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.
Bushfires like the ones that have ravaged Australia and California this year, could become the new norm for the generation that has been born in the last decade, an example of how our perception of ecological change is defined by what has happened in our lifetime (Image Credit: dm4244, CC BY-SA 4.0, Image Cropped)
It’s no secret that our world has undergone rapid changes in the last few decades. Extreme weather events are becoming almost the norm and species seem to be going extinct every minute. But as depressing as this may seem, the general doom and gloom we hear about the world on a daily basis still only represents a small percentage of the ills we’ve inflicted on our planet since we’ve been here.
The Japanese skeleton shrimp is responsible for the reduction of many Norwegian local species who flee in terror because LOOK AT IT (Image Credit: Erling Svensen, CC BY 4.0)
Today’s creatures look horrific. Or they would, at least, if they weren’t so tiny. A long-range invader, the Japanese skeleton shrimp (Caprella mutica) is tiny, but their ability to colonise new areas quickly has made them a problem for other aquatic invertebrates since their first sighting in Norway 20 years ago.
Species such as this Carribean reef shark have higher extinction risks than most fish. But how effective are our management efforts? (Image Credit: Albert kok, CC BY-SA 2.0, Image Cropped)
Reef accessibility impairs the protection of sharks (2018) Juhel et al., Journal of Applied Ecology 55
The importance of sharks goes well beyond what Jaws did to Hollywood, or one week in the USA each July. In any reef ecosystem, sharks perform a key functional role, exerting top-down pressure, stabilising food webs, and improving general ecosystem functioning. They’re also ‘charismatic’ species, meaning they’re easier to raise funding for, and bring money in through tourism. Yet pressure from fishing suggests that reef shark populations may be under threat, and with high body sizes and long lifespans, their populations are more sensitive than most to overfishing, making extinction risks higher.
Yet the lack of data on shark populations means that the effectiveness of the few existing management programs is largely untested. This paper looks at Marine Protected Areas (MPAs), areas in which national or international bodies prevent fishing or even entry, to see whether or not they are an effective conservation method for shark populations.
The Greater Canada Goose, one of many species on Norway’s Alien Species List (Image Credit: Bernard Spragg, CC0 1.0, Image Cropped)
Guest post by Malene Nygård