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6 Traits Humans Inherited from Monkeys

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Humans didn’t evolve from modern monkeys, but if you trace the branches of our family tree far enough, you’ll realize that we share a common ancestor. Here’s what they left us with.

1. Coccyx, Our Former Tail

Why does falling on your tush hurt so much? Because the tailbone is a remnant of your long-lost tail. (For about four weeks, human embryos have a tail. In rare cases, people are born with them!) The tail disappeared millions of years ago when hominids started walking upright and no longer needed it for balance. However, its absence has left the bottom of our spinal columns exposed. That’s why your coccyx is so easy to bruise and break.

2. Our Complex Hands

Primates are the only mammals with opposable thumbs. Notharctus, a lemur-like monkey that lived 50 million years ago, was the first ape to develop human-like hands: A thumb, long fingers, and nails instead of claws. Why? They were—and still are—perfect for clinging to tree branches!

3. The Ability to See Colors

For millions of years, our ancestors were red-green colorblind. But thanks to receptors called “opsins,” everything went technicolor around 23 million years ago. Most colorblind animals have two sets of opsin genes. Humans, however, have three—and that third gene makes all the difference. Scientists posit that millennia ago, an opsin gene duplicated and mutated and was a huge advantage. (Scientists have confirmed this hypothesis by planting a third opsin gene in the retina of colorblind squirrel monkeys. The experiment gave them human-like color-vision.)

4. Our Crummy Sense of Smell

You can’t have it all. As our sense of vision got better, our sense of smell got worse. We have thousands of genes for smell, but nearly 600 of them don’t work anymore.

5. The Ability to Take a Stroll

For about 365 million years, most animals walked on all fours. But around 4.4 million years ago, a woodland primate called ardipithecus stood up and walked with an awkward wobble. After a couple million years, australopithecus emerged (its most famous member is “Lucy”). Just like humans', its knees bent inward, making walking more natural.

6. Our Bad Backs

Walking came with a cost: it ruined our backs. In order to stay balanced, our ancestors developed an “S-shaped” spine, which—as we all know—leads to kinks, knots, sciatica, and all sorts of pain. But all that aching might be worth it. Standing freed up our hands and gave us a chance to make tools.

Want to learn more about our monkey relatives? Tune in to Your Inner Fish tonight at 10 pm Eastern/9 pm Central on PBS’s Think Wednesday lineup.


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10 Animals with Surprisingly Smart Social Lives
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They may not be able to type out pithy messages in 140 characters or less, and they’re definitely not networking online, but you’ll be surprised at exactly how social certain animals are. Check out these ten animals that might have more of a social network than you.

1. Cows in Cliques Are Smarter Than Lone Bovines

You already know that cows are typically found in herds, but it’s been proven that grouping is actually beneficial to their intelligence. Researcher put calves together and tested them on “reversal learning,” in which they were trained to associate a black or white square with food. Once that had been learned, the researchers switched which color meant food. The clique of calves learned the “reverse” task much faster than the isolated cows. In another test, an unfamiliar object was placed in the pen with a group of cows. The band of bovines grew tired of the new object much faster than the solo cows did, leading researchers to theorize that socially adept cows assimilate better—an important aspect of learning.

2. Female Mule Deer Have Each Other’s Backs

When a female mule deer goes out to graze, she leaves her babies with the other females of the group. If a predator happens by, the other female mule deer will protect all of the nearby fawns, even those belonging to a completely different species of deer, by attacking the bad guy themselves. And you thought you had a good babysitter.

3. Coyotes and Badgers Team Up to Hunt

Sometimes, animals will even cross enemy lines to work toward the greater good. For example, coyotes and badgers tag-team to create a living hell for their prey, eliminating all but the smallest chance for escape. If the prey is above ground, the coyote chases it. If the prey tries to disappear, the badger takes control. It’s a terrible situation for prairie dogs and ground squirrels, but it works out well for both the coyotes and the badgers. Even though they’re actually competing for food, it’s still a win: they’re both able to conserve more energy while taking advantage of each other’s hunting skills.

4. Orcas Teach Their Friends How To Fish

It’s not just old dogs that learn new tricks. Killer whales have been observed picking up new behaviors from one another. Staff at a large sea park observed one of their orcas chewing up the fish chum he was fed. He’d then spit it out onto the surface of the water and wait for a bird to take the bait. While the clueless seagull was snacking, bam—so was the orca. That’s pretty smart, but what’s more impressive is that the whale taught his tricky ways to at least three other orcas in the same enclosure.

5. Rhesus Monkeys Starve Themselves To Protect Another

In 1964, researchers placed a pair of rhesus monkeys in a predicament: If one monkey pulled a chain, he received food to eat, but a shock was delivered to the other monkey at the same time. After he figured out what was happening, the monkey in control of the situation refused to pull the chain for 12 days—he was literally starving to death before he would hurt his fellow test subject again. The lesson? Monkeys have empathy—something even some humans lack.

6. Dolphins Feast Together

In the ocean, up to six dolphins will team up to herd fish together into small groups called “bait balls.” Once the fish are crowded together, the dolphins line up to create a wave that drives the fish in toward shore, making them easy prey—and an easy lunch.

7. Elephants Talk To Each Other (Sometimes In Secret Tones)

Not only do elephants communicate with each other, sometimes they do it in tones humans can’t even hear. After years of observing elephants in the wild, researchers have found that elephants use more than 70 kinds of vocal sounds and 160 visual and tactile signals, expressions, and gestures. They can mean anything from “Let’s go” to “Help, I’m lost.” The latter is often done in a low frequency that will travel for miles through forest, letting the pachyderms connect without alerting other animals to their presence.

8. Cuttlefish Show Their True Colors

It’s pretty normal for us to be selective about which part of ourselves we want to reveal. We show one side to a boss, for instance, and another to a best friend. But cuttlefish can literally split their bodies into different patterns to accomplish different things at the same time. One half of its body may be designed to attract a mate, while the other half is a completely different design to conceal itself from predators. They can even use certain colors to assert dominance in social situations, showing that they’re aware of social hierarchies and structures.

9. Spiders Know That Millions of Legs Are Better Than Eight

What’s more terrifying than the thought of thousands (or millions!) of spiders working together toward one common goal? Not much, but few things are as brilliant, either. Certain species of spiders called “social spiders” act in unison to create massive webs that catch way more prey than one little web would ever catch on its own. In 2007, spiders spun webs that spanned 200 yards in a Texas park. It was later determined that more than 12 families of spiders had participated in building the massive trap.

10. Penguins Get in Sync

Not only do emperor penguins huddle together for warmth, but they also make very specific, synchronized movements that further the effort to retain heat. Roughly every 30 to 60 seconds, all of the penguins in one row of the huddle move anywhere from 2 to 4 inches in the same direction. The penguins in the next row copy the movement soon after, over and over until the whole huddle has completed the tiny maneuver. Researchers theorize that keeping the huddle in constant motion results in a denser (thus warmer) packing, and also keeps the penguins’ blood circulation flowing.

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7 Traits Humans Inherited From Reptiles
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We may not always look it, but humans are repurposed reptiles. Believe it or not, but all of these traits reflect your inner lizard.

1. Our Yolk Sacs

When we’re embryos, a relic of our egg-laying past hangs in the womb with us—a yolk sac. Just like bird and reptile eggs, this sac provides embryos with nutrients. Yolk sacs developed about 300 million years ago when the first amphibians moved onto land. Along with the amniotic sac, it prevented their eggs from drying out.

2. Resilient Skin

It may not look like it, but our skin developed thanks to a reptilian battle with the elements. 300 million years ago, reptiles evolved a new kind of skin to deal with the dry air on land: a watertight barrier of dead skin cells, which rested atop a layer of fresh, living cells. We inherited that same layering system.

3. The Hair On Our Heads (And Elsewhere)

Sorry mammals, but reptiles beat you to the punch and grew hair first. Animals like thrinaxodon—a burrowing reptile that lived 245 million years ago—evolved whiskers to feel around in the dark. Within 20 million years, animals got hairier and hairier, and the first mammals appeared.

4. Ears and Sense of Hearing

Three bones in our middle ear help amplify sound. Amazingly, two of those bones are part of a reptile’s jaw. The fossil record indicates that over 200 million years ago, those two jawbones started receding back into ancient reptiles’ heads. Hadrocodium, a small mouse-like creature that descended from reptiles some 190 million year ago, was one of the first critters to inherit the special three-boned ear.

5. Big Brains

As late reptiles and early mammals developed whiskers and a better sense of hearing, their brains had to process more information. Because of this, their brains started to grow.

6. Our Teeth

Most modern reptiles have long, sharp, peg-shaped chompers (think crocodiles). They don’t have canines—those are strictly found in mammals. But it wasn’t always that way. The dog-like lizard gorgonopsid was one of the first ancient reptiles to flaunt long, saber-toothed canines. By the time the shrew-like tritheldonts appeared 230 million years ago, reptiles were chewing on plants and developing molar-like teeth. Teeth became more complex, setting the stage for humans—and dentists.

7. The Genes That Make Us Us

Of course, we don’t inherit reptile teeth, skin, and bones directly. We simply inherit the genes that make them possible. One gene has a lot to do with all of these transformations—EDA. EDA controls how many teeth you have, what those teeth look like, how hairy you are, and how soft and sweaty your skin is. It’s believed that mutations to EDA in ancient reptiles helped us inherit our body’s current blueprints.

Want to learn more about our reptilian past? Tune in to Your Inner Fish tonight at 10 pm Eastern/9 pm Central on PBS’s Think Wednesday lineup.

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