2 . If the great dinosaurs hadn’t gone extinct, would they have dominated Earth today? There has been a debate about this possibility for decades. Recently two analyses have put the surprising cognitive (认知) abilities of dinosaurs — and their potential limitations — in a new light.

In one study, Suzana Herculano-Houzel at Vanderbilt University calculated the likely number of neurons (神经细胞) in dinosaurs’ pallium, a brain structure that is responsible for advanced cognitive functions. Research suggests that it is the number of neurons in these areas, rather than the brain size, that indicates an animal’s cognitive potential. For example, despite having a very small head, birds have more densely packed brain cells than many mammals (哺乳动物) and so can possess roughly as many neurons as monkeys. The result is that some birds show great cognitive abilities, comparable to the smartest non-human mammals. And it is precisely birds, being the only surviving lineage (宗系) of dinosaurs, that are Herculano-Houzel’s foundation. By comparing the relationship between brain size, number of neurons and body size in numerous existing birds and available fossils of dinosaurs, Herculano-Houzel concludes that a large dinosaur such as T. rex could have housed two billion to three billion neurons in its pallium. If so, dinosaurs could have had the capacity for tool use and planning for the future.

But neurons’ number may not be enough. For intelligence, brain architecture also matters. And this could be the weakness of dinosaurs, argues Anton Reiner from the University of Tennessee. Over 350 million years of separate evolution, mammals and dinosaurs found two rather different ways to organize cognitive functions. The mammalian neurons are organized in a relatively thin layer formed by compact columns. In each column, different parts can communicate with one another over short distances. In contrast, in the dinosaurs that survive today, namely birds, the organization is less compact. According to Reiner, expanding brain capabilities beyond a certain point could make the structure far more complex and less efficient than it is in humans. If this were the case, an increase in brain size would correspond to a greater distance between different parts of the brain, slowing down their communication.

The issue remains open to debate. Herculano-Houzel and Reiner each published a paper with rejections to the other’s argument. Meanwhile, other scientists have entered the fight. For example, neurobiologist Giorgio Vallortigara assumes that speed in transmitting information between networks of neurons is probably one of dinosaurs’ strengths.

Whatever the truth is, understanding how and if brain architecture imposes limits on the development of cognition could reveal much about the evolution of abilities and behaviors of various animals. Also, this debate may tell us more about our own species than about dinosaurs.

3 . “Flying insects don’t fly directly to lights from far away because they’re attracted to them, but appear to change course toward a light if they happen to be passing by due to a strange inborn biological response,” writes Samuel Fabian, a bioengineer, in a research paper.

Until now, the leading scientific hypothesis has been that insects use the moon’s light to direct the way at night and mistake artificial lights for the moon. But this idea doesn’t explain why insects that only fly during the day also gather around lights.

To find out what really happens, Samuel’s team track the precise movements of insects in the wild around lights using a high-speed camera. This revealed two notable behaviours. First, when insects fly above lights, they often invert (转向) themselves and try to fly upside down, causing them to fall very fast. Just after insects pass under a light, they start doing a ring road. As their climb angle becomes too steep, they suddenly stop and start to fall. Second, when insects approach a light from the side, they may circle or “orbit” the light.

The videos show that the inversions sometimes result in insects falling on lights. It can appear to the naked eye as though they are flying at the lights. “Instead, insects turn their dorsum toward the light, generating flight perpendicular(垂直) to the source,” the team write. It is common to the two behaviours that the insects are keeping their backs to the light, known as the dorsal light response (DLR). This DLR is a shortcut for insects to work out which way is up and keep their bodies upright, as the moon or sun is usually more or less directly above them, and this direction allows them to maintain proper flight attitude and control. They also find that the insects fly at right angles to a light source, leading to orbiting and unstable flights as the light’s location relative to them changes as they move.

Samuel’s team suggest that a possible outcome of the research could help the construction industry to avoid the types of light that most attract insects.

4 . Episodic memory (情景记忆) allows humans to revisit past personal experiences in their minds, and it was once thought to be a special skill of humans. Although there are still arguments about the extent of this type of memory in non-human animals, scientists have proved that creatures like rats and dogs can pass tests that are developed to assess episodic memory over the past two decades. “Curiously, there is a lack of research investigating dolphins’ episodic memory,” University of Cambridge cognitive (认知的) scientist James Davies says. Therefore, this surprising fact encourages him to fill this gap.

The team used “where” and “who” questions in their research, each on a different test. Each dolphin was first trained to retrieve a ball from the water, and then trained to get a ball by approaching a person holding it in front of them while ignoring an empty-handed person standing at a different spot. During this training, the locations were randomized (使随机化) and the person holding the ball differed each time, so that those details were irrelevant to learning the retrieving behavior. Then, for the tests, the dolphins were asked to retrieve the ball as they had learned to do, but after 10 minutes, something changed-this time, the ball couldn’t be seen, as it was now behind one of the two people’s backs. In the “where” tests, the ball was hidden in the same spot as in the training, but both people had been changed, while in the “who” tests, the locations of the people changed but the ball remained with the person who’d had it previously.

Eight dolphins went through each of the two tests, separated by at least 48 hours. All the dolphins got it right in choosing the correct spot on the “where” experiments, and seven achieved success on the “who” experiments.

Kelly Jaakkola, a psychologist, says that based on their cognitive skills, dolphins are a good candidate for having episodic-like memory, and this study goes really far in showing that. She also says, “The more we look for such capabilities in non-human animals, the more species we’ll likely find them in.” She adds, “An exciting question is therefore ‘Where do we draw that line? Which animals do have it, which animals don’t, and what sort of cognitive or neurological or social characteristics do those animals share? ’ That’s going to be the fun part of the game.”

5 . Every day, thousands of rangers patrol national parks and other protected areas in Africa. Their job is fraught with danger, both from hostile humans armed with automatic weapons and from the unappreciative and potentially aggressive wildlife, armed with tusks, teeth and claws, which they are helping to preserve.    1    

That is particularly true of data on poaching (偷猎), which remains, in both senses of the word, an elephantine problem. Since 2006 African elephant populations have declined by around 30%. In 2021, according to Monitoring the Illegal Killing of Elephants (MIKE), a conservation programme, around 40% of elephant deaths were a result of poaching.

    2     The MIKE data show a welcome fall in rates throughout the 2010s, but according to research published in 2020 by Scott Schlossberg of Elephants Without Borders, a charity, this can be attributed entirely to a decline in eastern Africa.

Elsewhere, there is great variation in the pressure on animals like elephants. Some parks, like Garamba in the Democratic Republic of Congo (DRC), are badly hit — with more than 90% of the bodies found by rangers being victims of poachers.     3    To untangle the factors influencing poaching, Timothy Kuiper of the University of Cape Town, Eleanor Milner-Gulland at Oxford, and a team of collaborators have analysed data collected for MIKE by rangers from 64 sites in 30 African countries over the course of 19 years. They correlated these with potentially relevant factors, both natural and human, and have published their findings in the Proceedings of the Royal Society.

Natural variables such as habitat type, they discovered, make little difference.     4     Unsurprisingly, low household wealth, poor health, poor law enforcement and poor national governance all contributed to higher rates of poaching. So did the price of ivory.

    5     For there did not seem to be much. The impact was a consequence of a few special cases in DRC, the Central African Republic and Ethiopia, rather than a general rule about young men with guns behaving badly.

One factor that was unquantifiable, and therefore untestable, according to Dr Kuiper, was local political will to preserve wildlife. But this study does nevertheless confirm observations made elsewhere, that the best form of conservation is a prosperous population.

6 . Laughing together is an important way for people to connect and bond. And though the causes of laughter can vary widely across individuals and groups, the sound of a laugh is usually recognizable between people belonging to different cultures.

But what about animals? Do they “laugh”? And are the causes of animal and human laughter alike? In humans, people may laugh when they hear a joke, or when they see something that they think is funny, though it’s unknown if animals’ intelligence includes what humans would call a sense of humor.

However, many animals produce sounds during play that are unique to that pleasant social interaction. Researchers consider such vocalizations to be similar to human laughter. Recently, scientists investigated play vocalization to see how common it was among animals. The team identified 65 species that “laughed” while playing — most were mammals (哺乳动物), but a few bird species demonstrated playful laughter too. Reports of playful laughter were notably absent in studies describing fish, perhaps because there is some question as to whether or not play exists at all in that animal group. This new study could help scientists to analyze the origins of human laughter.

But how can we identify play? Unlike fighting, play is usually repetitive and happens independently of other social behaviors, said lead study author Sasha Winkler, a doctor of biological anthropology at the University of California. When it comes to identifying it, “you know it when you see it,” Winkler told Live Science. One sign is that primates — our closest relatives — have a “play face” that is similar to the expressions of humans who are playing.

When Winkler previously worked with rhesus macaques, she had noticed that the monkeys panted (喘气) quietly while playing. Many other primates are also known to vocalize during play, she said, so a hypothesis (laughter in humans is thought to have originated during play) supported by the play-related panting laughter of many primate species was put forward.

People now still laugh during play, but we also integrate laughter into language and non-play behaviors, using laughter in diverse ways to express a range of emotions that may be positive or negative. Human laughter notably differs from other animals’ laughter in another important way: its volume. People broadcast their laughter loudly, often as a way of establishing inclusion. By comparison, when most animals laugh, the sound is very quiet — just loud enough to be heard by the laugher’s partner.

“It’s really fascinating that so many animals have a similar function of vocalization during play,” Winkler told Live Science. “But we do have these unique parts of human laughter that are also an important area for future study."

7 . Clown fish live their adult lives in the protective arms of sea anemones, the small brightly colored sea animals attached onto rocks to house clown fish. Between birth and adulthood, however, the fish have to complete a treacherous journey. After hatching, they swim out to the open sea to finish developing. After maturing, the young fish swim back, during which they have to avoid a “wall of mouths” by sensing the unfriendly smells. With ocean acidification, a trend that is occurring worldwide, scientists began to wonder what might happen to fish’s sense of smell.

My team put 300 recently hatched clown fish in our lab. When we introduced a friendly fish odor (气味), they did not react. But when we introduced an enemy odor, they swam away. We then repeated the experiment with 300 new hatchlings from the same parents in the more acidic water-a level we can expect by the year 2100 if current trends continue. When we introduced friendly and unfriendly smells at the same time, the fish seemed unable to make up their minds, spending equal time swimming toward one smell and the other. They could sense chemical signals but couldn’t recognize the meaning of them.

It is always tricky to say that behaviors seen in a lab would also be seen in the wild. So we went to a sandy lake near one of the Great Barrier Reef’s northern islands to test how wild-caught damselfish would react to enemy smells after exposing them to acidic water. In a tank, about half of them held in water with acidity expected by 2050 were attracted to the unfriendly odor and half were not, yet not one held in water anticipated by 2100 avoided being attracted to the enemy odor. We then let the marked damselfish loose in the lake. The fish once held in the most acidic water swam farther away from their protective home. Can fish adapt? Most studies have habituated fish to lifted acidic conditions over a few days or months-an extremely short length of time. The animals are not given a realistic opportunity to adapt. Yet some scientists thought that fish might escape the anger of ocean acidification, in part because early research done in the 1980s showed that certain animals had an astonishing ability to regulate their internal chemistry to survive acidified water. But maintaining normal functions such as avoiding danger is a different challenge.

At a minimum, confusion could place yet another stressor on fish already challenged by rising water temperatures, overfishing, etc. Further, if many ocean creatures start to behave strangely, entire food webs and ecosystems could come crashing down. Although the science is still new, the results appear to be lining up: ocean acidification is messing with fish’s minds.

8 . Many people would answer the question of what makes us human by insisting that we are cultural beings. There is no doubt that we are. But one definition of culture is the totality of traditions acquired in a community by social learning from other individuals, and many animal species have traditions. Can we then say that some animals are cultural beings too?

One approach to study culture in animals is the so-called Method of Exclusion (排除), in which scientists investigate behavioral variations across populations of one species. In a famous study, scientists learned that chimpanzee (黑猩猩) behaviors were socially passed on as they were present at some sites but not at others, despite having same ecological settings. For example, chimpanzees in Tai National Park in Ivory Coast are well-known for their nut-cracking skills. Chimpanzees in Gombe national part in Tanzania, on the other hand, do not crack nuts, although nuts exist in their environment too.

However, when applying the Method of Exclusion, one has to be very careful. There are other factors that could also explain the pattern of behavioral evaluation. For example, some of the chimpanzee techniques scientists evaluated occur in only one of the three subspecies. So it’s quite possible that these behaviors also have an innate component. This would mean that one chimpanzee subspecies uses a new technique not out of cultural tradition, but because the behavior is fixed to specific genes. Another factor that has to be excluded is of course the environment Chimpanzees in Mahale do not fish algae (水藻), simply because algae does not exist there.

But when we exclude all the variations that can be explained by genes or environment, we still find that animals do show cultural variations. Does that mean there is no real difference between them and us after all? Not exactly: There is a fundamental difference between human and animal culture. Only humans can build culturally on what generations before us have learned. This is called “cumulative culture”. We don’t have to keep reinventing the wheel. This is called the “ratchet (棘轮) effect”. Like a ratchet that can be turned forward but not back, people’s cultural techniques evolve.

It is likely that behaviors we see today in chimpanzee cultures could be invented over and over again by individual animals themselves. In contrast, a child born today would not be able to invent a computer without the knowledge of many past generations.

10 . A few years ago, the City Council of Monza, Italy, barred pet owners from keeping goldfish in curved fishbowls. The sponsors of the measure explained that it is cruel to keep a fish in such a bowl because the curved sides give the fish a distorted view of reality. Aside from the measure’s significance to the poor goldfish, the story raises an interesting philosophical question: How do we know that the reality we perceive is true?

Physicists are finding themselves in a similar trouble to the goldfish’s. For decades they have been pursuing an ultimate theory of everything—one complete and consistent set of fundamental laws of nature that explain every aspect of reality. It now appears that this pursuit may generate not a single theory but a family of interconnected theories, each describing its own version of reality, as if it viewed the universe through its own fishbowl. This concept may be difficult for many people to accept. Most people believe that there is an objective reality out there and that our senses and our science directly convey (传达) information about the material world. In philosophy, that belief is called realism.

In physics, realism is becoming difficult to defend. Instead, the idea of alternative realities is a mainstay of today’s popular culture. For example, in the science-fiction film The Matrix the human race is unknowingly living in a simulated (模拟的) virtual reality created by intelligent computers. How do we know we are not just computer-generated characters living in a Matrix-like world? If—like us—the beings in the simulated world could not observe their universe from the outside, they would have no reason to doubt their own pictures of reality.

Similarly, the goldfish’s view is not the same as ours from outside their curved bowl. For instance, because light bends as it travels from air to water, a freely moving object that we would observe to move in a straight line would be observed by the goldfish to move along a curved path. The goldfish could form scientific laws from their frame (框架) of reference that would always hold true and that would enable them to make predictions about the future motion of objects outside the bowl. If the goldfish formed such a theory, we would have to admit the goldfish’s view as a reasonable picture of reality.

The goldfish example shows that the same physical situation can be modeled in different ways, each employing different fundamental elements and concepts. It might be that to describe the universe we have to employ different theories in different situations. It is not the physicist’s traditional expectation for a theory of nature, nor does it correspond to our everyday idea of reality. But it might be the way of the universe.