There is a world somewhere between reality and fiction. Although ignored by many, it is very real and so are those living in it. This forum is about the natural world. Here, wild animals will be heard and respected. The forum offers a glimpse into an unknown world as well as a room with a view on the present and the future. Anyone able to speak on behalf of those living in the emerald forest and the deep blue sea is invited to join.
(10-19-2022, 07:14 PM)abadu Wrote: Hello everyone, my name is Miguel, I'm a biologist, currently taking a masters in Biostatistics, and have been working with wild marine mammals in Southern Portugal for the past year and a half, including orcas. The orcas here are small, so they don't help witht the question of the largest, but with a 5.17m and 2000kg stranded female, maybe it will help with someone's regression.
In terms of information, I've compiled some measurements of orcas in recent times that were confirmed by scientists. I'm going to talk about antarctic type A, B1, B2 and C, as no information regarding type D was found. ENP Residents and Transients, and finally some animals from museums in the North Atlantic. After all of that I'll give my own personal opinion, which is worth as much as any. Hope I'm helping with the discussion
From Size and body condition of sympatric killer whale ecotypes around the Antarctic Peninsula, Durban et al. (2021)
Type A
Male: 7.80m +/- 0.61m, n=6, max=8.92m
Female: 6.76m +/- 0.09m, n=10, max is unspecified, under but close to 7m
Type B1
Male: 7.58m +/- 0.29m, n=3, max is unspecified, under but close to 8m
Female: 6.93m +/- 0.35m, n=6, max=7.35m
Type B2
Male: 6.44m +/- 0.22m, n= 24, max is unspecified, several under 7m but over 6.5m
Female: 5.82m +/- 0.21m, n=35, max is unspecified, over 6m
In this study they also found out that B2's were the skinniest of the three ecotypes, which may reflect ecotype variation as well as a population close to carrying capacity
In A Dwarf Form of Killer Whale in Antarctica, Pitman et al. (2007), we get size estimates for Type C's and is also noted a maximum size for the Type A's in the southern Ocean of 9.2m in the abstract and later of 9.0m for males, it's mentioned that female type A's reach 7.7m and are on average 6.4m.
Type C
Male: 5.6m +/- 0.32m, n=65, max=6.1m
Female: 5.2m +/- 0.23m, n=33, max=5.8m
In Morphometrics of mammal-eating killer whales from drone photogrammetry, with comparison to sympatric fish-eating killer whales in the Eastern North Pacific, Kotik et al. (2021), transients and residents were compared, here I'll use this article only for the transients, as they are showed with much greater detail. It's also worth mentioning that this study focuses on Transients from the Salish sea to Vancouver Island, and it may not reflect the Californian transient population, neither the transients from the WN Pacific.
In SIZE AND BODY CONDITION OF SOUTHERN RESIDENT KILLER WHALES, Durban et al. (2009) they studied, as the name implies the southern resident kw population
In Ecological, morphological and genetic divergence of sympatric North Atlantic killer whale populations, Foote et al. (2009) analysed several museum specimens, with three that stand out in terms of size, the maximum size excluding these three is 6.6m, which is in line with what is known from the previously called ecotype ENA Type 1. Two of these three specimens come form Scotland (perhaps they were from the same population as the West Coast community) and one came from the Faroes Islands, and were 7.92m and 8.45m for the Scottish and 8.10m for the Faroese.
I didn't find any more reliable and relevant information from the North Atlantic.
Final Thoughts
Male KWs
In my opinion, it's reasonable to assume a maximum body lenght of 9m+ for the species, specially in Antarctic type A individuals, as one of the sampled ones was a 8.92m. The claim that is in Pitman et al. (2007) abstract of a 9.2m male Type A, seems reasonable and likely to be the case. Wouldn't be surprised if in the future, males even greater in lenght were to be found in this population. Their average size is also relatively close to the B1's, with a 0.22m diference, which may be explained by the low numbers of sampled individuals for both ecotypes. Taking that into account, I can't rule out that B1's may also grow greater than 8m and possibly to 9. I think it's safe to rule out B2's and C's, as they are among the smallest KW ecotypes, with the average type A being 1.36m and 2.2m longer than the average of each. Also both of their maximum sizes are smaller than the smallest male A. It's also safe to rule out Residents, or at least the southern Residents, as their maximum size is still smaller than the average Type A and B1, and along the same as the average Transient. Speaking of Transients, the 7.3m asymptopic lenght and a 8.3m maximum, supports them as being around the same size as the type A's and B1 and I wouldn't be surprised if there were males close to 9m or above. The 3 animals in the North Atlantic also support possible 8-9m KW in the area, and since the West Coast community is known to have animals bigger than those from other populations, and are also in the same are as two out of three of this big ones, they seem like good candidates for being amongst the biggest KW, morphometric analysis of John Coe and Aquarius need to happen in order to confirm that. The figures from whaling data of 9.2m in the southern ocean, 9.45m in the Pacific and 9.8m in the North Atlantic have now different support. I would say the Southern Ocean one is most likely accurate or the one that seems most probable to be accurate, based on the measurements cited above. The 9.45m is possible, but without any measurements from the Western North Pacific, I can't formulate a strong opinion, plus, we also don't have that much data on other Transient Killer whales, as some individuals like Lonesome George have been given estimates of 9.2-10m (30-33ft), despite not being confirmed. Finally, the biggest figure is also the one I find the hardest to believe, if the 9.8m figure came from the Southern Ocean, I'd rethink it, but still take it with a grain of salt, plus it has been said that the size was estimated and not measured so I wouldn't consider it reliable at all. In conclusion, I would say the saffest bet for the largest KW on record is 9-9.2m.
Female KWs
In previous posts on this thread, some figures in the Southern Hemisphere have poped up, like a 7.9m female from South Africa and the 7.7m long female type A's. I find it hard to believe that Type A females would reach 7.7-7.9m, taking into account the measurements presented before. 7.7-7.9m is much closer to the maximum registered size of confirmed B1 which has a 7.36m long female, taking into account that the biggest A in the study was less than 7m long. The only females close to B1 are transients with a maximum of 7.1m. No female of exceptional size was mentioned in the study in the North Atlantic, as the biggest was 6.1m, which, for me makes the claim of a 8.5m female in the North Atlantic seem unreasonable. With this, I would atribute the biggest females to the B1's and probably the 7.7-7.9m figures come from that ecotype, based on the present information, although I'd be more conservative and assume a maximum size of around 7.5m for females
Thanks for all the info everyone as managed to collect, this thread is really interesting, and I hope I managed to give new insights to some of you
Hi, and welcome to the forum.
Magnificent information, we really appreciate it. Your analysis is very good and help us to understand the body size that this magnificent animal can reach.
