Orca are known predators of Sperm Whales
https://www.theguardian.com/environ...h-sperm-whales-orcas-indian-ocean-in-pictures
They display predator behavior to groups of Bulls and only back off when it seems they can’t get an inch. That’s not behavior of an animal afraid of Sperm Bulls but very similar to lions with wildebeest if they can’t get a vulnerable member out of a herd.
Predation fails more often than not as a rule in nature, so I’m not surprised by these examples but Orca are known to hunt humpback whales and go for their calves.
I don’t really care about comparing a well documented animal like orca to Megalodon, especially with the recent changes and reported tonnage increase with its elongated body. Too many unknowns for an animal of that size
Orcas prey on sperm whales, yes - I don't argue otherwise.
The main thing for me is that there's an image of them being very successful at it, even with grown adults, which as you've pointed out isn't the case.
I'm also familiar with both incidents you've shared here:
- The Pitman one is more of an outlier than the norm. I'm pretty sure that the study described the group as females, possibly large subadults at that, with around 9 in total. The orcas numbered 17 and increased to 35 as the hunt continued, and the sperms did not really attempt to defend themselves.
For reference, most other attacks, even on females, end in failure to my knowledge. I actually don't know of any other case where predation was successful. There was a recent one where three juveniles defended themselves effectively and finished the whole thing by literally crapping into the orcas faces.
- The second incident where bulls were attacked happened because they were attempting to prevent the orcas from hunting the vulnerable calves and the females with them.
AFAIK this is one of the only two contexts where orcas go out of their way to attack male sperms, and the latter usually put up adequate defence or even chase the killers
away. The other is even rarer, and it happens when the two
contest for prey near fishing trawlers. Orcas tend to win by chasing the sperms away if the sperm whales are less aggressive.
I'll finish up by saying that, again, I do think orcas are the most dominant predator currently - even male sperms are pretty wary of them as Cure et al proved.
The main annoyance I have is that they sometimes treated as basically unstoppable to nonhuman predators.
Fair enough regarding the Meg; although we do know enough about them to conclude that they easily fed on orca sized predators, it is indeed pretty hypothetical.
Also I will say, you're the first person I've seen talking of a tonnage increase. What specific estimates have you seen?
Many estimates pre- Megalongdon were absolutely bloated IIRC, often crossing 65 tons on average and 100+ tons at max.
The lengthening and thinning actually seems to have brought it to a more reasonable maximum of 94-100 tons at 24 meters, at least in my experience.