Relative Brain Size and Feeding Strategies in the Chiroptera

Eisenberg, John F.; Wilson, Don E.

doi:10.2307/2407489

Cited by 132 publications

(107 citation statements)

References 8 publications

(19 reference statements)

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“…Brain sizes for dataset 1 (Americas) were measured directly by determining endocranial capacity, the space inside the cranium [27]. All species included in this dataset were terrestrial mammals from the Americas.…”

Section: Materials and Methods (A) Brain And Body Measuresmentioning

confidence: 99%

Brain size is correlated with endangerment status in mammals

Abelson

2016

Proc. R. Soc. B.

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Increases in relative encephalization (RE), brain size after controlling for body size, comes at a great metabolic cost and is correlated with a host of cognitive traits, from the ability to count objects to higher rates of innovation. Despite many studies examining the implications and trade-offs accompanying increased RE, the relationship between mammalian extinction risk and RE is unknown. I examine whether mammals with larger levels of RE are more or less likely to be at risk of endangerment than less-encephalized species. I find that extant species with large levels of encephalization are at greater risk of endangerment, with this effect being strongest in species with small body sizes. These results suggest that RE could be a valuable asset in estimating extinction vulnerability. Additionally, these findings suggest that the costbenefit trade-off of RE is different in large-bodied species when compared with small-bodied species.

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Section: Materials and Methods (A) Brain And Body Measuresmentioning

confidence: 99%

Brain size is correlated with endangerment status in mammals

Abelson

2016

Proc. R. Soc. B.

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“…three-dimensional versus two-dimensional) habitat likely requires higher cognitive abilities. The size of the brain and some of its parts was suggested to be an indicator of the complexity of a species' habitat (Mace et al 1981;Eisenberg and Wilson 1978;Jacobs et al 1990;Safi and Dechmann 2005). For example, arboreal sciurids have relatively larger brains than terrestrial sciurids (Meier 1983), whereas subterranean rodents have relatively smaller brains than their surface-dwelling relatives (Vassallo andEcheverria 2009, but see Hafner andHafner 1984).…”

Section: Testes Size and Parasite Species Richnessmentioning

confidence: 99%

Does investment into “expensive” tissue compromise anti-parasitic defence? Testes size, brain size and parasite diversity in rodent hosts

2010

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Species richness of parasite assemblages varies among host species. Earlier studies that searched for host-related determinants of parasite diversity mainly considered host traits that affect the probability of host encounter with parasites, whereas host traits related to defensibility against parasites have rarely been investigated. From the latter perspective, evolutionary investment in "expensive" tissue or organs (like testes or brain) may trade off against energetically costly anti-parasitic defences. If so, richer parasite assemblages are expected in hosts with larger testes and brains. We studied the relationships between testes and brain size and diversity of parasites (fleas, gamasid mites and helminths) in 55 rodent species using a comparative approach and application of two methods, namely the method of independent contrasts and generalized least-squares (GLS) analysis. Both phylogenetically correct methods produced similar results for flea and helminth species richness. Testes size positively correlated with flea and helminth species richness but not gamasid mite species richness. No correlation between brain size and species richness of any parasite group was found by the method of independent contrasts. However, GLS analysis indicated negative correlation between brain size and mite species richness. Our results cast doubt on the validity of the expensive tissue hypothesis, but suggest instead that larger testes are associated with higher parasite diversity via their effect on mobility and/or testosterone-mediated immunosuppression.

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“…These cranial capacities were converted into brain weights using the volumetric weight of brain tissue (Ebinger 1974). Cranial capacity is larger than brain volume (Ro¨hrs and Ebinger 1978) but it is a reliable estimator of brain size (Eisenberg and Wilson 1978). The same conversion was applied to records obtained from the references if necessary.…”

Section: Definition Of Variables and Data Collectionmentioning

confidence: 99%

“…This has led to the derivation of the foraging strategy hypothesis (Martin 1984) which states that locating relatively large pockets of energy-rich food that have an unpredictable temporal and spatial distribution requires the use of a complex information centre that involves the co-ordination of different sense organs. This system has to be capable of storing and retrieving information efficiently, leading to the evolution of larger brains (Eisenberg and Wilson 1978). In addition, the sensorimotor skills required to harvest and manipulate food before ingestion could also promote the evolution of larger brains [extractive foraging hypothesis, (Dunbar 1992(Dunbar , 1995(Dunbar , 1998].…”

Section: Introductionmentioning

confidence: 99%

Gregariousness increases brain size in ungulates

Pérez‐Barbería¹,

Gordon

2005

Oecologia

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The brain's main function is to organise the physiological and behavioural responses to environmental and social challenges in order to keep the organism alive. Here, we studied the effects that gregariousness (as a measurement of sociality), dietary habits, gestation length and sex have on brain size of extant ungulates. The analysis controlled for the effects of phylogeny and for random variability implicit in the data set. We tested the following groups of hypotheses: (1) Social brain hypothesis-gregarious species are more likely to have larger brains than non-gregarious species because the former are subjected to demanding and complex social interactions; (2) Ecological hypothesis-dietary habits impose challenging cognitive tasks associated with finding and manipulating food (foraging strategy); (3) Developmental hypotheses (a) energy strategy: selection for larger brains operates, primarily, on maternal metabolic turnover (i.e. gestation length) in relation to food quality because the majority of the brain's growth takes place in utero, and finally (b) sex hypothesis: females are expected to have larger brains than males, relative to body size, because of the differential growth rates of the soma and brain between the sexes. We found that, after adjusting for body mass, gregariousness and gestation length explained most of the variation in brain mass across the ungulate species studied. Larger species had larger brains; gregarious species and those with longer gestation lengths, relative to body mass, had larger brains than non-gregarious species and those with shorter gestation lengths. The effect of diet was negligible and subrogated by gestation length, and sex had no significant effect on brain size. The ultimate cause that could have triggered the co-evolution between gestation length and brain size remains unclear.

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Relative Brain Size and Feeding Strategies in the Chiroptera

Cited by 132 publications

References 8 publications

Brain size is correlated with endangerment status in mammals

Brain size is correlated with endangerment status in mammals

Does investment into “expensive” tissue compromise anti-parasitic defence? Testes size, brain size and parasite diversity in rodent hosts

Gregariousness increases brain size in ungulates

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