Tag Archives: brain
The thought of an orca playing with its food – a cute seal – can be a grim one. But is it useful to project our ideas of morality and emotion onto other species? (Image Credit: Christopher Michel, CC BY 2.0, Image Cropped)
Guest post by Mary Shuttleworth
Scene: A lone seal on a piece of ice, surrounded by an expanse of deep and frosted blue. The scene would be romantic, except the water is rippling. Every now and then dark fins with streaks of white emerge, jostling the ice. It is an orca, and it is in training. Members of its family, or pod, are nearby, watching it as it practices how to take down its prey. The seal is in distress, stress resonating throughout its body. If they have noticed, the orcas take no notice. They are learning how to hunt. More than that, it appears that they could even be playing.
Rodents and primates are periodically cited as some of the more intelligent animals on the planet, but it turns out that the large brains that these mammals possess have evolved more than once in their history. (Image Credit: Drow male, Arjan Haverkamp, ltshears, CC BY-SA 4.0, Image Cropped)
Encephalization and longevity evolved in acorrelated fashion in Euarchontoglires but not in other mammals (2018) DeCasien, Alex R., Evolution, DOI: doi:10.1111/evo.13633
Some of the most striking footage from documentaries like the recent “Blue Planet II” involve organisms that display remarkable intelligence (the octopus that uses shells to disguise itself and hide from its shark predators was a particular favorite of mine). As humans, we sometimes assume that we have the best brains on the planet and have somewhat of a monopoly on intelligence, so it’s always fascinating and maybe even surprising to see other animals using their own brains to solve problems. In mammals, brains that are larger than expected have evolved more than once, which is somewhat of a surprise given how costly a big brain is. For example, your brain needs 20% of the oxygen that your body uses, so one out of every five breaths is exclusively for your brain.
Larger brains are also correlated with longer lives, relative to the group that the organism in question belongs to. Historically, studies on brain size and longevity have been dominated by primate species, so the concern was that this long life/large brain trend may only be a primate trend, instead of generalizable to all mammals. The authors of this study wanted to analyze this trend across more mammal groups, in addition to studying the relationship between larger brains and longer lives.
This parasitic fungus takes over the brain and then ejects its spores out of the ant’s head (Image Credit: Erich G. Vallery, USDA Forest Service – SRS-4552, Bugwood.org, CC BY 3.0 US)
Mind Control: How Parasites Manipulate Cognitive Functions in Their Insect Hosts (2018) Libersat et al., Frontiers in Psychology, https://doi.org/10.3389/fpsyg.2018.00572
The field of neuro-parasitology is a relatively new field in biology and deals with the study of parasites that manipulate the nervous system of their hosts for their own gain (usually at the expense of the host). The authors of this review focused on host-parasite interactions between insect hosts and their myriad of parasites, due not only to most studies in this field being done with insects, but also the fact that most animals on the planet are in fact insects.