CLOSE
istock
istock

6 Animals That Are Rapidly Evolving

istock
istock

We sometimes think of evolution as a thing of the past, but it continues today, especially as environmental pressures force humans and animals to adapt to survive. Here, a few examples of animals evolving in real-time.

1. The lizard with extra sticky feet

The native green lizards that occupy the lower branches and trunks of Florida’s trees got a rude awakening when their invasive cousins, the brown lizards, moved in. Faced with limited resources and double the competition, the green lizards made a move: they abandoned the lower branches for the treetops. Up there, the limbs are thinner and smoother, so the green lizards’ bodies had to adapt to the environmental shift. To better cling to the smooth branches, their toepads grew bigger and their scales got stickier—in just 15 years and about 20 generations. “The degree and quickness with which they evolved was surprising," said Yoel Stuart, a postdoctoral researcher in the College of Natural Sciences at The University of Texas at Austin and lead author of the study. "If human height were evolving as fast as these lizards' toes, the height of an average American man would increase from about 5 foot 9 inches today to about 6 foot 4 inches within 20 generations." 

2. The shrimp that lost its eyes

In the process of evolutionary change, you either use it or you lose it—and this is certainly true for a group of cave-dwelling crustaceans. These crabs and shrimp live underground where there is no light, and the sense of sight doesn’t do much good. As a result, they’ve gone blind, relying on smell and touch to navigate the cavernous depths. When researchers compared the brains of these spelunkers to their land-dwelling relatives, they found that not only are these creatures sightless, they’re actually losing the parts of their brains associated with vision. Meanwhile, the areas that control touch and smell are getting bigger. "It's a nice example of life conditions changing the neuroanatomy," the study’s lead author, Dr. Martin Stegner, from the University of Rostock in Germany, told the BBC. It’s taken about 200 million years for the brain changes to occur, which may not seem “rapid,” but as the Washington Post’s Rachel Feltman says, it’s “a relatively short time, in the evolutionary scheme of things.”

3. The owls that are changing color

Climate change is forcing many animals to adapt to survive. The tawny owl in Finland is a good example. These creatures come in two colors, brown or pale grey. The cold white winters have traditionally favored the grey owls, which can hide from predators by blending into a snowy color scheme. But as the winters have become more mild over the last 50 years, researchers noticed a shift: grey owls are on the decline and the brown birds are thriving, better suited to blending into the bare brown branches of the forest. As more brown owls survive, more brown genes get passed down through generations. Until now, the researchers say, “an evolutionary response to a quantified selection pressure driven by climate change has not been empirically demonstrated in a wild population.”

4. The fish that’s migrating earlier

Climate change is also the driving force behind a recent behavioral shift in pink salmon. As water temperatures rise, the fish are migrating from the ocean to the river to spawn about two weeks earlier than they did 40 years ago. And this isn’t just a new behavior—it’s actually a change at the genetic level. Between the 1980s and 2011, the number of late-migrating salmon declined by 20 percent, according to Ryan Kovach, a population ecologist at the University of Alaska in Fairbanks. The change happened over just one or two generations, which suggests organisms can adapt to climate change very quickly. “We show that there has been a genetic shift towards earlier migration timing through what appears to be natural selection against the late-migrating individuals in the population,” Kovach says

5. The bedbugs with super-strength

Unfortunately, our long-running battle with these bed-hopping pests has backfired, producing bedbugs with thicker shells and nerve cells of steel to resist the harsh chemicals we lob at them. Bedbugs in New York City are now 250 times more resistant to pesticides than the bedbugs in Florida, according to researchers at the University of Massachusetts in Amherst. "Insect resistance is nothing more than sped-up evolution," says insect toxicologist John Clark. 

6. The mouse that’s immune to poison

Bad news for anyone with a fear of mice: researchers have discovered a house mouse with an immunity to Warfarin, a type of poison typically deployed to fight infestations. The super mice were discovered in Germany, where the lowly house mouse bred with its poison-resistant distant cousin the Algerian mouse. The result? A hybrid mouse with a very useful genetic mutation that gives it a leg up over its rodent relatives. Usually hybrid animals can’t reproduce, but "sometimes there is the occasional odd hybrid that has just about the right novel combination of genomes from two species that renders them, at least temporarily, superior over the pure species," says the study’s lead author Michael Kohn. “We’ve caught evolution in the act.” 

All images courtesy of iStock unless otherwise noted.

nextArticle.image_alt|e
iStock
arrow
science
DNA Analysis of Loch Ness Could Reveal the Lake's Hidden Creatures
iStock
iStock

Stakeouts, sonar studies, and a 24-hour video feed have all been set up in an effort to confirm the existence of the legendary Loch Ness Monster. Now, the Associated Press reports that an international team of scientists will use DNA analysis to learn what's really hiding in the depths of Scotland's most mysterious landmark.

The team, led by Neil Gemmell, who researches evolutionary genetics at the University of Otago in New Zealand, will collect 300 water samples from various locations and depths around the lake. The waters are filled with microscopic DNA fragments animals leave behind as they swim, mate, eat, poop, and die in the waters, and if Nessie is a resident, she's sure to leave bits of herself floating around as well.

After extracting the DNA from the organic material found in the water samples, the scientists plan to sequence it. The results will then be compared to the DNA profiles of known species. If there's evidence of an animal that's not normally found in the lake, or an entirely new species, the researchers will hopefully spot it.

Gemmell is a Nessie skeptic, and he says the point of the project isn't necessarily to discover new species. Rather, he wants to create a genetic profile of the lake while generating some buzz around the science behind it.

If the study goes according to plan, the database of Loch Ness's inhabitants should be complete by 2019. And though the results likely won't include a long-extinct plesiosaur, they may offer insights about other invasive species that now call the lake home.

[h/t AP]

nextArticle.image_alt|e
iStock
arrow
Animals
10 Biting Facts About Snapping Turtles
iStock
iStock

Here in the Americas, lake monster legends are a dime a dozen. More than a few of them were probably inspired by these ancient-looking creatures. In honor of World Turtle Day, here are 10 things you might not have known about snapping turtles.

1. THE COMMON SNAPPING TURTLE IS NEW YORK'S OFFICIAL STATE REPTILE.

Elementary school students voted to appoint Chelydra serpentina in a 2006 statewide election. Weighing as much as 75 pounds in the wild (and 86 in captivity), this hefty omnivore’s natural range stretches from Saskatchewan to Florida.

2. ALLIGATOR SNAPPING TURTLES CAN BE LARGE. (VERY LARGE.)

An alligator snapping turtle
NorbertNagel, Wikimedia Commons // CC BY-SA 3.0

Utterly dwarfing their more abundant cousin, alligator snappers (genus: Macrochelys) are the western hemisphere’s biggest freshwater turtles. The largest one on record, a longtime occupant of Chicago’s Shedd Aquarium, weighed 249 pounds.  

A monstrous 403-pounder was reported in Kansas during the Great Depression, though this claim was never confirmed.  

3. COMMON SNAPPERS HAVE LONGER NECKS AND SPIKIER TAILS.

Alligator snappers also display proportionately bigger heads and noses plus a trio of tall ridges atop their shells. Geographically, alligator snapping turtles are somewhat restricted compared to their common relatives, and are limited mainly to the southeast and Great Plains.

4. BOTH VARIETIES AVOID CONTACT WITH PEOPLE.

If given the choice between fight and flight, snapping turtles almost always distance themselves from humans. The animals spend the bulk of their lives underwater, steering clear of nearby Homo sapiens. However, problems can arise on dry land, where the reptiles are especially vulnerable. Females haul themselves ashore during nesting season (late spring to early summer). In these delicate months, people tend to prod and handle them, making bites inevitable.

5. YOU REALLY DON'T WANT TO GET BITTEN BY ONE. 

Snapping turtle jaw strength—while nothing to sneeze at—is somewhat overrated. Common snapping turtles can clamp down with up to 656.81 newtons (N) of force, though typical bites register an average of 209 N. Their alligator-like cousins usually exert 158 N. You, on the other hand, can apply 1300 N between your second molars.

Still, power isn’t everything, and neither type of snapper could latch onto something with the crushing force of a crocodile’s mighty jaws. Yet their sharp beaks are well-designed for major-league shearing. An alligator snapping turtle’s beak is capable of slicing fingers clean off and (as the above video proves) obliterating pineapples.

Not impressed yet? Consider the following. It’s often said that an adult Macrochelys can bite a wooden broom handle in half. Intrigued by this claim, biologist Peter Pritchard decided to play MythBuster. In 1989, he prodded a 165-pound individual with a brand new broomstick. Chomp number one went deep, but didn’t quite break through the wood. The second bite, though, finished the job.

6. SCIENTISTS RECENTLY DISCOVERED THAT THERE ARE THREE SPECIES OF ALLIGATOR SNAPPING TURTLES.

A 2014 study trisected the Macrochelys genus. For over a century, naturalists thought that there was just a single species, Macrochelys temminckii. Closer analysis proved otherwise, as strong physical and genetic differences exist between various populations. The newly-christened M. suwanniensis and M. apalachicolae are named after their respective homes—namely, the Suwannee and Apalachicola rivers. Further west, good old M. temminckii swims through the Mobile and the Mississippi.

7. THANKS TO A 19TH CENTURY POLITICAL CARTOON, COMMON SNAPPING TURTLES ARE ALSO KNOWN AS "OGRABMES." 

Snapping turtle cartoon
Urban~commonswiki via Wiki Commons // CC BY PD-US

Drawn by Alexander Anderson, this piece skewers Thomas Jefferson’s signing of the unpopular Embargo Act. At the president’s command, we see a snapping turtle bite some poor merchant’s hind end. Agitated, the victim calls his attacker “ograbme”—“embargo” spelled backwards.

8. ALLIGATOR SNAPPERS ATTRACT FISH WITH AN ORAL LURE …

You can’t beat live bait. Anchored to the Macrochelys tongue is a pinkish, worm-like appendage that fish find irresistible. Preferring to let food come to them, alligator snappers open their mouths and lie in wait at the bottoms of rivers and lakes. Cue the lure. When this protrusion wriggles, hungry fish swim right into the gaping maw and themselves become meals.

9.  … AND THEY FREQUENTLY EAT OTHER TURTLES. 


Complex01, WikimediaCommons

Alligator snappers are anything but picky. Between fishy meals, aquatic plants also factor into their diet, as do frogs, snakes, snails, crayfish, and even relatively large mammals like raccoons and armadillos. Other shelled reptiles are fair game, too: In one Louisiana study, 79.82% of surveyed alligator snappers had turtle remains in their stomachs.

10. YOU SHOULD NEVER PICK A SNAPPER UP BY THE TAIL.

Ideally, you should leave the handling of these guys to trained professionals. But what if you see a big one crossing a busy road and feel like helping it out? Before doing anything else, take a few moments to identify the turtle. If it’s an alligator snapper, you’ll want to grasp the lip of the upper shell (or “carapace”) in two places: right behind the head and right above the tail.

Common snappers demand a bit more finesse (we wouldn’t want one to reach back and nip you with that long, serpentine neck). Slide both hands under the hind end of the shell, letting your turtle’s tail dangle between them. Afterwards, clamp down on the carapace with both thumbs.

Please note that lifting any turtle by the tail can permanently dislocate its vertebrae. Additionally, remember to move the reptile in the same direction that it’s already facing. Otherwise, your rescue will probably turn right back around and try to cross the road again later. 

SECTIONS

arrow
LIVE SMARTER