CLOSE
The Field Museum/Robby Heischman
The Field Museum/Robby Heischman

How Climate Change Shaped This Adorable Skunk’s Evolution

The Field Museum/Robby Heischman
The Field Museum/Robby Heischman

If you’re like many people, you’ve often thought, “Boy, am I sure glad there are lots of types of spotted skunks.” (Us too.) And thanks to science, we now know whom to thank for this wonderful diversity: climate change. A report on the sweet-faced skunks’ strange history was published this week in the journal Ecology and Evolution.


Robert C. Dowler

The western spotted skunk (Spilogale gracilis) is a button-nosed, wee critter, maxing out at around just 2 pounds. To maximize its stench-dispersal powers, the skunk flings itself into a little handstand, waving its back legs and rear in the air as noxious gas sprays from a gland under its tail.


Jerry W. Dragoo

For all its exotic appeal, S. gracilis is surprisingly local, making its home up and down the left side of North America from the temperate rainforests of the Pacific Northwest to the hottest desert in Mexico.

Speciation, or the splitting of one species into two, usually happens when two populations of organisms are divided by some physical boundary, like a mountain or a waterfall. Because the two groups are living in slightly different environments, they face slightly different pressures, and eventually evolve into slightly different creatures.

To find out if that’s what happened with S. gracilis, the authors of the current study collected DNA samples from 97 skunks in a range of habitats and areas of the American Southwest.


Sampling skunks is odiferous work.
The Field Museum

They found that the skunks could be divided into three subtypes. But the subtypes aren’t separated by rivers or mountain ranges, nor have they ever been. Instead, the researchers say, the family was split up by climate change a very, very long time ago.

“Western spotted skunks have been around for a million years, since the Pleistocene Ice Age,” lead author Adam Ferguson, of The Field Museum and Texas Tech University, said in a statement. “During the Ice Age, western North America was mostly covered by glaciers, and there were patches of suitable climates for the skunks separated by patches of unsuitable climates.”

It was largely these shifting patches of hostile terrain that kept the skunk families apart. These findings are important not only for lovers of skunk history, but for scientists, conservationists, and policy-makers who care about where our planet and its inhabitants are going.

“What we know about the past can inform what we expect to see in the future,” says Ferguson. “Understanding these genetic subdivisions that happened as a result of changing climatic conditions can help us conserve skunks and other animals in the future.”

nextArticle.image_alt|e
iStock
arrow
Animals
Where Do Birds Get Their Songs?
iStock
iStock

Birds display some of the most impressive vocal abilities in the animal kingdom. They can be heard across great distances, mimic human speech, and even sing using distinct dialects and syntax. The most complex songs take some practice to learn, but as TED-Ed explains, the urge to sing is woven into songbirds' DNA.

Like humans, baby birds learn to communicate from their parents. Adult zebra finches will even speak in the equivalent of "baby talk" when teaching chicks their songs. After hearing the same expressions repeated so many times and trying them out firsthand, the offspring are able to use the same songs as adults.

But nurture isn't the only factor driving this behavior. Even when they grow up without any parents teaching them how to vocalize, birds will start singing on their own. These innate songs are less refined than the ones that are taught, but when they're passed down through multiple generations and shaped over time, they start to sound similar to the learned songs sung by other members of their species.

This suggests that the drive to sing as well as the specific structures of the songs themselves have been ingrained in the animals' genetic code by evolution. You can watch the full story from TED-Ed below, then head over here for a sample of the diverse songs produced by birds.

[h/t TED-Ed]

nextArticle.image_alt|e
NOAA, Wikimedia Commons // Public Domain
arrow
Animals
Watch the First-Ever Footage of a Baby Dumbo Octopus
NOAA, Wikimedia Commons // Public Domain
NOAA, Wikimedia Commons // Public Domain

Dumbo octopuses are named for the elephant-ear-like fins they use to navigate the deep sea, but until recently, when and how they developed those floppy appendages were a mystery. Now, for the first time, researchers have caught a newborn Dumbo octopus on tape. As reported in the journal Current Biology, they discovered that the creatures are equipped with the fins from the moment they hatch.

Study co-author Tim Shank, a researcher at the Woods Hole Oceanographic Institution in Massachusetts, spotted the octopus in 2005. During a research expedition in the North Atlantic, one of the remotely operated vehicles he was working with collected several coral branches with something strange attached to them. It looked like a bunch of sandy-colored golf balls at first, but then he realized it was an egg sac.

He and his fellow researchers eventually classified the hatchling that emerged as a member of the genus Grimpoteuthis. In other words, it was a Dumbo octopus, though they couldn't determine the exact species. But you wouldn't need a biology degree to spot its resemblance to Disney's famous elephant, as you can see in the video below.

The octopus hatched with a set of functional fins that allowed it to swim around and hunt right away, and an MRI scan revealed fully-developed internal organs and a complex nervous system. As the researchers wrote in their study, Dumbo octopuses enter the world as "competent juveniles" ready to jump straight into adult life.

Grimpoteuthis spends its life in the deep ocean, which makes it difficult to study. Scientists hope the newly-reported findings will make it easier to identify Grimpoteuthis eggs and hatchlings for future research.

SECTIONS

arrow
LIVE SMARTER
More from mental floss studios