CLOSE
Steffen Sanvig Bach, Maersk Oil Research and Technology Centre, Qatar
Steffen Sanvig Bach, Maersk Oil Research and Technology Centre, Qatar

Scientists Spy on Whale Sharks by Testing the Water They Swim In

Steffen Sanvig Bach, Maersk Oil Research and Technology Centre, Qatar
Steffen Sanvig Bach, Maersk Oil Research and Technology Centre, Qatar

Researchers have figured out how to monitor the genetic health of endangered whale sharks without ever touching them—by testing the waters they swim in. They described their progress in the journal Nature Ecology & Evolution.

Keeping tabs on endangered animals is an essential part of keeping them safe. Yet our current monitoring methods are imperfect at best. Some, like aerial monitoring, depend on clear weather and good visibility. Others, like tagging, can actually hurt [PDF] the animals they’re meant to protect. It’s time to find new ways to look out for our fellow animals.

One international research team came up with an interesting idea: rather than taking tissue samples from whale sharks’ bodies, what about testing the environment in which they swim?

Study author and geneticist Philip Francis Thomsen of the Natural History Museum of Denmark has been investigating the various uses of environmental DNA (eDNA) for the last few years. He and his colleagues found that testing the water is a great way to help scientists identify and count its piscine inhabitants. But they’d never used eDNA to examine a given fish population’s genetics—that is, how the members of the group are related to one another and others in their species.

Thomsen and an international team of his peers traveled to a site in the Persian Gulf where whale sharks like to congregate. First, they counted the number of fins at the surface to estimate how many sharks were around. Then they collected 20 small samples of seawater and small tissue samples from the sharks so they could compare their results.

They sequenced the DNA found in the tissue samples and the DNA in the water and found that the two yielded similar results. By combining these genetic family trees with their observations of the site, the researchers were able to estimate the number of sharks present. They found that the sharks in the gulf were more closely related to other populations in the Indian and Pacific Oceans than they were to Atlantic whale sharks.

There’s more work still to be done, the authors write, but this hands-off method shows a lot of promise. Whale sharks, if you're reading this: We'll keep you posted.

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