Primates make laughter when they play. However, laughter in animals often means an invitation to mate, join a herd, or find food. The meaning of animal laughter Laughing together helps people connect and bond. Although the reason for laughing can vary widely between individuals and groups, this sound can still be distinguished from crying, screaming, groaning or shouting. In humans, laughter expresses a wide range of emotions, from positive such as amusement to negative such as annoyance. People laugh when they hear an interesting story or when they see funny things. But what about animals? Do they laugh and is the reason they laugh the same way humans laugh? It’s hard to tell if animals have a sense of humor like humans. A study published in the journal Bioacoustics in April 2021 found that when communicating, animals sometimes make sounds that have a comforting, pleasant nuance. Sasha Winkler, lead author of the study, at the University of California, Los Angeles (USA), said that rhesus monkeys (scientific name Macaca mulatta) often pant when playing. This is the inspiration for her and her colleagues to expand their research on animal laughter. They looked to see if other animals let out gasps like rhesus monkeys during play. The researchers say that such sounds closely resemble human laughter. They continued to study the prevalence of laughter among animals. The team identified 65 species that “laughed” while playing, most of which were mammals. Some birds also make cheerful sounds. This analysis helps scientists go back to the evolutionary origins of laughter in humans. When playing, animals may cry or laugh to keep interactions at a harmonious level, not becoming aggressive. Unlike fighting, the concept of play in animals is often mating, foraging. Play can be clearly seen in primates because their facial muscles show human-like expressions when playing. The study grew out of an experiment from 2017 on kea parrots living in New Zealand. Experts recorded the laughter of the kea parrots and played them back for others to hear. As a result, these parrots will play together relatively closely. This study shows that the laughter of kea parrots is like an invitation to others to join the flock or to feed together. Investigation results show that mammals, especially primates, rodents, carnivores and cetaceans emit similar sounds. These sounds are only emitted when playing, such as the whistle like the whistle of a bottlenose dolphin (scientific name is Tursiops truncatus), the hiss of a mouse. Most primates, including chimpanzees, gorillas, monkeys, and baboons, exhibit laughter by: panting, smirking, chuckling to “click, clack” and loud cries. . Birds emit laughter to attract their fellow humans. Laughing is not just for fun Research also shows that fish, amphibians and reptiles do not produce laughter because this group may not organize play activities. However, laughter between humans and animals is quite different. Usually, people’s laughter shows that they are having fun or sharing their joy with those around them. People also put laughter into communication to express their attitudes and feelings towards the behavior of people around them. For example, smirking, sarcastic laughter, sarcastic laughter to express a reaction of praise or disapproval of the actions of people around. But in some animals, laughing is not synonymous with cheerfulness. For example, hyenas often laugh when feeling dangerous, threatened, attacked or simply upset. Human and animal laughter also differ in volume. For example, older hyenas often laugh at a low pitch while young hyenas’ laughter is high, even shrill. Some species laugh very softly, just enough for the other person to hear. While human laughter is loud, loud and nuanced. Before Winkler, in 2000, Jaak Panskeep, a psychologist and neuroscientist working at Washington State University, USA, discovered that tickled rats emit chirping sounds similar to the sounds they make when they play. Some lab rats liked to be tickled so much that they simulated this amusing activity. From there, Panskeep and his colleagues began to seriously study the play of animals. He identified seven basic emotional expressions activated by the mammalian brain. Since then, he has applied this result to the study of human emotions and found a treatment for depression in humans. Panskeep has clinically developed an antidepressant, named GLYX-13. He considers this modulation product to be proof that scientists should seriously evaluate the emotional state of animals. Animal studies could pave the way for the development of psychopharmaceuticals for humans. He also added that we think rats and monkeys can laugh because they are smart. But in fact, intelligence is not a funny factor. Play in any animal can stimulate laughter, increase cognitive ability.

Everyone longs for a “paradise” free from disease, war, and oppression, although this paradise may not exist, but with the development of science, technology and society, we are getting closer. to heaven in the eyes of the ancients. We will also be curious about the future of human society. There are countless works trying to construct an impossibly beautiful perspective for exploring such issues, most of which of course have pessimistic results. In 1798, the British demographer and economist – Malthus showed in his thesis “Principle of Population” that the population increased exponentially but food production increased linearly. If things continued like this, it would reach a point where the population could no longer grow. The hidden content of this theory is that population growth does not necessarily bring prosperity, but can cause socioeconomic stagnation, hence the so-called “Malthusian trap”. After the end of World War II, the world gradually returned to prosperity, the United States ushered in a period of population explosion with a series of babies after the war, and with it, pessimistic views began to emerge. . Some people think that “overpopulation” can lead to a crisis, which in the short term will deplete resources for survival. This mentality of the majority of the population was immediately drawn to Malthus’ ideals. However, the success of the Green Revolution made Malthus’s model no longer valid, as food production spiked. However, the fear surrounding population explosion and its consequences still lingers here and there. Accordingly, a series of experiments demonstrating the effects of population explosion emerged. But a series of animal experiments seem to have yielded surprising results. Human estimates of resources for survival may still be too optimistic, but the real crisis coming from the population itself will seem obvious. The most prominent of which is the experiment of John B. Calhoun, an American expert specializing in the study of ethology and human behavior. John B. Calhoun and the Norwegian Rats. Calhoun was particularly interested in studying birds during his early years, and one of his studies was published in the journals of the Tennessee Bird Society at the age of 15. After that, Calhoun studied from bachelor’s degree to doctorate, and his research direction also gradually turned to animal behavior. Since his doctoral thesis was to study the 24-hour rhythm of the Norwegian rat, Calhoun’s work after graduation was also closely related to this rat. In 1947, Calhoun, then working at Johns Hopkins University, asked a neighbor to buy a piece of land less than 1,000 square meters to use as a laboratory. Then he decided to build an “artificial rat paradise” so that his rodents could live carefree. In the end, Calhoun named the place “Rat City”. With this amount of land, the area of ​​​​the mouse city is not small, it is estimated that it can accommodate 5,000 rats, Calhoun also provides adequate food and water for his mouse subjects, while minimizing the maximum. the impact of disease and predators. Rats are only allowed to operate within the “city”. However, the development of the mouse city was not as smooth as imagined, even a bit bizarre. Calhoun initially included five pregnant female mice, but the reproductive rates of mice in this range were not as high as he had imagined. The number of rats in the study area never exceeded 200, and it stabilized at about 150, much smaller than the number of rats this “artificial paradise” could accommodate. Live rats cluster together in groups, and feed only at specific spots. This may have been the first experiment that brought Calhoun’s attention to population density. Five years after the failure of the rat city project, Calhoun joined the US National Department of Mental Health (NIMH) and was in a better position to design experiments on mice. At that time, Calhoun had a small team working with him, they improved the experimental environment on the mice as well as specially designed the breeding area so that the “artificial paradise” could work better. . The farming area is now only about 4.5 m long, 3 m wide, divided into 4 areas separated by electric fences, each area is equipped with unlimited food and water sources, there is also a multi-storey “apartment” that rats can enter in a spiral. The 4 areas separated by the grid are actually not completely isolated from each other, they are connected in pairs by 3 small bridges. Specifically, these four regions can be considered as four quadrants in the Cartesian coordinate system, where only a direct bridge exists that causes the path to move between the beginning – area 1 and the end – area 4 creating into a U shape. Calhoun designed a special feeding system, where solid food is kept behind nets and the collection process is not easy. In the first litter, but the residents here are reasonably arranged with a total of 32 mice, the number of males and females is equal and they are all adult rats that have reached reproductive age. According to the plan, the mice in the habitat would breed quickly, and the number would exceed the 40 limit for a short time, but Calhoun wouldn’t stop the experiment immediately. He would let the rats spawn to 80 and watch them. At first, the female rats were evenly distributed in the four regions, but when the fights between the males ended, the stronger males took over more females. Due to the design of four areas and three connecting bridges, a large number of low-status male rats will be concentrated in areas two and three, while the first and fourth areas become “swarms” of mice Males have higher status. At the bridge, the rats built their own barriers that prevented individuals from walking freely. Weak mice went to cages 2 and 3 to feed and could not return, only a small number of male rats remained in cages 1 and 4. At this point, the strange thing happened, the low-status male rat living in areas 1 and 4 – despite living among the females – had no desire to mate with the opposite sex. Instead they approached higher-status male rats, but the high-status males didn’t deny it either. The number of mice in the barn for 2-3 days is dense due to the continuous appearance of new litters of mice that “go and do not return”. At the same time, the rats’ eating behavior changed as they became accustomed to Calhoun’s feeding device. They refuse to eat alone, and only engage in net scavenging activities when and only in the presence of their own. The pressure from the population, from feeding (despite the abundance of food) creates a pattern that Calhoun calls a “behavioural sink”, roughly translated as “behavior alienation”; Rats begin to develop harmful behaviors. Under the influence of behavioral alienation, female rats have increased social interaction and decreased ability to care for offspring – and because young rats rely heavily on their mothers, herd numbers are at risk of decline. Whenever female mice move their nests, they often leave behind a large number of young mice. And yet, at the time of estrus, because female rats live in closed cages, they cannot escape from the males, and the brutal mating behavior in the cage affects the young even more. At one point, the mortality rate in the rat cage reached 96%. In dominant males, behavioral corruption causes them to become hysterical, frequently attacking their cagemates and even their young. In the vulnerable group of mice, Calhoun found traits that could separate mice into three distinct groups: The first type is called “pansexual”, they do not participate in competitions for social status, but will try to mate with any rat possible regardless of gender. or age. Not many individuals refuse this behavior. The latter, which Calhoun calls a “somnambulist”, is slow-moving, barely interacts with other rats, does not participate in social activities, and very few other individuals interact with them. ., but they are extremely fond of taking care of their appearance and are never violent. The third category, the group that most surprised Calhoun was named the “probes”. These are hyperactive individuals, constantly looking for opportunities to mate with rats of both sexes. Even if they were attacked by higher-status male rats, they would still frantically pursue females in heat. Once they reached the slums and found the young left behind, the fugitives found another source of nourishment. Continue: The end of the gruesome experiment, and the premise of the next one.

Genetically modified mosquito larvae will be released in the US. Oxitec has previously released the aegypti Aedes mosquito in Brazil, the Cayman Islands, Panama and Malaysia, and the company has reported that the local strain of A. aegypti has reduced by at least 90%. A. aegypti can carry diseases such as Zika, dengue, chikungunya and yellow fever, and the release of genetically modified mosquitoes is one way to control this population without the use of insecticides. Oxitec’s genetically engineered mosquitoes are male, engineered to carry lethal genes; When genetically modified pests mate with wild female mosquitoes, the lethal gene is passed on to their offspring. Although the gene does not affect the survival of males, it prevents females from building an essential protein and thus causes them to die before adulthood. Only female mosquitoes bite humans (male mosquitoes only drink nectar), so denatured mosquitoes and their surviving males cannot transmit disease to humans. A. aegypti mosquitoes make up about 4% of all mosquitoes in the Florida Keys but cause the majority of mosquito-borne diseases in the area. The region typically spends $1 million a year on mosquito control, resorting to costly measures such as aerial spraying. Release of hundreds of millions of genetically modified mosquitoes could be a less expensive and more effective option, especially as mosquito populations become resistant to pesticides over time. Oxitec was approached by the local government in 2010, and after a decade of regulatory review and local feedback, both the board and the U.S. Environmental Protection Agency finally approved the plan. Release of genetically modified mosquitoes in the Keys. At the end of April, the company placed boxes of mosquito eggs at six locations in Cudjoe Key, Ramrod Key and Vaca Key, according to Nature. Over the next 12 weeks, about 12,000 newly hatched male mosquitoes will emerge from the box. This will be an initial test so Oxitec can collect data before conducting a second test with nearly 20 million mosquitoes later this year. The company will capture mosquitoes during the test to see how far the insects travel from their boxes, how long they live, and whether female mosquitoes actually pick up the lethal gene and die. To make it easier to track genetically engineered mosquitoes, Oxitec introduced a gene that causes the mosquitoes to glow under a specific color of light. The experiment was met with strong opposition from a small portion of Florida Keys residents, as well as the Florida Keys Environmental Alliance and Food Safety Center. Concerned that the boxes of mosquito eggs could be vandalized, Oxitec placed them in a secret place and did not reveal their exact location to the public. Questions remain as to whether genetically modified mosquitoes cause undesirable effects on mosquitoes, local animals, or the ecosystem at large. For example, after Oxitec released genetically modified mosquitoes in Jacobina, Brazil, genes from the insect were mutilated in local mosquito populations, suggesting that the lethal gene failed to kill some females before they can mate. According to a 2019 study published in the journal Scientific Reports, their hybrids did not carry the lethal gene, but instead carried genes from the original Cuban and Mexican mosquito populations used to create the modified mosquitoes. genes. It is unclear whether these new genes may have changed the biology of the mosquito. Molecular biologist Natalie Kofler, founder of E Edit Nature, an organization that advocates for the responsible use of gene editing, told Nature she hopes the Oxitec test will be conducted in a transparent and in a way that might make some community members feel better about the whole situation.