Post by theropod on Jun 9, 2015 16:39:50 GMT 5
Now every stranding is not subject to publication and there are
certainly stranding from large bulls like this one which was alone while
stranded (just like the holotype).
news.bbc.co.uk/2/hi/science/nature/3437455.stm
Plus, the stranding seems not to be clear as I said...
certainly stranding from large bulls like this one which was alone while
stranded (just like the holotype).
news.bbc.co.uk/2/hi/science/nature/3437455.stm
Plus, the stranding seems not to be clear as I said...
I’m not saying that large bulls can’t fall victim to it, I’m saying that based on one report of a stranding that I looked at, specimens that would correspond to fully grown males are very rare, and strandings represent one of the best sources for sperm whale data that died of natural causes (because obviously whales that die in the ocean are rarely, if ever found).
The lack of large bulls may be due that the papers studying stranded specimens are not that common either. Or simply 18 m bulls are just normally rare ? remember that Ellis (2011) reports that few exceeded 18 m.
They are rare, that's my point (hence why any individual specimen is unlikely to correspond to it]. Individuals around 15m are already quite large, and that's below the average size at physical maturity.
I usually consider adult Physeter immune to any predation excluding humans. Based on this, I even expect less this huge physeteroid to have been preyed even by a potentiall larger, more powerful megalodon. Note that there is still the possibility of not-so mammal specialist diet for Livyatan...
You get a point. I think the best potential material are the preserved teeth that could maybe indicate the age of the animal. But for now between the paper and the various communication I had with several people working on the specimen, I think there is no indication for a disease or predation related death. But of course nothing definitive to say here.
I get that. Where we differ is that I don't require evidence for that, it is simply my default assumtion. Same with it being a large adult, until there is evidence suggesting otherwise I am considering it to be just normal-sized.
I think it is naturally assumed that adults fossil physeteroids found are full grown or did not have much to grow left. Individually, I don't think why these specimens are not at their proper peak size.
That is just as speculative as what I wrote-just lless likely imho.
Also it's obviously not the case with specimens of extant phseteroids such as those cited in the supplement of Lambert et al.. These were obviously adults for the most part, but obviously some of the males weren't fully grown yet, based on their small size. Nonetheless, no indication whatsoever about their state of maturity.
I get that you mean fossil animals because tjey died of natural causes, but see beloow (the large-predator fossil record isn't biased towards fully grown specimens, neither are thhe largest sauropods btw).
That full grown status to not be determined in studies you mean ?
Well, in L.melvillei it obviously wasn't determined, direct evidence is completely lacking. What I'm saying is just that based on other taxa it is unlikely to be a big individual, as even giant apex predators usually don't live to "achieve their lives". To test thia assumption, think of T.rex for example, an animal that, like Livyatan is unlikely to be preyed upon; only one in tens of specimens fits the "fullly grown, could have died of old age"-category. If giant predators predominantly died of this cause, this would be reflected in the fossil record of such animals, but it isn't (instead we even see a bias towards young animals in some of them).
The situation seems to be similar in physeteroids, but as I wrote, I aam going to research that more thoroughly before making final conclusions.
Either way, for now I consider these sizes comparable, and I'd be interested in seeing the scale. We'll see.
Yes but that would suggests that Livyatan was larger on average than meg and Physeter and I don't think anything supports this.
