Chapter 6. Evolution of the Brain and Behavior
Follow us on Facebook and Twitter, or subscribe to our mailing list, to receive news updates. Learn more.
By Emily Underwood When you let forth a big, embarrassing yawn during a boring lecture or concert, you succumb to a reflex so universal among animals that Charles Darwin mentioned it in his field notes. “Seeing a dog & horse & man yawn, makes me feel how much all animals are built on one structure,” he wrote in 1838. Scientists, however, still don’t agree on why we yawn or where it came from. So in a new study, researchers watched YouTube videos of 29 different yawning mammals, including mice, kittens, foxes, hedgehogs, walruses, elephants, and humans. (Here is a particularly cute montage used in the study.) They discovered a pattern: Small-brained animals with fewer neurons in the wrinkly outer layer of the brain, called the cortex, had shorter yawns than large-brained animals with more cortical neurons, the scientists report today in Biology Letters. Primates tended to yawn longer than nonprimates, and humans, with about 12,000 million cortical neurons, had the longest average yawn, lasting a little more than 6 seconds. African elephants, whose brains are close to the same weight as humans’ and have a similar number of cortical neurons, lasted about 6 seconds. The yawns of tiny-brained mice, in contrast, were less than 1.5 seconds in duration. The study lends support to a long-held hypothesis that yawning has an important physiological effect, such as increasing blood flood to the brain and cooling it down, the scientists say. © 2016 American Association for the Advancement of Science.
Emily Underwood To human observers, bumblebees sipping nectar from flowers appear cheerful. It turns out that the insects may actually enjoy their work. A new study suggests that bees experience a “happy” buzz after receiving a sugary snack, although it’s probably not the same joy that humans experience chomping on a candy bar. Scientists can’t ask bees or other animals how they feel. Instead, researchers must look for signs of positive or negative emotions in an animal’s decision making or behavior, says Clint Perry, a neuroethologist at Queen Mary University of London. In one such study, for example, scientists shook bees vigorously in a machine for 60 seconds — hard enough to annoy, but not hard enough to cause injury — and found that stressed bees made more pessimistic decisions while foraging for food. The new study, published in the Sept. 30 Science, is the first to look for signs of positive bias in bee decision making, Perry says. His team trained 35 bees to navigate a small arena connected to a plastic tunnel. When the tunnel was marked with a blue flower, the bees learned that a tasty vial of sugar water awaited them at its end. When a green flower was present, there was no reward. Once the bees learned the difference, the scientists threw the bees a curveball: Rather than being blue or green, the flower had a confusing blue-green hue. Faced with the ambiguous blossom, the bees appeared to dither, meandering around for roughly 100 seconds before deciding whether to enter the tunnel. Some didn’t enter at all. But when the scientists gave half the bees a treat — a drop of concentrated sugar water — that group spent just 50 seconds circling the entrance before deciding to check it out. Overall, the two groups flew roughly the same distances at the same speeds, suggesting that the group that had gotten a treat first had not simply experienced a boost in energy from the sugar, but were in a more positive, optimistic state, Perry says. |© Society for Science & the Public 2000 - 2016.
Carl Zimmer Modern humans evolved in Africa roughly 200,000 years ago. But how did our species go on to populate the rest of the globe? The question, one of the biggest in studies of human evolution, has intrigued scientists for decades. In a series of extraordinary genetic analyses published on Wednesday, researchers believe they have found an answer. In the journal Nature, three separate teams of geneticists survey DNA collected from cultures around the globe, many for the first time, and conclude that all non-Africans today trace their ancestry to a single population emerging from Africa between 50,000 and 80,000 years ago. “I think all three studies are basically saying the same thing,” said Joshua M. Akey of the University of Washington, who wrote a commentary accompanying the new work. “We know there were multiple dispersals out of Africa, but we can trace our ancestry back to a single one.” The three teams sequenced the genomes of 787 people, obtaining highly detailed scans of each. The genomes were drawn from people in hundreds of indigenous populations: Basques, African pygmies, Mayans, Bedouins, Sherpas and Cree Indians, to name just a few. The DNA of indigenous populations is essential to understanding human history, many geneticists believe. Yet until now scientists have sequenced entire genomes from very few people outside population centers like Europe and China. © 2016 The New York Times Company
Link ID: 22682 - Posted: 09.22.2016
By Brian Owens It’s certainly something to crow about. New Caledonian crows are known for their ingenious use of tools to get at hard-to-reach food. Now it turns out that their Hawaiian cousins are adept tool-users as well. Christian Rutz at the University of St Andrews in the UK has spent 10 years studying the New Caledonian crow and wondered whether any other crow species are disposed to use tools. So he looked for crows that have similar features to the New Caledonian crow – a straight bill and large, mobile eyes that allow it to manipulate tools, much as archaeologists use opposable thumbs as an evolutionary signature for tool use in early humans. “The Hawaiian crow really stood out,” he says. “They look quite similar.” Hawaiian crows are extinct in the wild, but 109 birds still live in two captive breeding facilities in Hawaii. That meant Rutz was able to test pretty much every member of the species. He stuffed tasty morsels into a variety of holes and crevices in a log, and gave the birds a variety of sticks to see if they would use them to dig out the food. Almost all of them did, and most extracted the food in less than a minute, faster than the researchers themselves could. “It’s mind-blowing,” says Rutz. “They’re very good at getting the tool in the right position, and if they’re not happy with it they’ll modify it or make their own.” © Copyright Reed Business Information Ltd.
By JAMES GORMAN Who’s a good dog? Well, that depends on whom you’re asking, of course. But new research suggests that the next time you look at your pup, whether Maltese or mastiff, you might want to choose your words carefully. “Both what we say and how we say it matters to dogs,” said Attila Andics, a research fellow at Eotvos Lorand University in Budapest. Dr. Andics, who studies language and behavior in dogs and humans, along with Adam Miklosi and several other colleagues, reported in a paper to be published in this week’s issue of the journal Science that different parts of dogs’ brains respond to the meaning of a word, and to how the word is said, much as human brains do. Photo A dog waiting for its brain activity to be measured in a magnetic resonance imaging machine for research reported in the journal Science. Credit Enik Kubinyi As with people’s brains, parts of dogs’ left hemisphere react to meaning and parts of the right hemisphere to intonation — the emotional content of a sound. And, perhaps most interesting to dog owners, only a word of praise said in a positive tone really made the reward system of a dog’s brain light up. The experiment itself was something of an achievement. Dr. Andics and his colleagues trained dogs to enter a magnetic resonance imaging machine and lie in a harness while the machine recorded their brain activity. A trainer spoke words in Hungarian — common words of praise used by dog owners like “good boy,” “super” and “well done.” The trainer also tried neutral words like “however” and “nevertheless.” Both the praise words and neutral words were offered in positive and neutral tones. The positive words spoken in a positive tone prompted strong activity in the brain’s reward centers. All the other conditions resulted in significantly less action, and all at the same level. © 2016 The New York Times Company
Laurel Hamers The brains of human ancestors didn’t just grow bigger over evolutionary time. They also amped up their metabolism, demanding more energy for a given volume, a new study suggests. Those increased energy demands might reflect changes in brain structure and organization as cognitive abilities increased, says physiologist Roger Seymour of the University of Adelaide in Australia, a coauthor of the report, published online August 31 in Royal Society Open Science. Blood vessels passing through bones leave behind holes in skulls; bigger holes correspond to bigger blood vessels. And since larger vessels carry more blood, scientists can use hole size to estimate blood flow in extinct hominids’ brains. Blood flow in turn indicates how much energy the brain consumed. (In modern humans, the brain eats up 20 to 25 percent of the energy the body generates when at rest.) Seymour and colleagues focused on the carotid arteries, the vessels that deliver the bulk of the brain’s blood. The team looked at nearly three dozen skulls from 12 hominid species from the last 3 million years, including Australopithecus africanus, Homo neanderthalensis and Homo erectus. In each, the researchers compared the brain’s overall volume with the diameter of the carotid artery’s tiny entrance hole at the base of the skull. “We expected to find that the rate of blood flow was proportional to the brain size,” Seymour says. “But we found that wasn’t the case.” Instead, bigger brains required more blood flow per unit volume than smaller brains. |© Society for Science & the Public 2000 - 2016.
Link ID: 22616 - Posted: 08.31.2016
By Lydia Pyne | On August 3, 1908, the first near-complete Neanderthal skeleton was discovered in a cave near the village of La Chapelle-aux-Saints in south central France, during a survey of the region’s Paleolithic archaeological sites. For decades prior, prehistorians had collected bits and pieces of curious but not-quite-human fossils from museums and excavations alike—the odd skull here, a scrap of tooth there. In 1863, the mélange of bones was finally given its own species designation, Homo neanderthalensis. Forty-five years later, the La Chapelle discovery was the first Neanderthal specimen found in an original archaeological context and the first to be expertly excavated and carefully studied. Because the body was arranged in a flexed, fetal position and carefully placed in the floor of the cave, excavators argued that fossil—nicknamed the Old Man—had been purposefully buried by his Neanderthal contemporaries. More than any other single individual, the Old Man of La Chapelle has shaped the way that science and popular culture have thought about Neanderthals. But why? What is it about this Neanderthal’s story that is so special? In short, the Old Man was the right fossil found at the right time. He was—and still is—offered as a key bit of evidence in debates about evolution and human origins. He quickly became a scientific touchstone, an archetype for how science and popular culture create celebrity fossils. I explore the stories of similarly spectacular paleoanthropological finds in my new book Seven Skeletons: The Evolution of the World’s Most Famous Human Fossils. © 1986-2016 The Scientist
Link ID: 22585 - Posted: 08.23.2016
by Helen Thompson Some guys really know how to kill a moment. Among Mediterranean fish called ocellated wrasse (Symphodus ocellatus), single males sneak up on mating pairs in their nest and release a flood of sperm in an effort to fertilize some of the female’s eggs. But female fish may safeguard against such skullduggery through their ovarian fluid, gooey film that covers fish eggs. Suzanne Alonzo, a biologist at Yale University, and her colleagues exposed sperm from both types of males to ovarian fluid from female ocellated wrasse in the lab. Nesting males release speedier sperm in lower numbers (about a million per spawn), while sneaking males release a lot of slower sperm (about four million per spawn). Experiments showed that ovarian fluid enhanced sperm velocity and motility and favored speed over volume. Thus, the fluid gives a female’s chosen mate an edge in the race to the egg, the researchers report August 16 in Nature Communications. While methods to thwart unwanted sperm are common in species that fertilize within the body, evidence from Chinook salmon previously hinted that external fertilizers don’t have that luxury. However, these new results suggest otherwise: Some female fish retain a level of control over who fathers their offspring even after laying their eggs. Male ocellated wrasse come in three varieties: sneaky males (shown) that surprise mating pairs with sperm but don’t help raise offspring; nesting males that build algae nests and court females; and satellite males, which protect nests from sneakers but staying out of parenting. |© Society for Science & the Public 2000 - 2016
By Virginia Morell Fourteen years ago, a bird named Betty stunned scientists with her humanlike ability to invent and use tools. Captured from the wild and shown a tiny basket of meat trapped in a plastic tube, the New Caledonian crow bent a straight piece of wire into a hook and retrieved the food. Researchers hailed the observation as evidence that these crows could invent new tools on the fly—a sign of complex, abstract thought that became regarded as one of the best demonstrations of this ability in an animal other than a human. But a new study casts doubt on at least some of Betty’s supposed intuition. Scientists have long agreed that New Caledonian crows (Corvus moneduloides), which are found only on the South Pacific island of the same name, are accomplished toolmakers. At the time of Betty’s feat, researchers knew that in the wild these crows could shape either stiff or flexible twigs into tools with a tiny, barblike hook at one end, which they used to lever grubs from rotting logs. They also make rakelike tools from the leaves of the screw pine (Pandanus) tree. But Betty appeared to take things to the next level. Not only did she fashion a hook from a material she’d never previously encountered—a behavior not observed in the wild—she seemed to know she needed this specific shape to solve her particular puzzle. © 2016 American Association for the Advancement of Science. A
Amy McDermott You’ve got to see it to be it. A heightened sense of red color vision arose in ancient reptiles before bright red skin, scales and feathers, a new study suggests. The finding bolsters evidence that dinosaurs probably saw red and perhaps displayed red color. The new finding, published in the Aug. 17 Proceedings of the Royal Society B, rests on the discovery that birds and turtles share a gene used both for red vision and red coloration. More bird and turtle species use the gene, called CYP2J19, for vision than for coloration, however, suggesting that its first job was in sight. “We have this single gene that has two very different functions,” says evolutionary biologist Nicholas Mundy of the University of Cambridge. Mundy’s team wondered which function came first: the red vision or the ornamentation. In evolution, what an animal can see is often linked with what others can display, says paleontologist Martin Sander of the University of Bonn in Germany, who did not work on the new study. “We’re always getting at color from these two sides,” he says, because the point of seeing a strong color is often reading visual signals. Scientists already knew that birds use CYP2J19 for vision and color. In bird eyes, the gene contains instructions for making bright red oil droplets that filter red light. Other forms of red color vision evolved earlier in other animals, but this form allows birds to see more shades of red than humans can. Elsewhere in the body, the same gene can code for pigments that stain feathers red. Turtles are the only other land vertebrates with bright red oil droplets in their eyes. But scientists weren’t sure if the same gene was responsible, Mundy says. |© Society for Science & the Public 2000 - 2016
By TATIANA SCHLOSSBERG Need a laugh? Get online and take a look at videos of baby Japanese macaques smiling as they sleep. Their faces twitch, usually just on one side and for less than a second. A lip curls, a nose wrinkles — as if they were hairy, wry elves. Newborn Japanese macaques -- like humans and chimpanzees -- were found to make facial expressions called "spontaneous smiles." Watch the full video. Credit Kyoto University Primate Research Institute Maybe you don’t laugh, maybe you just smile back — O.K., fine. But you may owe that smile to the human version of this infant’s facial spasm. Some scientists suspect spontaneous smiles in these monkeys echo the development of our own expressions. Scientists from the Primate Research Institute at Kyoto University in Japan have observed these spontaneous smiles in Japanese macaques for the first time, according to a new study published in the journal Primates. Spontaneous smiles have previously been observed in infant humans and chimpanzees, but this is the first time they have been seen in another primate species. The scientists watched seven macaque monkeys for an average of 44 minutes, during which the monkeys happened to fall asleep. During REM sleep, each of the monkeys spontaneously smiled at least once, for a little less than a second on average. All told, the seven monkeys smiled 58 times, mostly on the left side of their faces. Human and macaque infants alike primarily smile on one side of their faces. But after two months, human babies begin to smile bilaterally. Around the same time, they also begin to offer up “social smiles,” indicating to others a feeling of happiness. According to the study, scientists think that the earliest spontaneous smiles are key to the development of the zygomaticus major muscle, which is responsible for moving your lips up or to the side, allowing you to smile, among other things. Spontaneous smiles in these monkeys echo the development of our own expressions. Watch the full video.
Helen Thompson A roughly 27-million-year-old fossilized skull echoes growing evidence that ancient whales could navigate using high-frequency sound. Discovered over a decade ago in a drainage ditch by an amateur fossil hunter on the South Carolina coast, the skull belongs to an early toothed whale. The fossil is so well-preserved that it includes rare inner ear bones similar to those found in modern whales and dolphins. Inspired by the Latin for “echo hunter,” scientists have now named the ancient whale Echovenator sandersi. “It suggests that the earliest toothed whales could hear high-frequency sounds,” which is essential for echolocation, says Morgan Churchill, an anatomist at the New York Institute of Technology in Old Westbury. Churchill and his colleagues describe the specimen online August 4 in Current Biology. Modern whales are divided on the sound spectrum. Toothed whales, such as orcas and porpoises, use high-frequency clicking sounds to sense predators and prey. Filter-feeding baleen whales, on the other hand, use low-frequency sound for long-distance communication. Around 35 million years ago, the two groups split, and E. sandersi emerged soon after. CT scans show that E. sandersi had a few features indicative of ultrasonic hearing in modern whales and dolphins. Most importantly, it had a spiraling inner ear bone with wide curves and a long bony support structure, both of which allow a greater sensitivity to higher-frequency sound. A small nerve canal probably transmitted sound signals to the brain. © Society for Science & the Public 2000 - 2016. All rights reserved.
By Alice Klein Rise and shine! Neuronal switches have been discovered that can suddenly rouse flies from slumber – or send them into a doze. There are several parallels between sleep in flies and mammals, making fruit flies a good choice for investigating how we sleep. One way to do this is to use optogenetics to activate specific neurons to see what they do. This works by using light to turn on cells genetically modified to respond to certain wavelengths. Gero Miesenböck at the University of Oxford and his team have discovered how to wake flies up. Using light as the trigger the team stimulated neurons that release a molecule called dopamine. The dopamine then switched off sleep-promoting neurons in what’s called the dorsal fan-shaped body, waking the flies. Meanwhile, Fang Guo at Brandeis University in Waltham, Massachusetts, and his team have found that activating neurons that form part of a fly’s internal clock will send it to sleep. When stimulated, these neurons released glutamate, which turned off activity-promoting neurons in the master pacemaker area of the brain. While human and fly brains are obviously very different in structure, being asleep or awake are similar states regardless of the kind of brain an animal has, says Bruno van Swinderen at the University of Queensland, Australia. © Copyright Reed Business Information Ltd.
By Sarah Kaplan Sleep just doesn't make sense. "Think about it," said Gero Miesenböck, a neuroscientist at the University of Oxford. "We do it. Every animal with a brain does it. But obviously it has considerable risks." Sleeping animals are incredibly vulnerable to attacks, with no obvious benefit to make up for it — at best, they waste precious hours that could be used finding food or seducing a mate; at worst, they could get eaten. "If evolution had managed to invent an animal that doesn’t need to sleep ... the selective advantage for it would be immense," Miesenböck said. "The fact that no such animal exists indicates that sleep is really vital, but we don't know why." But Miesenböck is part of team of sleep researchers who believe they are inching closer to to an answer. In a paper published in the journal Nature on Wednesday, they describe a cluster of two dozen brain cells in fruit flies that operate as a homeostatic sleep switch, turning on when the body needs rest and off again when it's time to wake up. "It's like a thermostat," Miesenböck said of the switch, "But instead of responding to temperature it responds to something else." If he and his colleagues could find out what that "something" is, "we might have the answer to the mystery of sleep."
by Helen Thompson Pinky and The Brain's smarts might not be so far-fetched. Some mice are quicker on the uptake than others. While it might not lead to world domination, wits have their upside: a better shot at staying alive. Biologists Audrey Maille and Carsten Schradin of the University of Strasbourg in France tested reaction time and spatial memory in 90 African striped mice (Rhabdomys pumilio) over the course of a summer. For this particular wild rodent, surviving harsh summer droughts means making it to mating season in the early fall. The team saw some overall trends: Females were more likely to survive if they had quick reflexes, and males were more likely to survive if they had good spatial memory. Cognitive traits like reacting quickly and remembering the best places to hide are key to eluding predators during these tough times but may come with trade-offs for males and females. The results show that an individual mouse’s cognitive strengths are linked to its survival odds, suggesting that the pressure to survive can shape basic cognition, Maille and Schradin write August 3 in Biology Letters. |© Society for Science & the Public 2000 - 2016
By Alice Klein The debate has finally been put to bed. Wearable brainwave recorders confirm that birds do indeed sleep while flying, but only for brief periods and usually with one half of their brain. We know several bird species can travel vast distances non-stop, prompting speculation that they must nap mid-flight. Great frigatebirds, for example, can fly continuously for up to two months. On the other hand, the male sandpiper, for one, can largely forgo sleep during the breeding season, hinting that it may also be possible for birds to stay awake during prolonged trips. To settle this question, Niels Rattenborg at the Max Planck Institute for Ornithology in Seewiesen, Germany, and his colleagues fitted small brain activity monitors and movement trackers to 14 great frigatebirds. During long flights, the birds slept for an average of 41 minutes per day, in short episodes of about 12 seconds each. By contrast, they slept for more than 12 hours per day on land. Frigatebirds in flight tend to use one hemisphere at a time to sleep, as do ducks and dolphins, but sometimes they used both. “Some people thought that all their sleep would have to be unihemispheric otherwise they would drop from the sky,” says Rattenborg. “But that’s not the case – they can sleep with both hemispheres and they just continue soaring.” Sleep typically took place as the birds were circling in rising air currents, when they did not need to flap their wings. © Copyright Reed Business Information Ltd.
By Libby Copeland Don’t get him wrong: Dean Burnett loves the brain as much as the next neuroscientist. But if he’s being honest, it’s “really quite rubbish in a lot of ways,” he says. In his new book, Idiot Brain, Burnett aims to take our most prized organ down a peg or two. Burnett is most fascinated by the brain’s tendency to trip us up when it’s just trying to help. His book explores many of these quirks: How we edit our own memories to make ourselves look better without knowing it; how anger persuades us we can take on a bully twice our size; and what may cause us to feel like we’re falling and jerk awake just as we’re falling asleep. (It could have something to do with our ancestors sleeping in trees.) We caught up with Burnett, who is also a science blogger for The Guardian and a stand-up comic, to ask him some of our everyday questions and frustrations with neuroscience. Why is it that we get motion sickness when we’re traveling in a plane or a car? We haven’t evolved, obviously, to ride in vehicles; that’s a very new thing in evolutionary terms. So the main theory as to why we get motion sickness is that it’s essentially a conflict in the senses that are being relayed to the subcortical part of the brain where the senses are integrated together. The body and the muscles are saying we are still. Your eyes are saying the environment is still. The balance sense in the ears are detecting movement. The brain is getting conflicting messages from the fundamental senses, and in evolutionary terms there’s only one thing that can cause that, which is a neurotoxin. And as a result the brain thinks it’s been poisoned and what do you do when you’ve been poisoned? Throw up.
Link ID: 22508 - Posted: 08.03.2016
By Katherine S. Pollard When the first human genome sequence was published in 2001,1 I was a graduate student working as the statistics expert on a team of scientists. Hailing from academia and biotechnology, we aimed to discover differences in gene expression levels between tumors and healthy cells. Like many others, I had high hopes for what we could do with this enormous text file of more than 3 billion As, Cs, Ts, and Gs. Ambitious visions of a precise wiring diagram for human cells and imminent cures for disease were commonplace among my classmates and professors. But I was most excited about a different use of the data, and I found myself counting the months until the genome of a chimpanzee would be sequenced. Chimps are our closest living relatives on the tree of life. While their biology is largely similar to ours, we have many striking differences, ranging from digestive enzymes to spoken language. Humans also suffer from an array of diseases that do not afflict chimpanzees or are less severe in them, including autism, schizophrenia, Alzheimer’s disease, diabetes, atherosclerosis, AIDS, rheumatoid arthritis, and certain cancers. I had long been fascinated with hominin fossils and the way the bones morphed into different forms over evolutionary time. But those skeletons cannot tell us much about the history of our immune system or our cognitive abilities. So I started brainstorming about how to extend the statistical approaches we were using for cancer research to compare human and chimpanzee DNA. My immodest goal was to identify the genetic basis for all the traits that make humans unique. © 1986-2016 The Scientist
By NICHOLAS ST. FLEUR Orangutan hear, orangutan do. Researchers at the Indianapolis Zoo observed an orangutan mimic the pitch and tone of human sounds, for the first time. The finding, which was published Wednesday, provides insight into the evolutionary origin of human speech, the team said. “It really redefines for us what we know about the capabilities of orangutans,” said Rob Shumaker, director of the zoo and an author on the paper. “What we have to consider now is the possibility that the origins of spoken language are not exclusively human, and that they may have come from great apes.” Rocky, an 11-year-old orangutan at the zoo, has a special ability. He can make sounds using his vocal folds, or voice box, that resemble the vowel “A,” and sound like “Ah.” The noises, or “wookies” as the researchers called them, are variations of the same vocalization. Sometimes the great ape would say high-pitched “wookies” and sometimes he would say his “Ahs” in a lower pitch. The researchers note that the sounds are specific to Rocky and ones that he used everyday. No other orangutan, captive or wild, made these noises. Rocky, who had never lived in the rain forest, apparently learned the skill during his time as an entertainment orangutan before coming to the zoo. He was at one point the most seen orangutan in movies and commercials, according to the zoo. The researchers said that Rocky’s grunts show that great apes have the capacity to learn to control their muscles to deliberately alter their sounds in a “conversational” manner. The findings, which were published in the journal Scientific Reports, challenge the notion that orangutans — an endangered species that shares about 97 percent of it DNA with humans — make noises simply in response to something, sort of like how you might scream when you place your hand on a hot stove. © 2016 The New York Times Company
An orangutan copying sounds made by researchers offers new clues to how human speech evolved, scientists say. Rocky mimicked more than 500 vowel-like noises, suggesting an ability to control his voice and make new sounds. It had been thought these great apes were unable to do this and, since human speech is a learned behaviour, it could not have originated from them. Study lead Dr Adriano Lameira said this "notion" could now be thrown "into the trash can". Dr Lameira, who conducted the research at Amsterdam University prior to joining Durham University, said Rocky's responses had been "extremely accurate". The team wanted to make sure the ape produced a new call, rather than adapting a "normal orangutan call with a personal twist" or matching sounds randomly or by coincidence, he said. The new evidence sets the "start line for scientific inquiry at a higher level", he said. "Ultimately, we should be now in a better position to think of how the different pieces of the puzzle of speech evolution fit together." The calls Rocky made were different from those collected in a large database of recordings, showing he was able to learn and produce new sounds rather than just match those already in his "vocabulary". In a previous study Dr Lameira found a female orangutan at Cologne Zoo in Germany was able to make sounds with a similar pace and rhythm to human speech. Researchers were "astounded" by Tilda's vocal skills but could not prove they had been learned, he said. However, the fact that "other orangutans seem to be exhibiting equivalent vocal skills shows that Rocky is not a bizarre or abnormal individual", Dr Lameira said. © 2016 BBC.