Science Explains Why Your Lab Is Always Hungry

iStock
iStock

Dogs love food. Some love it more than others, and some of those are Labrador retrievers—the bottomless pits of the canine world. Scientists announced today that they’ve found a gene variant in labs that may explain that constant state of "Please Feed Me." The findings were published last year in the journal Cell Metabolism.

Dog obesity isn't something we talk about a lot, but there sure is a lot of it. In the U.S. and other wealthy countries, between 34 and 59 percent of dogs are overweight. And yes, fat dogs are cute, but they’re also in danger of some serious health problems. Canine obesity can cause heart disease, strain on a dog’s joints, diabetes, and can even shorten a dog’s lifespan.

Some breeds, like black labs, chocolate labs, and golden retrievers, are more obesity-prone than others. This is likely because, like many of us, they are highly motivated by food. Labs’ human companions learn quickly that a treat is the trick to getting their dog to behave. But those treats add up.

The domesticated dog, Canis familiaris, is a single species with a lot of variations. Great Danes and Chihuahuas are both dogs, but their bloodlines, and therefore their genes, are dramatically different. And all those differences within a single species make dog breeds a great resource for scientists studying genetics.

Researchers recruited nearly 400 adult Labrador participants. Of those dogs, 310 were pets recruited through an email invitation from the UK Kennel Club, and 80 were part of an assistance-dog breeding colony. Some of the dogs were fat, while others were not, but all of them were healthy, with no pre-existing conditions.

First, the dogs were weighed. Then the scientists collected drool samples from 33 of the dogs and sequenced the DNA within. The dogs’ owners then completed a survey about their labs’ eating habits.

As relatives, of course, the labs had a great deal of genetic material in common with each other and with other dog breeds. But they also had one gene variant that stood out: the deletion of 14 base pairs from a gene called pro-opiomelanocortin, or POMC. Previous studies of this POMC variant have shown a relationship with appetite and a feeling of fullness.

Each dog could have one copy of the POMC variant, two copies, or none. The more copies a dog had, the fatter and more food-motivated it was. And about 23 percent of labs are carrying at least one copy of the variant.

"People who live with Labradors often say they are obsessed by food, and that would fit with what we know about this genetic change," Cambridge University metabolism expert and lead author Eleanor Raffan said in a press statement.

Her co-author, Stephen O’Rahilly of the Wellcome Trust-Medical Research Council Institute of Science, says these findings have implications beyond kibble. "Common genetic variants affecting the POMC gene are associated with human body weight and there are even some rare obese people who lack a very similar part of the POMC gene to the one that is missing in the dogs. So further research in these obese Labradors may not only help the well-being of companion animals but also have important lessons for human health."

Middle School Student Discovers Megalodon Tooth Fossil on Spring Break

iStock.com/Mark Kostich
iStock.com/Mark Kostich

A few million years ago, the megalodon was the most formidable shark in the sea, with jaws spanning up to 11 feet wide and a stronger bite than a T. Rex. Today the only things left of the supersized sharks are fossils, and a middle school student recently discovered one on a trip to the beach, WECT reports.

Avery Fauth was spending spring break with her family at North Topsail Beach in North Carolina when she noticed something buried in the sand. She dug it up and uncovered a shark tooth the length of her palm. She immediately knew she had found something special, and screamed to get her family's attention.

Her father recognized the megalodon tooth: He had been searching for one for 25 years and had even taught his three daughters to scour the sand for shark teeth whenever they went to the beach. Avery and her sisters found a few more shark teeth that day from great whites, but her megalodon fossil was by far the most impressive treasure from the outing.

Megalodons dominated seas for 20 million years before suddenly dying out 3 million years ago. They grew between 43 and 82 feet long and had teeth that were up to 7.5 inches long—over twice the size of a great white's teeth. They're thought to be the largest sharks that ever lived.

Megalodon teeth have been discovered on every continent except Antarctica, but they're still a rare find. Avery Fauth plans to keep her fossil in a special box at home.

[h/t WECT]

Watch the Denver Zoo’s New Baby Sloth Cuddle Up With Its Mom

Denver Zoo
Denver Zoo

If you’re a sucker for itty, bitty, furry animals, then you’ll want to drop whatever it is you’re doing and check out this video of the Denver Zoo’s newest resident. Uploaded by The Denver Post, the video shows a week-old sloth clinging to its mother, and it’s almost too cute to handle.

The healthy baby, whose name and sex have not yet been determined, was born on April 11 to its proud sloth parents: 23-year-old Charlotte Greenie and 28-year-old Elliot. It also has an older sister, named Baby Ruth, who was born in January of last year. Dad and Baby Ruth are “temporarily off-exhibit” to give mom and her newborn baby the chance to rest and bond in their habitat—an indoor aviary that's part of the zoo's Bird World exhibit.

The baby belongs to one of six species of sloth called the Linne's two-toed sloth, which is native to the rainforests of South America and are not currently considered threatened. Unlike their distant relatives the three-toed sloths, two-toed sloths are mostly nocturnal creatures. They also tend to move faster than their three-clawed counterparts, although fast is putting it generously.

Like many things sloths do, the baby was slow to arrive. Zoo officials predicted that Charlotte would give birth as early as January, but the expected due date may have been a miscalculation.

“Sloth due dates are notoriously challenging to predict because sloths are primarily active at night and we rarely observe their breeding,” the zoo said in a statement. “Our animal care team closely monitored Charlotte for months to ensure that she and the baby were healthy and gaining the appropriate amount of weight.”

The baby is expected to cling to its mother for at least six months. Zoo officials say the best time to visit mom and baby is in the late afternoon, when Charlotte is more likely to be active.

[h/t The Denver Post]

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