks - https://www.gbif.org/species/2420694

There is a surf spot in Morocco (Killers) named for the Orcas spotted there. They apparently show up periodically. Water is plenty warm.

orcas, with humans, are one of the most widely distributed mammals. they live nearly everywhere.

It is estimated that bears kill over two million salmon a year. Attacks by salmon on bears are much more rare.

Why though ? Why wouldn't orcas prey on humans when the occasion present itself ?

Exactly. I have no idea. It would make sense for a large, capable predator to try out eating a human, but they just don't. Maybe humans don't have enough fat on them to be appealing? ...but orcas also eat birds, which don't have a lot of fat. Maybe because orcas are intelligent collaborative hunters, they have instincts not to eat other intelligent species like humans? ...but orcas also eat dolphins, which are similarly intelligent hunters.

I would also expect any large predator to spontaneously act aggressive at times, but this very rarely happens. Or at some point I would expect it to make a mistake and kill a human even though it doesn't actually want to eat him/her, but this has apparently never happened.

I find it all very interesting, but I'm at a loss to explain it.

Orcas seem to have fairly specialised diets -- there's different subspecies, each of which eats something different.

https://seaworld.org/animal-info/animal-infobooks/killer-wha...

>Type A whales eat mostly Antarctic minke whales and have also been observed hunting southern elephant seals.

>Large type B whales eat mainly seals, especially Weddell seals, and also hunt minke whales.

>Small type B killer whales have been observed hunting penguins and are believed to mainly eat fishes.

>Type C killer whales mostly eat Antarctic toothfish (Dissostichus mawsoni).

>Little is known about the diet of type D killer whales, however, they have been observed preying on Patagonian toothfish (Dissostichus eleginoides) caught on longlines.

So if type C whales don't eat seals and type B whales don't eat fish, it's not surprising that no whale type likes to eat humans -- they're apparently just picky eaters.

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