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New Study Finds No Link Between Childhood Cat Ownership and Psychosis

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Cats can be manipulative. There's no doubt about that. But are they controlling our minds with their poop? Probably not. Contrary to prior reports, a new study published in the journal Psychological Medicine found that living with a cat in early life did not increase subjects’ risk of psychotic episodes in adolescence.

The premise behind the original idea is less improbable than it sounds. Cats are the host of choice for Toxoplasma gondii, a parasite that has been shown to cause dramatic behavior changes in rodents. (Mice infected with T. gondii lose their fear of cats and become downright friendly, which leads to them getting eaten, which buys the parasite a ticket into its favorite feline hangout.) A few controversial studies have linked cat ownership with schizophrenia and psychotic episodes, but many researchers remain skeptical.

Psychiatrist Francesca Solmi and her co-authors are among those skeptics. They decided to put the theory to the test, focusing specifically on the effects of cat ownership on two vulnerable populations: kids ages 4 to 10 and developing fetuses.

They tapped into a large-scale survey called the Avon Longitudinal Study of Parents and Children (ALSPAC), which has monitored the health of thousands of British kids since the 1990s. For the current study, the researchers compared the mental health of teenagers who had grown up with cats with that of kids in cat-free homes.

At first, it seemed like the psychosis theory might have been at least a little bit correct: The results did suggest a small link between cat ownership and psychotic symptoms at age 13. But once the team adjusted their analysis to consider other variables like family income and crowded home situations, the link disappeared.

"The message for cat owners is clear: there is no evidence that cats pose a risk to children's mental health," Solmi said in a statement. “Previous studies reporting links between cat ownership and psychosis simply failed to adequately control for other possible explanations."

But even if T. gondii has no hand in mental health issues, that doesn’t mean it’s harmless. “There is good evidence that T. gondii exposure during pregnancy can lead to serious birth defects and other health problems in children,” senior author James Kirkbride said. “As such, we recommend that pregnant women should continue to follow advice not to handle soiled cat litter.”

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Why Can Parrots Talk and Other Birds Can't?
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If you've ever seen a pirate movie (or had the privilege of listening to this avian-fronted metal band), you're aware that parrots have the gift of human-sounding gab. Their brains—not their beaks—might be behind the birds' ability to produce mock-human voices, the Sci Show's latest video explains below.

While parrots do have articulate tongues, they also appear to be hardwired to mimic other species, and to create new vocalizations. The only other birds that are capable of vocal learning are hummingbirds and songbirds. While examining the brains of these avians, researchers noted that their brains contain clusters of neurons, which they've dubbed song nuclei. Since other birds don't possess song nuclei, they think that these structures probably play a key role in vocal learning.

Parrots might be better at mimicry than hummingbirds and songbirds thanks to a variation in these neurons: a special shell layer that surrounds each one. Birds with larger shell regions appear to be better at imitating other creatures, although it's still unclear why.

Learn more about parrot speech below (after you're done jamming out to Hatebeak).

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Extinct Penguin Species Was the Size of an Adult Human
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A penguin that waddled across the ice 60 million years ago would have dwarfed the king and emperor penguins of today, according to the Associated Press. As indicated by fossils recently uncovered in New Zealand, the extinct species measured 5 feet 10 inches while swimming, surpassing the height of an average adult man.

The discovery, which the authors say is the most complete skeleton of a penguin this size to date, is laid out in a study recently published in Nature Communications. When standing on land, the penguin would have measured 5 feet 3 inches, still a foot taller than today’s largest penguins at their maximum height. Researchers estimated its weight to have been about 223 pounds.

Kumimanu biceae, a name that comes from Maori words for “monster" and "bird” and the name of one researcher's mother, last walked the Earth between 56 million and 60 million years ago. That puts it among the earliest ancient penguins, which began appearing shortly after large aquatic reptiles—along with the dinosaurs—went extinct, leaving room for flightless carnivorous birds to enter the sea.

The prehistoric penguin was a giant, even compared to other penguin species of the age, but it may not have been the biggest penguin to ever live. A few years ago, paleontologists discovered 40-million-year-old fossils they claimed belonged to a penguin that was 6 feet 5 inches long from beak to tail. But that estimate was based on just a couple bones, so its actual size may have varied.

[h/t AP]

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