Data on braininess in mammals, part 4: Carnivora in the southwestern part of South Africa, according to Sheppey and Bernard (1984)

Sheppey and Bernard (1984, https://www.ajol.info/index.php/az/article/view/152830 and https://www.tandfonline.com/doi/epdf/10.1080/02541858.1984.11447899?needAccess=true)

The following is arranged in decreasing order of EQ (encephalisation quotient). I have assumed that the volume if the brain in millilitres is equivalent to brain mass in grams. An asterisk* indicates Herpestidae.

• Aonyx capensis body mass 14.0 brain mass 108 EQ 2.08
• Panthera pardus body mass 26.1 brain mass 144 EQ 2.07 (this is an exaggerated value, because body mass is greatly underestimated in this study)
• Mellivora capensis body mass 10.3 kg brain mass 88 g EQ 1.89
• Lycaon pictus body mass 26.5 kg brain mass 131 g EQ 1.86
• Lupulella mesomelas body mass 7.8 kg brain mass 56 g EQ 1.30
• Parahyaena brunnea body mass 42.0 kg brain mass 120 g EQ 1.29
• Lutra maculicollis body mass 4.5 kg brain mass 49 g EQ 1.28
• Caracal caracal body mass 11.4 kg brain mass 62 g EQ 1.28
• Crocuta crocuta body mass 68.0 kg brain mass 155 g EQ 1.19
• Leptailurus serval body mass 10.4 kg brain mass 54 g EQ 1.16
• (I suspect that Panthera pardus actually belongs here)
• Acinonyx jubatus body mass 50.0 kg brain mass 117 g EQ 1.12
• Vulpes chama body mass 2.65 kg brain mass 32 g EQ 0.90
• Felis lybica body mass 4.3 kg brain mass 34 g EQ 0.90
• Proteles cristatus body mass 9.4 kg brain mass 39 g EQ 0.86
• *Atilax paludinosus body mass 2.76 kg brain mass 29 g EQ 0.81
• Panthera leo body mass 161.5 kg brain mass 217 g EQ 0.81
• Otocyon megalotis body mass 3.2 kg brain mass g 27 EQ 0.75
• Felis nigripes body mass 2.0 kg brain mass 25 g EQ 0.73
• *Herpestes ichneumon body mass 2.94 kg brain mass 24 g EQ 0.67
• *Ichneumia albicauda body mass 3.38 kg brain mass 23 g EQ 0.63
• Genetta genetta body mass 1.85 kg brain mass 17 g EQ 0.50
• Genetta tigrina body mass 1.72 kg brain mass 17 g EQ 0.50
• *Herpestes pulverulentus body mass 0.77 kg brain mass 11 g EQ 0.34
• Ictonyx striatus body mass 0.68 kg brain mass 10 g EQ 0.31
• *Mungos mungo body mass 0.79 kg brain mass 10 g EQ 0.31
• *Suricata suricatta body mass 0.68 kg brain mass 10 g EQ 0.31
• *Cynictis penicillata body mass 0.93 kg brain mass 10 g EQ 0.30
• *Herpestes sanguineus body mass 0.44 kg brain mass 7 g EQ 0.22
• Poecilogale albinucha body mass 0.36 kg brain mass 5 g EQ 0.16
• *Helogale parvula body mass 0.27 kg brain mass 5 g EQ 0.16

My commentary:

This study is valuable for its original data on brain size.

One of the most noteworthy findings is the great difference in braininess between Panthera leo (EQ=0.8) and Lycaon pictus (EQ=1.9).

These two carnivores have coexisted widely in Africa, despite the brawny 'top-carnivore' killing the 'underdog' at every opportunity. Lycaon pictus survives partly by virtue of its far greater braininess.

The authors failed to proofread an error in the body mass of Panthera pardus. The value stated is 26.1 kg, whereas what they meant was presumably 62.1 kg. This led to a great exaggeration of the encephalisation quotient of P. pardus, which is instead likely to be about 1.0 (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5043137/ and https://www.researchgate.net/publication/229958542_Brain_size_of_the_lion_Panthera_leo_and_the_tiger_P_tigris_Implications_for_intrageneric_phylogeny_intraspecific_differences_and_the_effects_of_captivity).

It is puzzling that all the *Herpestidae in the study have encephalisation quotients <1. Suricata suricatta is well-known for its intelligent behaviour (https://www.dailymail.co.uk/sciencetech/article-2187573/Meerkats-intelligent-humans-thought.html and https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3414518/ and https://www.sciencedaily.com/releases/2013/02/130204220845.htm and https://www.theguardian.com/science/2023/sep/25/psychologists-investigate-meerkats-response-to-human-emotions and https://www.britannica.com/animal/meerkat).

Helogale parvula, like S. suricatta (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5043137/), probably should have an encephalisation quotient >1, instead of the value of 0.16 reported by Sheppey and Bernard (1984).

I suspect that this underestimation of the braininess of small carnivores reflects a problem in the mathematics of allometry across such a large range in body masses.

Posted on 24 June, 2024 09:31 by milewski