November 21, 2016 | David F. Coppedge

Mammal Champs Strut Their (Unevolved) Stuff

Here’s a showcase of very different mammals all deserving of the same thing: admiration. You don’t do that by attributing them to evolution.

Hard soils no headache for pocket gopher ( A buck-toothed gopher may not be your garden’s best friend, but you have to admire the little furball. This article says it can chew right through hard ground because of its sturdy skull design. Where did that come from?

The evolutionary secrets of an extraordinary North American rodent are being uncovered by University of Queensland School of Biological Sciences researchers.

The pocket gopher features prominently in a study of how mammals’ skulls can evolve over a short time frame to cope with environmental conditions.

UQ scientist Dr Vera Weisbecker said that through different evolutionary pathways, pocket gophers obtained a skull that allowed them to dig in hard soils.

It doesn’t seem to bother Dr Weisbecker that since “skull adaptation can happen very quickly,” that implies that mutations had to hurry up and happen on demand. But we digress. Back to this mammal’s award: “each gopher could move 1 tonne of soil per hectare per year, using 360 to 3400 times more energy than walking the same distance.”

Cat brains: what gives? ( The photo of the cheetah at full speed, eyes focused on its target, says more than all the evolutionary fluff in the article. Scientists at Michigan State became distracted by an evolutionary conundrum: “The brains of wild cats don’t necessarily respond to the same evolutionary pressures as those of their fellow mammals, humans and primates, indicates a surprising new study led by a Michigan State University neuroscientist.” Unlike primate brains, cat brains show no consistent relationship between sociality and frontal lobe size. “So what gives?” Interested readers can listen in on the speculation game if they want. “Studying feline brain evolution has been a bit like herding cats,” said Sakai, MSU professor of psychology and neuroscience. “Our findings suggest the factors that drive brain evolution in wild cats are likely to differ from selection pressures identified in primate brain evolution.” So the “social brain hypothesis” is falsified. Now back to cat watching.

Huddled mice could change the way we think about evolution (The Conversation): Ignore the cute picture of baby mice piled together like pillows on each other. Stuart P. Wilson and James V. Stone are busy working the deep dark secrets of evolution. It’s not intuitive, you see. Only experts can determine the tricky hand of Darwinism, understanding aspects that are “not obvious” to the layman. We interrupt this program to announce the Stupid Evolution Quote of the Week:

This result is particularly interesting for two reasons. First, it shows that behavioural adaptations that happen within the lifetime of an animal, such as huddling, could alter the course of evolution. This is not obvious given that the genetic information we possess essentially remains fixed throughout our lifetimes.

BM-EmperorCharlie-smSecond, because huddling is an example of self-organising behaviour among a group of animals, our results suggest that this example may be ideal for exploring how self-organisation affects evolution more generally. Self-organisation describes how a collection of simple entities (like a group of cold rats) can create something more complex (like a huddle) without any instruction. Like natural selection, self-organisation shapes everything in the natural world, from the formation of snowflakes to the translation of genetic code into bodies and brains.

Certain aspects of self-organisation are reasonably well understood, but how self-organisation interacts with natural selection is not one of them. So understanding how huddling affects the evolution of temperature regulation might help shed light on one of the most fundamental questions in biology: how do self-organisation and natural selection interact to shape the natural world?

Maybe the mice just like each other’s fur. What’s Darwin got to do with it? Now, back to the cute pictures. Awww. Look at that happy mouse trouncing through the snow, so well equipped for winter sports.

Narwhal echolocation beams may be the most directional of any species (Science Daily): It’s been a long time since we shared news about these arctic long-toothed whales, the narwhals. Now, a new report says that they win the echolocation prize. German researchers found that “the narwhal emits echolocation clicks with the most directional beam of all echolocators.” Maybe sonar designers could learn a thing or two.

Brazilian free-tailed bat is the fastest flyer in the animal kingdom: Bats are not just skilful [sic] aviators, they can also reach record-breaking speeds (Science Daily). Talk about putting the story in the headline. Now you know what this is about. These bats beat out common swifts, which can top out at 100 kilometers per hour. The bat record is 160 km per hour. “Their aerodynamic body shape and longer than average wings compared to other bat species enable them to reach such vast speeds.” Peregrine falcons can reach 300 kmh in dives, but that’s not during normal flight. The scientists who measured this feat with radio transmitters were astonished, considering how small and lightweight these mammals are:

Animals with long and narrow wings usually fly faster than those with shorter and wider ones. For this reason, the scientists selected the Brazilian free-flying bat (Tadarida brasiliensis) for their study. Even the experts themselves were surprised by their results: “Initially, we could hardly believe our data, but they were correct: at times, the female bats, which weigh between 11 and 12 grams, flew at speeds of over 160 kilometers per hour — a new record for horizontal flight,” says Kamran Safi from the Max Planck Institute for Ornithology.

Remember, too, that the bats echolocate while flying, change direction rapidly, and catch insects on the wing. It’s hard to believe that bats belong in the same Class Mammalia as narwhals and cheetahs. But can they sing?

Geneticists hope to unlock secrets of bats’ complex songs (Nature): Indeed, bats can sing. They trill. They bark. They screech. They whistle. “They use these sounds during courtship and mating, when they retrieve food and as they defend their territory against rivals,” the article says. Singing appears unrelated to the better-known echolocation clicks. “Bats sing just as birds and humans do,” the writer says. “But how they learn their melodies is a mystery — one that scientists will try to solve by sequencing the genomes of more than 1,000 bat species.” An initial survey of four species shows that male bats apparently learn how to sing from their fathers, brothers or conspecifics. A whole new field of study is opening up, Nature says: the study of vocal learning in bats.

Bats’ echolocation ability has been studied for many years, partly because of its applications to sonar and radar. But scientists know very little about the acoustic communication and social behaviour that drive how bats learn their songs and sounds, says Michael Yartsev, a neurobiologist at University of California, Berkeley. The study of vocal learning in bats is “nearly completely untapped”, he says — likening it to the state of research into birdsong 60 years ago.

It’s not going to be as simple as attributing this skill to a mutation in the FOXP2 gene, as is often done to explain the evolution of human language. “FOXP2 seems to have evolved to be much more diverse in bats than in people, Knörnschild says. The reason why is a mystery.

You will learn a lot more about nature from these articles if you strip out the evolutionary speculations. But as a news service, CEH sometimes feels a need to include the comics.








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