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Pandiyan V via Flickr // CC BY-NC 2.0
Pandiyan V via Flickr // CC BY-NC 2.0

Crows and Ravens Are Experts in Self-Restraint

Pandiyan V via Flickr // CC BY-NC 2.0
Pandiyan V via Flickr // CC BY-NC 2.0

We’ve written before about how crows are thrifty, vengeful bird-geniuses. One study published in the journal Animal Behavior shows they also may be masters of self-control. 

Researchers tested the delayed-gratification capacities of seven crows and five ravens by first offering them morsels of food. The scientists then closed their feeding hands while presenting a different piece of food in the other hand. If the birds could wait out delays ranging from a few seconds to 10 minutes, the scientists then would open their empty hands so the crows could return the food in exchange for a better reward.

In a second experiment, researchers would offer the animals increasing portions of food at fixed intervals. They were free to take the food at any time, but if they did that meant the treats would stop flowing. 

The studies showed that the birds were willing to exercise self-control when a tastier treat was on the line, but not for more of the same thing. Crows who had already had a piece of bread stuck around for pieces of sausage or fried pork fat, but if it was more bread that was being offered it wasn’t worth the effort.

A similar study was conducted at Stanford in 1972—the major difference being the subjects were children instead of crows. Researchers offered two marshmallows to more than 600 children between the ages of four and five. The one condition was that the children would be left in a room alone with the first marshmallow for 15 minutes, and in order to get the second they had to wait to eat it. 

Only a third of the subjects were able to wait the full 15 minutes, and a fraction of them devoured the marshmallow as soon as they were left alone. A follow-up study showed that the kids who waited got higher SAT scores later in life. Humans, it seems, could learn a thing or two from crows, especially when they're thinking about ordering that second appetizer. 

[h/t: Scientific American]

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Animals
10 Notable Gestation Periods in the Animal Kingdom
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The gestation periods of the animal kingdom are varied and fascinating. Some clock in at just a few weeks, making any human green with envy, while others can last more than a year. Here are 10 notable gestation times for animals around the globe. The lesson? Be thankful that you’re not a pregnant elephant.

1. ELEPHANTS: 640-660 DAYS

Elephants are pregnant for a long time. Like really, really long. At an average of 95 weeks, the gestation period is more than double the length of a human pregnancy, so it shouldn't come as a shock that female elephants don't often have more than four offspring during their lifetimes. Who has the time?

2. HIPPOS: 8 MONTHS

A photo of a mother hippo and her baby in Uganda

Yes, it takes less time to make a hippopotamus than it takes to make a human.

3. GIRAFFE: 14-15 MONTHS

Baby giraffes can weigh more than 150 pounds and can be around 6 feet tall. Another fascinating tidbit: giraffes give birth standing up, so it's pretty normal for a baby to fall 6 feet to the ground.

4. KILLER WHALE: 17 MONTHS

There’s a reason for the long wait: after that 17 months, Baby Shamu emerges weighing anywhere from 265 to 353 pounds and measuring about 8.5 feet long. Yikes.

5. OPOSSUM: 12-13 DAYS

A baby opossum wrapped up in a blanket

Blink and you'll miss it: This is the shortest gestation period of any mammal in North America. But since the lifespan of an opossum is only two to four years, it makes sense.

6. GERBILS: 25 DAYS

Hey, they get off pretty easy.

7. GORILLAS: 8.5 MONTHS

It's not a huge surprise that their gestational periods are pretty similar to ours, right?

8. BLACK BEAR: 220 DAYS

A pair of black bear cubs

Also less than a human. Interestingly, cubs might only be 6 to 8 inches in length at birth and are completely hairless. 

9. PORCUPINE: 112 DAYS

This is the longest gestation period of any rodent. Thankfully for the mother, porcupine babies (a.k.a. porcupettes) are actually born with soft quills, and it's not until after birth that they harden up.

10. WALRUS: 15 MONTHS

Baby walruses? Kind of adorable. They certainly take their sweet time coming out, though.

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Goldfish Can Get Depressed, Too
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Don’t believe what Pixar is trying to sell you: Fish are not exactly brimming with personality. In aquariums, they tend to swim in circles, sucking up fragments of food and ducking around miniature treasure chests. To a layperson, fish don’t appear to possess concepts of happy, or sad, or anything in between—they just seem to exist.

This, researchers say, is not quite accurate. Speaking with The New York Times, Julian Pittman, a professor at the Department of Biological and Environmental Sciences at Troy University, says that fish not only suffer from depression, they can be easily diagnosed. Zebrafish dropped into a new tank who linger at the bottom are probably sad; those who enthusiastically explore the upper half are not.

In Pittman’s studies, fish depression can be induced by getting them “drunk” on ethanol, then cutting off the supply, resulting in withdrawal. These fish mope around the tank floor until they’re given antidepressants, at which point they begin happily swimming near the surface again.

It’s impossible to correlate fish depression with that of a human, but Pittman believes the symptoms in fish—losing interest in exploring and eating—makes them viable candidates for exploring neuroscience and perhaps drawing conclusions that will be beneficial in the land-dwelling population.

In the meantime, you can help ward off fish blues by keeping them busy—having obstacles to swim through and intriguing areas of a tank to explore. Just like humans, staying active and engaged can boost their mental health.

[h/t The New York Times]

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