Data on braininess in mammals, part 6: brain mass relative to carcass mass in East African ungulates
Source:
my own fieldwork, 1985-1988, Wildlife Ranching and Research, later Swara Conservancy, now part of Nairobi National Park
Equus quagga boehmi
n=9
Giraffa tippelskirchi
males n=7
Adult females + males mean carcass mass 854.9 kg, mean brain mass 666.5 g (n=7)
Adult females mean carcass mass 430.1 kg, mean brain mass 654.2 g (n=4)
Adult males mean carcass mass 721.3 kg, mean brain mass 682.8 g (n=3)
Taurotragus oryx pattersonianus
Adult males mean carcass mass 316.2 kg, mean brain mass 427.9 g (n=5)
Nanger granti granti
Eudorcas thomsonii thomsonii
Alcelaphus cokii
Connochaetes albojubatus
female n=11
male n=14
to be continued in https://www.inaturalist.org/journal/milewski/96318-data-on-braininess-in-mammals-part-7-ontogenetic-progression-of-brain-mass-in-ruminants-from-birth-to-adulthood#...
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SURPRISINGLY LIMITED SEXUAL DIMORPHISM IN THE AFRICAN SAVANNA BUFFALO (SYNCERUS CAFFER CAFFER)
My reference is Skinner (1977, https://catalogue.nla.gov.au/catalog/648401 and https://academic.oup.com/jmammal/article-abstract/60/2/438/869280?login=false).
Also see two sets of data for S. caffer in https://www.inaturalist.org/journal/milewski/96065-data-on-braininess-in-mammals-part-3#.
In ontogenetic terms, growth is extended, in both sexes, for years beyond sexual maturity, as follows.
Body mass does not differ between the sexes up to 3.25 years old.
Females attain sexual maturity at 3.5 years old. At this stage, body mass is about 375 kg, which is only 66% of the fully mature body mass of females (570 kg, attained at about 14 years old).
Males attain fully mature body mass of about 675 kg at >15 years old.
This is a sexual difference of only about 100 kg. Thus, fully mature body mass of males is only 118% that of females.
The following illustrate that the African savanna buffalo is only modestly sexually dimorphic in body mass, despite the obvious difference in the horn-bosses:
https://www.youtube.com/watch?v=Y2_bx_8Imz4 and https://www.sciencephoto.com/media/389598/view/african-buffaloes-mating and https://www.wildandfreefoundation.org/wff-logbook-blog/how-to-tell-a-buffalo-cow-apart-from-a-bull and https://www.youtube.com/watch?v=R2hnF6KNQSk and https://www.alamy.com/stock-photo-african-buffalo-syncerus-caffer-bull-left-and-cow-illustrating-the-40138856.html and https://upload.wikimedia.org/wikipedia/commons/2/2a/Cape_Buffalo_%28Syncerus_caffer%29_bull_and_cow_..._%2853021591046%29.jpg and https://singita.com/2021/05/buffalo-horns/ and https://huntinginafricasafaris.com/project/cape-buffalo-cow-hunt-south-africa/ and https://provideofactory.com/video/african-buffalo-mating and https://stock.adobe.com/au/video/african-buffalo-mating/204576023 and https://elements.envato.com/african-buffalo-mating-M9LWJZ9 and https://www.alamy.com/cape-buffalo-mating-african-buffalo-mating-image342277723.html and https://stock.adobe.com/images/mating-cape-buffalo/132676782 and https://www.sciencephoto.com/media/461273/view/african-buffalo-mating.
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