Cuckolded Sparrow Fathers Stop Feeding Their Kids

“Predictably Philandering Females Prompt Poor Paternal Provisioning”—that’s the name of a recent report on infidelity in house sparrows. The paper was published in The American Naturalist.

Monogamy means different things to different people—and different animals. House sparrows mate for life, yet years of observation of birds in the wild suggest that they’re also pretty prone to sleeping around. An international team of researchers had a lot of questions about how this works. Are house sparrows really that promiscuous, and, if so, does such behavior pay off? How do the mates of cheating sparrows respond? And how does that affect their kids?

To find out, the researchers set up shop on Lundy Island, an itsy-bitsy spot in the UK’s Bristol Channel. They caught, tagged, and took tiny tissue samples from 200 male birds and 194 females, then released the birds and watched the avian soap opera unfold. Tiny implanted trackers made it possible to tell which bird was which, and when that bird had entered his or her nest.

"Lundy is a unique natural laboratory because it is almost a closed system,” said lead author and Imperial College of London biologist Julia Schroeder in a press statement. “Very few birds leave the island or arrive from the mainland. In the entire 12 years, only four birds immigrated to Lundy, possibly carried by boat."

During that same period, the birds formed 313 pairs and produced 863 broods of baby birds. DNA tests of the birds’ tissue samples, and those of their babies, allowed the researchers to see quite plainly which sparrows were dallying outside their partnerships. A lot of them, it turns out: 38 percent of the broods included offspring from outside partners. Nearly all the couples stayed together once they had bonded, but both male and female birds cheated on their partners.

When those results were matched to video of the sparrows’ behavior, a trend emerged: Cuckolded male sparrows stopped tending to their chicks. This is a big deal for sparrows, a species that depends on care from both parents.

How could the male sparrows tell when their partners had strayed? It wasn’t from looking at the chicks and thinking, “Hey, wait a minute.” The researchers tested this by swapping out a couple’s chicks when they weren’t looking. Dad sparrows couldn’t tell which chicks were theirs, and treated all the little ones interchangeably.

"If chicks were switched into a nest where the female was faithful, then the father at that nest kept up his hard work providing for the chicks, suggesting they have no mechanism, such as smell, to determine which chicks are theirs," Schroeder said.

Instead, the birds are likely relying on context clues. As in: If your mate is going out a lot, and not with you, something might be up. “The males may use cues from the female’s behavior during her fertile period,” Schroeder said, “for example, how long she spends away from the nest.”

Here’s the thing: Animals don’t just sleep around for no reason. Some earlier studies had theorized that cheating might help female sparrows bring fresh genetic material into their nests while maintaining the social stability of a partnership. But if a cuckolded dad starts starving his kids, what’s the benefit?

There may not be one, the researchers say. It’s possible that the sparrows’ cheating hearts are just an evolutionary holdover from the days before the species became monogamous. Or, rather, “monogamous.”

Slow Motion Is the Only Way to Appreciate a Chameleon’s Lightning-Fast Tongue

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]

There May Be an Ancient Reason Why Your Dog Eats Poop

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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