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Photo by Stephanie Ware, The Field Museum.
Photo by Stephanie Ware, The Field Museum.

Given the Opportunity to Cheat on Their Mates, City Falcons Stay True

Photo by Stephanie Ware, The Field Museum.
Photo by Stephanie Ware, The Field Museum.

City life is a singular experience. We cram ourselves into territories far too small to support us and stack our homes on top of one another. We encounter other people at a rate that would have shocked and terrified our ancestors. In order to survive the city’s stresses and compression, we build up, we speed up, and we toughen up. For better or for worse, we change. And the same holds true for other animals. But some things stay the same; experts say that, even in crowded conditions, Chicago’s peregrine falcons stick to their naturally monogamous mating habits. The research was published in the journal PLOS One. 

Scientists have good reason to keep an eye on these birds. Fifty years ago, the widespread use of DDT nearly wiped out the U.S.’s entire population of peregrine falcons (Falco peregrinus). A ban on the pesticide, combined with aggressive conservation programs, have helped the birds bounce back in a major way. But like so many modern humans, the birds have urbanized. In Illinois alone, almost 90 percent of the peregrine falcon parents build their nests on Chicago’s buildings and bridges. This is a big shift for the falcon pairs, who historically maintained large territories around their cliffside nests. In isolated conditions, monogamy might be a natural choice (where would a bird even find someone else?) but the falcons are isolated no longer. Could living in such close proximity to others encourage falcons to sleep around?

To find out, a team of Chicago-based scientists tracked the nesting behavior of 350 birds at 20 nesting sites in nine Midwestern cities; they also ran DNA tests on the chicks. Three-quarters of the samples came from Chicago, perhaps because members of the Chicago Peregrine Program were already banding and taking blood samples from every falcon they could find. The ankle bands allowed observers to identify the inhabitants of each nest. By testing the birds’ blood, the researchers could figure out if a couple’s babies were 100 percent their own, or if one of the parents had been stepping out. 

Analysis of the DNA results and nest-watching revealed that, almost to a bird, the falcons remained loyal to their partners. Out of 126 baby birds, only 2 were being raised by a bird other than their biological parent, and even that was a special case: The male bird had hooked up with the already-pregnant female after his own mate had died. He was a stepdad, not a cuckold.

Co-author John Bates is associate curator of birds at The Field Museum in Chicago. He says that he and his colleagues were a little surprised by the results. “Each spring this population also has migratory peregrines passing through on their way to all parts of Canada, so we didn’t know what we were going to find,” he said in a press statement, "but it turns out that almost all of the mated pairs in the city remain monogamous through the years.”

Even greater than their loyalty to each other was the falcons’ loyalty to their nesting sites. It makes sense; while a partner might die in a collision with a building or a power line, a safe nesting niche is forever.

The researchers plan to continue keeping an eye on the birds. 

“Whenever you have animals living in habitats that have been influenced by human development, you have to wonder how the animals’ life histories will be altered,” says Bates. “It’s important to do studies like this one to see how birds are adapting to living in human environments, so that we can monitor changes through time.”

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Slow Motion Is the Only Way to Appreciate a Chameleon’s Lightning-Fast Tongue
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From the unusual way they walk, to their ability to change color, the evolutionary adaptations of chameleons are pretty bizarre, and some of them remain mysterious even to scientists. Their super-powered tongues, for instance, can dart out so quickly that the movement can barely be seen with the naked eye. But modern high-speed cameras have enabled researchers at the University of South Dakota to observe this appendage at work like never before. The video below, shared over at The Kid Should See This, includes some of that groundbreaking footage, and it's pretty amazing to watch.

Shooting at 3000 frames per second, the camera was able to capture every split-second aspect of the chameleon's tongue strike. Slowed down, the video allows you to see how every component of the process works in harmony: First, muscles in the lizard’s tongue contract like the string of a bow. Then, when that tension is released, the bony base of the tongue shoots forward, pushing the sticky, elastic part toward the chameleon’s prey.

According to Christopher Anderson, one of the scientists who conducted the high-speed camera research, larger chameleons can catapult their tongues forward at distances of one to two times their body length. For smaller chameleons, this distance can reach up to two and a half times their body length. “Small chameleons need to be able to eat more food for their body size than large chameleons,” he tells bioGraphic in the video, “and so by being able to project their tongues proportionately further than these large species, they basically are opening up additional feeding opportunities to themselves that they wouldn’t have if they had a shorter tongue.”

To see one of nature’s greatest hunting tools in action, check out the full video below.

[h/t The Kid Should See This]

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There May Be an Ancient Reason Why Your Dog Eats Poop
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Dogs aren't known for their picky taste in food, but some pups go beyond the normal trash hunting and start rooting around in poop, whether it be their own or a friend's. Just why dogs exhibit this behavior is a scientific mystery. Only some dogs do it, and researchers aren't quite sure where the impulse comes from. But if your dog is a poop eater, it's nearly impossible to steer them away from their favorite feces.

A new study in the journal Veterinary Medicine and Science, spotted by The Washington Post, presents a new theory for what scientists call "canine conspecific coprophagy," or dogs eating dog poop.

In online surveys about domestic dogs' poop-eating habits completed by thousands of pet owners, the researchers found no link between eating poop and a dog's sex, house training, compulsive behavior, or the style of mothering they received as puppies. However, they did find one common link between the poop eaters. Most tended to eat only poop that was less than two days old. According to their data, 85 percent of poop-eaters only go for the fresh stuff.

That timeline is important because it tracks with the lifespan of parasites. And this led the researchers to the following hypothesis: that eating poop is a holdover behavior from domestic dogs' ancestors, who may have had a decent reason to tuck into their friends' poop.

Since their poop has a high chance of containing intestinal parasites, wolves poop far from their dens. But if a sick wolf doesn't quite make it out of the den in time, they might do their business too close to home. A healthier wolf might eat this poop, but the parasite eggs wouldn't have hatched within the first day or two of the feces being dropped. Thus, the healthy wolf would carry the risk of infection away from the den, depositing the eggs they had consumed away in their own, subsequent bowel movements at an appropriate distance before the eggs had the chance to hatch into larvae and transmit the parasite to the pack.

Domestic dogs may just be enacting this behavior instinctively—only for them, there isn't as much danger of them picking up a parasite at home. However, the theory isn't foolproof. The surveys also found that so-called "greedy eaters" were more likely to eat feces than dogs who aren't quite so intense about food. So yes, it could still be about a poop-loving palate.

But really, it's much more pleasant to think about the behavior as a parasite-protection measure than our best pals foraging for a delicious fecal snack. 

[h/t The Washington Post]

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