Does Diving Limit Brain Size in Cetaceans?

Marino, Lori; Sol, Daniel; Toren, Kristen L.; Lefebvre, Louis

doi:10.1111/j.1748-7692.2006.00042.x

Cited by 29 publications

(33 citation statements)

References 48 publications

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“…increased blood volume and myoglobin levels in muscle tissue) commonly observed in diving marine mammals (Worthy & Hickie, 1986). Moreover, Marino et al. (2006) found that dive constraints do not influence relative brain size investment in cetaceans (whales, dolphins and porpoises) and argued that large muscle mass associated with increased body mass primarily influences the duration of cetacean dives.…”

Section: Discussionmentioning

confidence: 99%

Sexual selection uncouples the evolution of brain and body size in pinnipeds

Fitzpatrick

Almbro

Gonzalez‐Voyer

et al. 2012

J of Evolutionary Biology

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The size of the vertebrate brain is shaped by a variety of selective forces. Although larger brains (correcting for body size) are thought to confer fitness advantages, energetic limitations of this costly organ may lead to trade-offs, for example as recently suggested between sexual traits and neural tissue. Here, we examine the patterns of selection on male and female brain size in pinnipeds, a group where the strength of sexual selection differs markedly among species and between the sexes. Relative brain size was negatively associated with the intensity of sexual selection in males but not females. However, analyses of the rates of body and brain size evolution showed that this apparent trade-off between sexual selection and brain mass is driven by selection for increasing body mass rather than by an actual reduction in male brain size. Our results suggest that sexual selection has important effects on the allometric relationships of neural development.

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Section: Discussionmentioning

confidence: 99%

Sexual selection uncouples the evolution of brain and body size in pinnipeds

Fitzpatrick

Almbro

Gonzalez‐Voyer

et al. 2012

J of Evolutionary Biology

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“…Despite an extensive fossil record, surprisingly little is known about the tempo of the neocete radiation. It has, however, been suggested to have been 'explosive', driven by the evolution of key characters relating to sociality and brain size (Marino et al 2006), echolocation and baleen as key innovations in the odontocetes and mysticetes, respectively (Fordyce 1992), or radiation into vacant niches following the extinction of archaeocete lineages in the Early Oligocene (Fordyce & de Muizon 2001;Fordyce 2003;Clementz et al 2006).…”

Section: Introductionmentioning

confidence: 99%

Diversity versus disparity and the radiation of modern cetaceans

et al. 2010

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Modern whales are frequently described as an adaptive radiation spurred by either the evolution of various key innovations (such as baleen or echolocation) or ecological opportunity following the demise of archaic whales. Recent analyses of diversification rate shifts on molecular phylogenies raise doubts about this interpretation since they find no evidence of increased speciation rates during the early evolution of modern taxa. However, one of the central predictions of ecological adaptive radiation is rapid phenotypic diversification, and the tempo of phenotypic evolution has yet to be quantified in cetaceans. Using a time-calibrated molecular phylogeny of extant cetaceans and a morphological dataset on size, we find evidence that cetacean lineages partitioned size niches early in the evolutionary history of neocetes and that changes in cetacean size are consistent with shifts in dietary strategy. We conclude that the signature of adaptive radiations may be retained within morphological traits even after equilibrium diversity has been reached and high extinction or fluctuations in net diversification have erased any signature of an early burst of diversification in the structure of the phylogeny.

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“…Cetaceans possess a number of adaptations that aid diving, including increased myoglobin levels (i.e., an oxygen-storing and iron-carrying protein found in the muscles of all mammals); increased blood volume; and a higher concentration of hemoglobin than in terrestrial mammals [120]. However, dive limits are also dictated by rates of oxygen consumption, which is of particular relevance when discussing a very oxygen-sensitive organ like the brain.…”

Section: Discussionmentioning

confidence: 99%

“…What is more, those that dive regularly, e.g., sperm whales, have the highest concentrations. Indeed, sperm whales are better than any other animal at staying underwater for long periods without having to take air (e.g., they can stay underwater for approximately 73 min at a time [120]). Diving mammals have higher concentrations of this protein, but according to Mirceta et al [131] they also exhibit an adaptation: the surface of this oxygen-binding protein possesses a net surface charge causing it to repel itself more strongly, thus enabling deep diving animals to pack their myoglobin into even higher concentrations (proteins tend to stick together at high concentrations impairing their function).…”

Section: Terrestrial Mammals Lacking Internal Granular Layer IV In Thmentioning

confidence: 99%

Is Cetacean Intelligence Special? New Perspectives on the Debate

Chinea

2017

Entropy

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Abstract:In recent years, the interpretation of our observations of animal behaviour, in particular that of cetaceans, has captured a substantial amount of attention in the scientific community. The traditional view that supports a special intellectual status for this mammalian order has fallen under significant scrutiny, in large part due to problems of how to define and test the cognitive performance of animals. This paper presents evidence supporting complex cognition in cetaceans obtained using the recently developed intelligence and embodiment hypothesis. This hypothesis is based on evolutionary neuroscience and postulates the existence of a common information-processing principle associated with nervous systems that evolved naturally and serves as the foundation from which intelligence can emerge. This theoretical framework explaining animal intelligence in neural computational terms is supported using a new mathematical model. Two pathways leading to higher levels of intelligence in animals are identified, each reflecting a trade-off either in energetic requirements or the number of neurons used. A description of the evolutionary pathway that led to increased cognitive capacities in cetacean brains is detailed and evidence supporting complex cognition in cetaceans is presented. This paper also provides an interpretation of the adaptive function of cetacean neuronal traits.

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Does Diving Limit Brain Size in Cetaceans?

Cited by 29 publications

References 48 publications

Sexual selection uncouples the evolution of brain and body size in pinnipeds

Sexual selection uncouples the evolution of brain and body size in pinnipeds

Diversity versus disparity and the radiation of modern cetaceans

Is Cetacean Intelligence Special? New Perspectives on the Debate

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