Ancient Human-Chimp Link Pushed Back Millions of Years

Humanity's genetic split from an ape-like ancestor came about 13 million years ago, far earlier than the long-supposed era of a common ancestor of early humans and apes, suggests a first study of chimp gene mutations.

Along with shining a new genetic light on human origins, the findings published on Thursday in the journal Science point to the role that evolution plays in fostering mutations, some linked to inherited diseases, in our genes.

On the surface, this and other recent studies contradict the general consensus suggested by the fossil record: that the last common ancestor of the two species, a flat-footed ape, lived some seven million years ago.

But both observations could still be true, said paleoanthropologist John Hawks of the University of Wisconsin, Madison, who was not involved in the new study. The ape-like common ancestor species might have endured until 7 to 10 million years ago, long after the genetic split between chimps and humans, he said.

That would largely explain the difference seen between gene-based and fossil-based estimates of the date the species diverged.

"We also don't know if mutation rates varied widely in the ancient past; maybe they were different than now," says study senior author Gil McVean of the United Kingdom's Wellcome Trust Centre for Human Genetics in Oxford.

That could also change estimates of the age of an ancestral genetic split between men and chimps. "That's something only looking at more primates might help tell us," McVean says.

Chimp Mutation Rates

According to the analysis released Thursday, the promiscuity of chimps seems to drive a higher genetic mutation rate in chimp males. Gene mutations in chimp offspring also greatly increases with the age of the ape father. (See video: "Baby Chimp.")

"You really don't want an older chimp as a father," says McVean. "The vast majority of mutations are, at best, neutral," he says, though some can be "very harmful."

Chimps and people share about 99 percent of their DNA, making them our closest living genetic relatives. The rate at which human genes are altered, or mutate, has come under wide study in the past five years. Some studies have raised concerns about older fathers passing disease risks on to their children. But in chimps, the generational mutation rate was uncertain, until now.

"It's one of the fundamental questions," McVean says. Such alterations in genes play a role in inherited diseases and allow for glimpses into our evolutionary history, he says, when compared to other mammals.

In the study, the researchers looked for mutations in the genes of nine chimps: two fathers, two mothers, and five of their offspring.

While overall the chimp genetic mutation rates are the same as human ones, the analysis showed that male chimps contribute three to four more genetic mutations to their offspring than do female chimps, who typically contribute in the range of about 40 mutations per pregnancy. The authors suggest that the much higher rate of cell division in chimp testes (compared to humans) produces more mutations in chimp sperm, and hence passes more mutations on to their offspring.

As the chimp males get older, more cell divisions happen, producing ever more mutations in their sperm. According to the study, chimp fathers contribute two additional genetic mutations for every post-puberty year.

"What they have done is provide us the first direct measure of the mutation rate in another primate," says population geneticist Philip Awadalla of the University of Montreal. "This isn't just a clock for evolutionary time, but something that offers us real insight into evolution."

Sperm Competition

One insight from the study is that the reproductive pattern of chimp males, which frequently mate with multiple females, itself seems to lead to a higher mutation rate in their sperm.

Here's how it happens: Cells increase their numbers by dividing. When cells divide, they provide copies of their genes to their new daughter cells. But each cell division offers an opportunity for a mistake to happen in the gene copying process—a gene mutation.

In the multiple mating milieu of life as a chimp male, a lot of new sperm cells are made and a lot of opportunities crop up for mutations, says geneticist Kári Stefánsson of deCODE Genetics in Reykjavik, Iceland, who led a 2012 study in humans that similarly found higher mutation rates (though not as high as in chimps) in the offspring of older fathers.

"What they are finding here [in the study] seems completely plausible and in line with what you might expect," Stefánsson said. He thought the small sample size, with only two chimp fathers, was a limitation, but "the methods and conclusions seem reasonable," he said.

What's the Difference Between Rabbits and Hares?

Hares and rabbits look similar, and some may hop to the conclusion that they're the same animal.
Not so fast. Our Weird Animal Question of the Week comes from Tristan Ishtar, who asked: "What's the difference between a rabbit and a hare? And is that where 'hare brained' came from?"

The short answer: A lot, and yes—the adjective "harebrained" likely refers to hares' skittish tendencies, especially in captivity.

Hares and rabbits are in the same family, Leporidae, but they're "different species, like sheep and goats are different species," Steven Lukefahr, a geneticist at Texas A&M University in Kingsville, said via email.


Opposites From Birth

Hares are also larger, have longer ears, and are less social than rabbits. The "most profound difference" is seen in baby hares versus baby bunnies, said Philip Stott, a wildlife ecologist at the University of Adelaide in Australia.
First off, a hare's pregnancy lasts 42 days, compared with rabbits' 30-31 days with a bun(ny) in the oven.

Newborn hares, called leverets, are fully developed at birth—furred with open eyes—while newborn rabbits, called kittens or kits, are born undeveloped, with closed eyes, no fur, and an inability to regulate their own temperature, Stott said.

Their nests are also worlds apart—"hares live completely aboveground, lacking the normal burrow or warren system of rabbits," said Michael Sheriff, an ecologist at Penn State in University Park, Pennsylvania.
That's why, as a hare that burrows, "Bugs Bunny is a fraud," Stott joked.

There is an exception to the burrowing-bunny rule—the cottontail, a type of American rabbit that does not burrow.



Are We Fair to the Hare?

As for "harebrained," which means flighty or foolish, Stott suspects it stems from the animals' unease in captivity, where they're prone to spooking at the slightest stimulus (sometimes accidentally causing their own deaths).

Stott, who has tried hand-raising hares, said even those that are bottle-fed from day one never really relax in his company.

The expression "mad as a March hare" is no doubt a reflection on hares' behavior during mating season, which involves leaping into the air, among other antics, Texas A&M's Lukefahr said.

The female hare, called a jill, tests the male, called a jack, by making him give chase over several miles, Stott says. If he catches her, she'll mate with him; if not, "he was poor paternal material anyway," Stott says. (Also see "Wild Romance: Weird Animal Courtship and Mating Rituals.")

But if a female isn't ready to mate with a male who is chasing her, she might stand up and throw a punch right at him—or several.

Life in the Fast Lane

Such a zany courtship is not just about fun—it's also about staying fit, Stott said.

Speed is crucial to hares' survival, especially for species that live on open plains, such as the European hare, which can run at 37 body lengths a second, he said. Cheetahs, he noted, "can only manage 23 body lengths per second."

Those speedy reflexes may be great for avoiding predators, but it makes hares a "poor pet," he said. That's another way they differ from rabbits, which the American Society for the Prevention of Cruelty to Animals describes as "delightful companion animals."

Despite its name, a jackrabbit wouldn't make a good pet, either. It's called that because of its fabulous ears, which reminded its namers of a jackass, but it's not even a rabbit. It's a hare.

Your mind has to be as quick as a bunny to keep these animals straight.

So About That Hairy Guy on the Bus … True-Life Animal Commuters

When one commuter boarded Seattle's D line bus, a fellow rider was astonished at her insistence in finding a window seat.
But Eclipse really needed that window seat. She's a two-year-old black lab-mastiff mix, and she knows to watch for her stop, the dog park, where she meets her owner Jeff Young.

The first time Eclipse took the bus by herself, Young had not yet finished his cigarette when the bus arrived. Rather than wait for her human to finish what he was doing, Eclipse jumped on the bus alone and took a window seat. When the bus stopped at the dog park, she knew to get off.

Young, only a few minutes behind on another bus, met up with Eclipse at the park. Since then, Eclipse has been known to hop on the bus by herself and wait for Young to catch up. Though Young was surprised the first time this happened, it has become part of their routine now. "Probably once a week I get a phone call," Young told KomoNews.com. "'Hi. I have your dog Eclipse here on Third and Bell.' I have to tell them, 'No, she's fine. She knows what she's doing.'"
Eclipse is not the first animal to prefer the comfort of modern public transportation. From birds on a train to goats on a bus—adaptable animals are learning how to get around our expanding cities.

Some are domestic—like cats—but coyotes, monkeys, and other wild species have also found their way onto public transportation.

Pigeon

Birds on a train? Believe it. Pigeons have been known to take the A Line on the New York City subway. According to a 2002 New York Times article, when trains lay over at Far Rockaway Station at the end of the line, pigeons walk onto the trains in search of crumbs.

"But being pigeons, they do not listen for the announcement that the train is leaving, and the doors close on them. They ride generally for one stop, exiting as soon as the doors open again," the Times reported.

But they're not total bird brains: The article reported that a train conductor would see them promptly fly back to the Far Rockaway terminal for more free food.
Domestic Goat

Talk about getting your goat—an owner in Multnomah County, Oregon, was asked to retrieve her pet goat after it escaped and hitched a ride on a Portland school bus in 2008.

The goat was "taken into custody by transit police for lack of proper fare," Portland news station WCSH reported, citing a Multnomah County Animal Control official.

Also in 2008, in Mahoning County, Ohio, news station WFMJ reported on a pet goat that would follow its owner onto a school bus—giving new meaning to the term "new kid on the block."

Coyote

Wily as ever, the coyote has taken to city life, increasingly popping up in urban areas from Chicago to New York.

The predators are versatile—eating everything from shoe leather to fruit—and adaptable, shifting their normally daytime schedules to night to adapt to city life, experts say. (See city pictures.)

In 2002, a coyote hopped on the light rail at the airport in Portland, Oregon, and got comfortable on a seat—but wildlife specialists removed and released it before the train took off.

Even so, the sneaky interloper is forever immortalized in a song: Sleater-Kinney's "Light-Rail Coyote."
Domestic Cat

Famous for their curiosity, cats seem to be the most frequent commuters—especially in England. (Also see "Curious Cat Walks Over Medieval Manuscript.")

Take Macavity, the kitty who would get on a busy bus at the same stop in Walsall every morning, and then jump off at the next stop not far down the road—which just happens to be near a fish-and-chip shop, the Daily Mail reported in 2007.

"I suppose he is the perfect passenger really—he sits quietly, minds his own business, and then gets off," passenger Paul Brennan told the paper.

Then there's Casper the commuter cat, which BBC News reported in 2009 was a regular on a bus near its home in St. Budeaux, England. Sadly, Casper died in 2010 after being hit by a car while crossing the road to board the bus, according to the Daily Mail.

A commuting feline named Dodger liked to sit in laps as he rode the bus around Dorset, England, the Daily Mail reported in 2011. His owner suspects the cat was attracted to the warmth of the bus and recently vacated seats.

Rhesus Monkey

Delhi has a monkey on its back—well, make that several thousand. The Indian city's rhesus monkey population is exploding, bolstered by people who feed the critters, which are considered living representatives of the Hindu god Hanuman, according to a 2012 article in the New York Times.

The emboldened animals have also overrun parts of the city. According to the Times, the animals "treat the Indian Parliament building as a playground, have invaded the prime minister's office and Defense Ministry, sometimes ride buses and subway trains, and chase diplomats from their well-tended gardens."

This monkey videotaped on the Delhi metro looks like a regular commuter, responsibly holding on to the banister and settling into a seat.

Captive Killer Whale Is Ruled to Be Member of Endangered Species

The federal government listed a captive orca at a Miami aquarium as an endangered species on Wednesday, though the new designation doesn't mean the killer whale will be released anytime soon.

Animal activists have fought for years to free the orca, known as Lolita, from the Miami Seaquarium.

In response to a petition filed in 2013 by a consortium of animal rights groups, the National Oceanic and Atmospheric Administration (NOAA) Fisheries ruled Wednesday that "captive animals such as Lolita cannot be assigned separate legal status from their wild counterparts." Lolita came from a specific population of orcas that has been listed as endangered since 2005.

The ruling does not affect other captive orcas in the U.S., says Michael Milstein, a public affairs officer with NOAA Fisheries. Lolita is a special case because she is the only known captive orca in the U.S. from the only population of the species that is considered endangered according to the federal Endangered Species Act.

Wednesday's ruling does not have an immediate effect on Lolita, Milstein said, because "the Endangered Species Act does not prohibit keeping of captive animals." In fact, he said that releasing an orca that has been captive so long could put her and wild animals at risk from disease or aggression.

"Our primary concern is with the safety of wild whales," he said, "in addition to the safety of the captive whale itself."

A spokesperson for the Miami Seaquarium said it was not planning to make any changes.

"Just because she was listed as part of the Endangered Species Act does not mean that she is going anywhere," Seaquarium general manager Andrew Hertz said in a statement. "Lolita is healthy and thriving in her home where she shares her habitat with Pacific white-sided dolphins."
Unique Whale

Lolita was caught in Puget Sound and has been on display at the Miami Seaquarium since 1970. NOAA verified through genetic testing and physical characteristics that the whale originated from the population known as the Southern Resident Killer Whales, which spend much of the year in the inland waters of Washington and British Columbia. That population was classified as endangered in 2005 and is thought to include only about 80 whales.

NOAA Fisheries ruled on Lolita's status after receiving 17,000 comments from the public, most of which supported her inclusion in the endangered species designation, Milstein said.

This isn't the first time a government agency has included captive animals in endangered species designations. The government previously listed sturgeon; the U.S. Fish and Wildlife Service is currently considering the status of captive chimpanzees.
Legal Battle to Come?

Animal rights activists hope the new designation moves Lolita a step closer to release.

"Now that Lolita has been given additional protection from 'harm and harassment' (how else can being confined to the smallest orca tank in North America, denied an orca companion or shelter from the sun, and forced to perform stupid tricks be described?), we'll work to ensure that these protections are enforced and continue to push for her retirement and release," the nonprofit group People for the Ethical Treatment of Animals (PETA) said in a blog post on Wednesday.

A government official familiar with the issue said that PETA may try to use the Endangered Species Act as leverage to sue for the release of Lolita, under the legal precedent that endangered animals cannot be "taken" or "harassed."

Under that reasoning the ruling could be used as leverage to sue for Lolita's release.

"There is now significant precedent behind the idea that captive animals need to be protected just as wild members [of the species] are, and we are going to use everything in our power to make sure that Lolita is protected by the harm and harassment provisions of the Endangered Species Act," said Jared Goodman, PETA's director of animal law.

But the Seaquarium argues that it's in Lolita's best interest to stay there.

"There is no scientific evidence that the 49-year-old post-reproductive Lolita could survive in a sea pen or the open waters of the Pacific Northwest," the Seaquarium's Hertz said in his statement. "And we are not willing to treat her life as an experiment."

Why Do Dogs Watch—and React to—TV?

Dogs watch a Bakers dog food TV advertisement, created especially for canines, in the U.K. in 2012. The one-minute ad contains high-frequency noises that can be heard only by man's best friend.

Our first Weird Animal Question of the Week of 2015 comes to us from our very own photo editor Mallory Benedict, who's curious about why her sister's poodle pays such rapt attention to the television.
"He totally loses it when there's any kind of animal on TV. How does he recognize animals on TV, and why does he have such a strong reaction?" Benedict asked.

Domestic dogs can perceive images on television similarly to the way we do, and they are intelligent enough to recognize onscreen images of animals as they would in real life—even animals they've never seen before—and to recognize TV dog sounds, like barking.

A 2013 study published in the journal Animal Cognition showed that dogs could identify images of other dogs among pictures of humans and other animals, using their visual sense alone. (Also see "OCD Dogs, People Have Similar Brains; Is Your Dog OCD?")

However, there are some differences between ourselves and man's best friend—for one, dogs' eyes register images more quickly than do ours. So older television sets, which show fewer frames per second than modern televisions, would appear to a dog to be flickering like a "1920s movie," said Nicholas Dodman, a veterinary behaviorist at Tufts University, in Massachusetts.

Dogs also have dichromatic vision, which means they see a range of two primary colors, yellow and blue. Human vision is trichromatic, so we see the full range of colors, according to Binghamton University's Ask a Scientist web page.

DogTV, an HDTV cable channel designed for dogs, interests canines because HDTV has a much higher number of frames per second and is specially colored to accommodate dogs' dichromatic vision, said Dodman, who is the channel's chief scientist.
DogTV has modes for relaxation, which shows images like dogs chilling out in a grassy field; stimulation, which depicts scenes like dogs surfing in southern California; and exposure which shows things like a dog reacting to a ringing doorbell and obeying commands to acclimate them to such situations at home.

Doggie Style

Beyond biology, how dogs react to TV—whether it's running around, barking excitedly, or just ignoring it—may come down to personality or breed.

"Different dogs, like people, have different personalities," Dodman said. "Some are territorial, some are not; some like people, some hate people; some are predatory, some aren't; some are pushy, some are shy.

"It takes all types of dogs to make the world go round," he added.

Hearing a barking dog on the set often gets TV-watching dogs excited. (Check out this YouTube video of a German shepherd that barks only when another dog appears on the TV, totally ignoring those boring humans.)

Some dogs not only bark at animals on the screen, but also run behind the TV looking for them.

Others "have been desensitized to television. When they see a dog [on TV], they [may] think, 'Those guys just hang out on the television. They never actually walk around,'" Dodman said.
What breed a dog is may influence its reactions to TV. Hounds, which are driven by smell, aren't as interested in visuals, but herding breeds, such as terriers, may be more stimulated by moving objects they see on the small screen.

Watch Dog

Many of us leave a radio or TV on when we leave the house to keep our dog company, hoping that the sound is more comforting to our pets than silence, Dodman said.

Channels that feature animals might be preferable to news programs, but, like many humans, dogs often just half-watch TV anyway.

"They orient to things they're interested in, look at it for a couple of minutes and go 'hmm, interesting,' and then look away," said Dodman. Even so, "that's better than spinning your wheels all day while your owners are away."

What Makes a Great Sled Dog? Breed, Ambition, Tough Feet

Like many top athletes, Sultana trains hard and has no time for the shenanigans of younger teammates. But you won’t find her in a stadium. Sultana is a sled dog born and bred to work in the punishing winters of Alaska’s Denali National Park and Preserve, and she’s gearing up for another season on the trail.
Right now, sled dogs around the world are busy preparing for the upcoming racing season or for jobs hauling equipment or tourists. Premier events like the Iditarod, the Yukon Quest, or the International Pedigree Stage Stop kick off over the next couple of months, drawing as many as 1,300 dogs and thousands of people to frozen places from Alpine, Wyoming, to Nome, Alaska.

Like Sultana—a trailbreaker who moves supplies for researchers and park staff—the animals competing in these races are a cut above your normal dog.

Contrary to popular belief, Siberian huskies or Alaskan malamutes are not the most popular sled dog breed. That spot belongs to the Alaskan husky, an unofficial breed with a hodge-podge heritage that’s custom-made for the rigors of racing and hauling.

Don’t let their scrappy looks fool you. Generations of breeding have produced animals that love to run, are capable of pulling hundreds of pounds through the snow, and that work together like a well-oiled machine.



The Crucial Ingredients

To breeders, sled dogs’ looks don’t matter as much as performance does. No matter the breed or whether they’re racers or freight-haulers, all these dogs have an insatiable need to go. Howard Thompson, a former racer who now breeds sled dogs near Mondovi, Wisconsin, calls it wanderlust. It’s the idea that “somewhere else is better,” he explains.

A healthy appetite is essential, Thompson adds. Long-distance sled dogs—those competing in events over 300 miles (483 kilometers) long—or freight-haulers like Sultana are out for days or weeks at a time. They can’t be finicky about their meals or prone to digestive issues, he says.

Sled dogs also need tough feet, says Charlotte Mooney, a racer and breeder in West Yellowstone, Montana. Racers can use booties to protect a dog’s paws, but the footwear slows the animals down, she says. Not ideal for sprint races—events less than 30 miles (48 kilometers) long—where dogs run full blast for the duration.



Leaders, Swing Dogs, and Wheel Dogs

Teamwork is also key. Attach a pack of “normal” dogs to a sled, and they’re not likely to go far before chaos ensues.

Lead dogs—the ones out in front—help maintain order. They execute a musher’s commands, set the team’s pace, and ensure everyone’s going in the right direction.

A good lead dog can also think for itself, says Jennifer Raffaeli, manager of Denali’s kennels. They must have the confidence to disobey if a musher’s commands will send them over bad ice or off a cliff. And it helps if they can keep the others in line. Sultana is part of the Denali kennel, and she’s one of Raffaeli’s best leaders.

She’s tough enough to keep the young males focused on work, Raffaeli says, and smart enough to take advantage of inexperienced drivers, or mushers.

When the blue-eyed, eight-year-old Alaskan husky wants a break, she’s been known to stop on a trail, turn around, and come back to the driver while dragging the rest of the team behind her. When Sultana is with an experienced driver, though, she’ll do whatever is asked of her, the kennel manager says.

Backing up lead dogs like Sultana are the swing dogs—positioned right behind the leaders. They help to turn the team left or right. Wheel dogs may be last in line, but they help to steer the sled. The good ones know to go wide on turns to guide the sled around trees and other obstacles, says Thompson.

The dogs in between the swing and wheel positions are called team dogs; they provide the muscle. Their job is to keep pulling until it’s time to stop.



“A Strong Dash of Greyhound”

That willingness to work is a hallmark of sled dogs. But Raffaeli, who breeds all the dogs the park uses, also looks for a sociable personality. The animals interact with visiting tourists during the summer months, so aggressive dogs just won’t do. (Watch how the park raises its puppies.)

A tendency toward aggression is likely one reason why Alaskan malamutes—historically used as sled dogs—have fallen out of favor with many racers, says Thompson, who used to use them. “They have a bad reputation in the sled dog community.”

They’re also slow. “If you want to come in last, race malamutes,” he says.

Siberian huskies, another iconic sledding breed, have also been overtaken. The Alaskan husky, which owes a good portion of its heritage to Siberian huskies and malamutes, are now the “premier” sled dog breed, Thompson explains.

The American Kennel Club doesn’t officially recognize the group, but Alaskan huskies are genetically distinct from purebreds, research has shown.

Breeders looking to boost speed mixed Alaskan huskies with German or English pointers, says Thompson, and added “a strong dash of greyhound.”

The “marathon” runners—including dogs running in the Iditarod—have some border collie, hound, or pointer mixed in, says Stuart Nelson, Jr., head veterinarian for the Iditarod.

Dogs Know What That Smile on Your Face Means

Whether it's with a sympathetic tilt of the head or the excited sweep of a tail, dogs seem to be saying they can sense exactly what we're feeling.
Science is still undecided on the matter, although evidence in favor of the idea is stacking up.
Now, a new study has found that dogs are able to tell the difference between happy and angry human facial expressions.
Biologist Corsin Müller of the University of Veterinary Medicine in Vienna, Austria, and colleagues tested 11 dogs—including border collies, a fox terrier, a golden retriever, a German shepherd, and some mutts—using a touchscreen. The scientists trained the dogs to touch either a happy face or an angry face for a treat.
They presented dogs with either the top half or the bottom half of the faces to ensure the animals weren't just responding to a smile or the baring of teeth. Emotions show on all parts of a human face, not just the mouth, says Müller, whose study was published February 12 in the journal Current Biology.
"If you're angry, a wrinkle between the eyes shows up," he explains. The shape of the eyes can change too.
So if the dogs were truly able to spot an emotion, they should be able to do so regardless of which part of the face they looked at.

Face Time

Once Müller and colleagues trained the dogs, they ran them through choice trials, in which the animals had to pick between strange faces with either happy or angry expressions. The researchers presented the pooches with either the top, bottom, or left half of a face. The scientists chose the left half because previous studies found that dogs prefer to look at the left side of a face.

The pets trained to pick out happy expressions could do so when presented with different halves of a face, as well as when presented with faces the animals hadn't seen before. (Watch a video on working dogs.)
The dogs trained to respond to angry faces were also able to pick out angry expressions among the choices they were asked to make. However, it took them longer to learn their task than the dogs trained on happy faces.
Müller thinks the lag could be because the dogs had negative associations with angry faces. Perhaps angry faces meant a dog wouldn't receive any pats, while happy faces meant a belly rub, he suggests. (See "Dogs Get Jealous, Too.")
Man's Best Friend
Researchers don't yet know whether the dogs' ability to discriminate between the two expressions is because of past experiences or the result of the domestication process.
Whatever the reason, it's not so surprising that dogs can tell facial expressions apart, Müller says. "Because they spend so much time with humans, they have a lot of opportunities to see human expressions." (See "5 Amazing Stories of Devoted Dogs.")
Marc Bekoff, a behavioral ecologist who specializes in canines at the University of Colorado, Boulder, agrees. People and dogs have forged an incredibly close connection over thousands of years together, says Bekoff, who wasn't involved in the study. Along the way, dogs have been bred for certain traits, and "one of the traits would be the ability to read us." (Read "How to Build a Dog" in National Geographic magazine.)
The question now is whether dogs that spend a lot of time with people would be as good at picking up our expressions as dogs without a lot of people experience, Bekoff adds.
Müller plans to pursue that question, and to look at whether domestication played a role in the ability to read human expressions. For that study, the biologist plans to test species such as cats, pigs, and hand-raised wolves.