Killer whales also often target grey whale calves. they separate them from their mothers and drown them. Scientists suggest they do it for sport and entertainment, as they rarely consume the meat.
As much as I love orcas, it is indeed quite brutal seeing those battles play out between orcas and large whales. Gives you chill bumps and reminds you how tough nature is.
However, I've never heard of orcas routinely killing for sport, especially large whales. Is there an article or study you know of? It is not an easy kill for them, and I was under the impression that they do it for certain delicacies. For example, they will kill great white sharks specifically to eat their livers, which is insanely high in calories, and then nothing else of the shark.
I think they do typically consume the tongue of baby grey whales. I cant find an easy reference for the sport aspect, but many animals kill for entertainment/practice.
Scuba diving around Monterey CA we sometimes observe sea lions killing mola molas (ocean sunfish) for sport. The sea lions bite the fins off but don't eat more than a couple bites, they just leave the crippled fish to sink to the bottom and slowly die. One time I saw about 10 half dead molas laying on the seafloor flopping around.
There's seals, which they seem to kill for a combination of sport and to give the young orcas practice killing.
It's pretty hard to watch orcas use their tail to playfully bat dying seals 50' up in the air and not think they're doing it for fun. Even if there's a learning component to the purpose.
Orcas will tail slap things to stun or kill them, and some fish-eating orcas do this after corralling a school of fish together into a tight ball or cylinder. Then they swim in fast and slap the edges with their tails, either stunning or killing several fish that they can then just pick out of the floating water.
However, the seal punting the commenter was referring to does indeed seem to be for sport, play, training, or all of the above. Here's a video: https://youtu.be/G7WGIH35JBE?t=21
For one, it shows the sheer power of an orca. According to the NOAA Fisheries, a harbor seal (what transient orcas typically hunt) weights 24 pounds at birth and then 180-285 pounds as an adult. So, if we assume that seal in the video is an adolescent or an adult, the orca is launching something probably weighing at least 100-200 pounds about 50-100ft into the air. I do find it disturbing, but I have seen some cases where the orcas had played with a seal and then let it live.
This discussion of power reminded me of orcas hunting dolphins. The following videos might be harsh if you really like dolphins, but it shows the insane power and speed of an orca. They can move so fast in the water, jump tens of feet out of the water while weighing several tons, and ram things with such force killing them. That's also why I balk at calling them the wolves of the sea. I do not know of a single other predator that has the intelligence plus the insane physicality that they do. I think one would be hard pressed to find a more apex predator.
They play with their prey like cats do with mice. I remember seeing videos where they were throwing around half dead penguins for quite a while and then left the penguin without eating.
Trigger warning: https://www.youtube.com/watch?v=FsXBeoqVN0c