Humans

Alex Re (00:00): Hello, welcome to On Wildlife. I'm your host Alex Re. On this podcast, we bring the wild to you. We take you on a journey into the life of a different animal every week, and I guarantee you you're going to come out of here knowing more about your favorite animal than you did before. It's our 100th episode. It's pretty crazy that we started on wildlife almost two years ago today. So to celebrate this milestone, we're going to do a special episode on an animal that you know pretty well. This animal has had the single greatest impact on the world as we know it today. And because of that, it's going to be a little bit of a longer episode. So get ready to look at your own family tree because today we're talking about humans.

(01:01): Human is a term used to refer to the group of primates in the genus Homo. Throughout history, there have been nine species that make up this genus. The species are homo habilis, rudolph fences, erectus, heidelbergensis, neanderthalensis, ti, sapiens, fluoresces and ensis. But unfortunately, every species of human has gone extinct except for one homosapiens, which is us. Humans are related to the great apes and have similar anatomical structures, but have a more highly developed brain, which allows us to do more abstract thinking and have complex speech. For a long time we thought the difference between humans and apes was greater, but now we're realizing that apes are a lot more intelligent than we assumed. Somewhere between 800,000 and 200,000 years ago, the human brain became more complex and this coincides with our increased innovation of tools as well as behaviors like cooperation and gathering around shelters.

(02:05): Humans also stand fully erect, and this has freed up our hands to be used from manipulating tools rather than having to use them for locomotion like other apes. But even so, all humans and apes possess opposable thumbs that help them grasp onto objects in their environment. The first species of human homo habilis began walking the earth around 2.4 million years ago, and they lived in Africa. We found their fossils in Tanzania in the 1960s. Homo habilis means handyman and they were named after their proclivity for making and using stone tool. Homo Habilis was a smaller species of human that weighed about 70 pounds, and they stood between three and a half and four and a half feet tall. They went extinct about 1.4 million years ago and they were the sole member of the homogeneous. For about a million years, homo Rudolph fences was the next species of human to live on earth, showing up just before Homoerectus around 1.9 million years ago.

(03:08): So let's talk a little bit more about Homoerectus, which is one of the most well-known human species. They were the first species of human to stand fully upright, and they took their first steps on the continent of Africa about 1.89 million years ago. Their legs were adapted more so for running and walking rather than climbing trees like their ancestors. They were also the first species of human that had a much larger brain case than the apes that came before. It remains of campfires have been found near Homoerectus fossils, and this led us to believe that they were the first species of human to begin cooking their food over fire to make it easier to digest. And this process of cooking meat helped their brains develop much more quickly because they were now able to focus more energy on their brains and less energy on digesting food.

(03:59): Homoerectus had the longest reign of any human species lasting almost nine times longer than we have today. Hundreds of thousands of years later, a new species emerged. Homo Neanderthalensis, also known as Neanderthals. Neanderthals were a completely different species than us, but they were our closest relatives. There was even mating occurring between us and Neanderthals. A modern human has anywhere from one to 8% of Neanderthal d n a in their genome. Neanderthals were shorter in stature and had stockier builds than we do, but their brains were about as large or maybe even larger than that of homo sapiens. These guys were found in Europe and some parts of Asia to survive. In colder climates, Neanderthals made fire, but they were also able to make clothing and their remains have even been found with sewing needles made of bone. They also made much more advanced shelters than previous humans.

(04:59): Scientists believe that Neanderthals also buried their dead in marked graves, suggesting these symbolic behaviors were a sort of language which would later influence our own language. In breeding, climate change and clashing between our species and theirs is believed to have led the Neanderthal down the path to extinction. Most Neanderthals died out around 40,000 years ago, but the last groups survived in Gibraltar until 28,000 years ago. Homo sapiens first appeared on earth around 300,000 years ago. That's us. We started off in Africa, but after making it to Europe, we began to steadily outmatch our other living relatives anywhere we went. The numbers of other human species would dwindle by competing with other species of humans for food and territory. We became the dominant species, but it could have easily been another species in our place if we weren't as successful. There were some human species that appeared after we did like a species nicknamed the Hobbit Homo fluoresce.

(06:03): They lived between a hundred thousand and 50,000 years ago on the island of Flores in Indonesia. These humans were very short, only growing to three and a half to four feet long at their largest. They the biological concept of insular dwarfism where animals will be smaller when their range is restricted due to living on small islands. While there have been nine official species of humans, there may be more that science just hasn't discovered yet, and since homo sapiens has appeared, we have walked the earth with six other human species. For the rest of the podcast, when I'm talking about humans, assume that it's about our species homo sapiens because it's the only one left. Okay, now that we've had a brief history lesson on humans, we're going to take our first break, but when we get back we'll talk about the human diet. This week I want to give a shout out to Jack from Maryland. His favorite animal is an otter. Did you know that otters have the thickest fur in the animal kingdom? This helps keep them warm in the water. If you want me to give you a shout out on the podcast, send an email to on wildlife dot podcast@gmail.com telling me your first name, where you're from and your favorite animal.

(07:35): Now back to the episode. The diet of humans has shifted many times throughout our history, and it often came down to what was available at the time, but when there's no scarcity in food is when humans have gotten creative with what they eat. The earliest human diets are similar to those of great apes like chimpanzees. They were omnivorous and often ate lots of fruit, bark, meat leaves and insects. Their teeth may have allowed them to eat hard seeds, nuts and roots too. At some point early on in our timeline, humans began to eat more and more meat, even incorporating bone marrow into their diets, and this is after we started using tools to butcher animals. The addition of meat to the diet has been linked to a decrease in the size of our teeth and gut, but an increase in the size of our brains and bodies.

(08:28): Carnivore in humans is unique among primates because of three major factors. First, humans use tools made of f flaked stone to cut meat off the animal and take it with them for later consumption. Humans also gathered food from animals much larger than themselves, resulting in more available resources, and humans were able to scavenge for most of this food rather than strictly having to hunt it. These methods of food collection contributed to the hunter gatherer lifestyle that humans have employed for hundreds of thousands of years. Hunter gatherers are classified as nomadic, people who live on diets consisting mainly on food from hunting, fishing, and other harvested wild resources like berries. Hunter gatherers were travel long distances in search for food and some of the areas that humans used to hunt and gather ranged in size from a few square miles up to almost 500 square miles.

(09:24): The hunter gatherer lifestyle prevailed for many years, but around 12 to 13,000 years ago, humanity underwent an agricultural revolution known as the neolithic revolution. As farming started to develop some groups of hunter gatherers reconsidered their old practices and began to build permanent settlements where larger populations could be housed. These permanent settlements would later give way to the towns and cities we have today. One of the most important crops that we domesticated was wheat. We started growing it around 10,000 years ago, even though this gave way to everything we have today. Some people believe that humans actually had a much better quality of life when we were just hunter gatherers. They claim that instead of humans domesticating wheat, wheat actually domesticated us because it caused us to have to settle down to one place and spend countless hours making sure that the wheat stays alive. When we were hunter gatherers, we were able to relax for most of the day and only hunt or forged for food for a few hours.

(10:29): In these modern times we live in, agriculture is still a great means of food production. Just one farm can produce enough food to feed over 150 people. We also have massive factories churning out processed foods that are packaged and shipped across the world. And of course, instead of having to hunt down animals, we have domesticated them. The first domesticated animals were thought to be goats and dogs were domesticated somewhere between 14,020 9,000 years ago. Domestic animals are bred to have certain traits and calmer behaviors than their wild ancestors. For example, dogs were domesticated from gray wolves that began to hang around early humans, but now there're a completely different species. Unfortunately, the domestication of livestock like cows, chickens, pigs and goats has turned into a cruel process for the animals. They oftentimes have to live their lives in cages without the mental stimulation that they need.

(11:30): This problem has really come about because we have so many people to feed and corporations are willing to cut corners to make the process as cheap as possible. The average American eats over 240 pounds of meat every year, and there's over 300 million people that live in the US alone. That's a lot of meat, and this isn't only a problem for the animals, but it's also hurting our environment. Slaughterhouses create a huge amount of waste that gets washed into our rivers and lakes that can just devastate the ecosystem, so although it's convenient for us, it's causing a lot of harm in a bunch of different ways because there are so many choices available when it comes to food. There are many different diets that have sprung up. Historically speaking, humans have been omnivores, but now there are also those who have cut meat out of their diets.

(12:21): Vegetarians only eat meat from fish in addition to all other non-meat products, pescatarians and even people who don't consume any animal products. Vegans, because we've evolved to be able to eat so many different foods, you can live a completely healthy lifestyle living on any of these diets. Diets are also tied to cultures and geographic locations. Food also plays a large part in the human mating ritual as two individuals will often share a meal together in order to figure out if they're compatible mates. This is called a date. Humans have a gestation period of nine months, and for the most part, they give birth to one baby at a time. In some cases, you can have twins, triplets, or even more. Because humans are mammals, females are able to provide milk to their offspring that have all of the nutrients they need for survival, and in many cases, mothers don't need to produce their own milk because baby formula can be a good substitute.

(13:21): After babies are weaned off, they start to eat solid food and will continue to do so for the rest of their life. Adolescent humans need support from a parental figure in order to develop properly. Many babies in the animal kingdom have their behaviors hardwired into them from birth, but humans develop most of their behaviors, especially their language by learning from adults. But did humans mature more quickly thousands of years ago when times were a little bit more difficult? Researchers were able to figure this out by looking at our teeth. Scientists used CT scans to count the layers of enamel on human teeth and determine our rate of growth. The data showed that prehistoric human children aged at the same rate as modern humans, but our life expectancy has dramatically increased as time has gone on. Studies have found that during prehistoric times, Neanderthals and humans had pretty similar life expectancies where 75% of adults would die before their forties, and if you were born at the turn of the 20th century, it was likely you wouldn't make it to see 50.

(14:28): But now with medical advances and better living conditions, lifespans are on the rise. The trends are similar in both men and women. With the lifespan increasing by about three months for each year between 1840 and 2009, the average life expectancy for a person in the US is 81 years for women and 77 years for men. Both Hong Kong and Japan have the highest overall life expectancies with the average person living to be about 85 years old. The oldest recorded human being lived to 122 years and 164 days old. Her name was Jean Louise Kalman and she claimed that chocolate and wine helped her live so long. Scientists agree that there must be a biological limit to how old we can get because there aren't many people who make it past 110. With our living conditions being much different from our prehistoric ancestors, it's no wonder many of them didn't live past their twenties and thirties. They had to face a harsh climate and huge predators hunting them down, but our ancestors persisted. Let's talk about some of the reasons that we were able to survive right after the break. Here's today's trivia question. True or false, you're taller in the morning than you are at night.

(16:05): The answer is true. The soft cartilage that cushions your bones gets compressed over the course of the day and you're actually one centimeter taller right when you wake up than when you are going to bed.

(16:26): Okay, welcome back. Humans have always been highly social animals with many of our social behaviors helping us overcome the day-to-day challenges in our different environments. Cooperation was extremely important because we needed to work together to take down prey that was so much bigger than us like woolly mammoths. Eventually this led to us starting to develop a spoken language. One of the most important parts of language that you really don't think about is gossip. We're all told gossiping is bad, but there's a reason that gossip is so entertaining to us. It's actually an evolutionary advantage because we lived in tight-knit communities. It was important to know everyone in the group and to know who you could and couldn't trust. Gossip was our way of figuring out if there was someone in the group that was untrustworthy or that was not doing their fair share so that we could stay away from that individual.

(17:23): Humans started sharing resources around 1.8 to 2.6 million years ago. Early humans began to collect things then bring them back to their favorite spots. Some of them took stone and transported it miles away to use for toolmaking by meeting their other group mates at these spots, they would share the resources and form bonds, and in turn, this gave all of them a better chance At survival. Starting around 800,000 years ago, humans began to meet around campfires that they built, and by 130,000 years ago, humans interacted with other social groups spread out all over the world. They started off meeting other groups from tens or hundreds of miles away, but as time went on, social networks expanded and grew more in complexity. By 40,000 years ago, the trade distances had almost doubled increasing their ability to survive. Scientists originally thought that social growth was gradual where our pairs grew to clans and then became larger communities.

(18:26): Newer studies have shown that social growth in primates expanded rapidly in bursts because they were much safer when there were more individuals in the group. Another beneficial effect of living in a community is cooperative caregiving for young. If parents were unable to look after their children for any reason, others were able to step in and help them out resulting in a lower child mortality rate. As time went on and keeping our species from going extinct, even though humans have been around for 300,000 years, it wasn't until 100,000 years ago that we started to exhibit behavioral modernity. Behavioral modernity is basically when we started acting like modern day humans. Modern behavior is recognized by language technologies of a complex nature, art, creative culture, religious beliefs, and more. Humans have many behaviors that have evolved over the years, and we'll go over a couple. For instance, we talked a little bit earlier about language.

(19:28): There are over 7,000 languages in the world, but that doesn't mean all of them are widely spoken. More than half the world only speaks 23 languages In total. Before written languages were developed, early civilizations likely used symbols to represent ideas. Another behavior that sets humans apart from almost all other species is their ability to wage war on one another. Wars have been fought over territory, resources, grudges, or various other reasons. Some other species may engage in behaviors that are similar to war, like colony based insects, which wage war over resources or chimpanzees who send war parties out to kill members of other groups in order to whittle down their opposition. Humans are also the only species that has evolved cooperative caregiving. For individuals who have contracted diseases, we have a unique ability to look at another person and find out information about their health. This is beneficial because it allows more individuals in the community to survive.

(20:31): There's always a part in the podcast where I start talking about how an animal impacts its ecosystem. Well, humans have been impacting ecosystems for hundreds of thousands of years, usually not in a good way. We can impact the environment through various means, including pollution, deforestation, overpopulation, and overhunting. These impacts have triggered countless cascading changes that make the environments we touch almost unrecognizable. There's air pollution that comes in many forms, the main way being carbon dioxide emissions through burning fossil fuels. This is causing a greenhouse effect on the earth where heat is trapped and the earth starts to warm up. This may not sound like a big deal, but it causes a countless number of issues like a rise in sea level, an increase in the amount of insects and diseases, more natural disasters and the death of coral reefs. Then there's noise pollution caused by nonstop sounds from cars, trains, and boats.

(21:31): This kind of pollution impacts animals that rely on sound to communicate with each other like frogs, birds, whales, and dolphins. Deforestation happens when we cut down and destroy ecosystems so that people can either harvest resources or build new developments for people to live in. Our population is almost at 8 billion people and it's only getting larger In 2050, we predict that there will be 10 billion people in the world. We need a place for all of these people to live, so we have to keep cutting down forested areas. This removes all of the species that need those areas to survive, and it also increases our encounters with dangerous animals like bears and even tigers in certain areas of the world. Also, because of the increasing population, we need to keep producing more and more food, so that causes us to over hunt and overfish. This isn't a new problem.

(22:26): We've been driving animals to extinction for hundreds of thousands of years. Researchers have found that anywhere humans have traveled, we've caused the largest animals in that area to go extinct. We've definitely gotten better over the years, especially before and up until the 19th century, we were just killing endangered species for fun. One of the most commonly known extinct animals is the dodo bird. These were large flightless birds. Well, in 1507, humans first discovered them and it took us less than 200 years to drive them completely to extinction. So needless to say, we've done a lot of harm to the environment and we're still doing it, but there are ways that we can actually improve the ecosystems around us. There are so many people that are helping all living species thrive, working to change our world for the better, and there are ways to maintain a similar lifestyle that we currently have, but be more thoughtful about how we do it.

(23:25): If we keep going at this rate, we're going to be forced to change how we live, so it's better to do it on our own terms. It's time for us as humans to make more of an effort to take care of the natural world or else there won't be any natural world for us to enjoy. One way to do this is through the process of rewilding where work to promote biodiversity by reintroducing plants and animals to previously inhabited ranges. We can also think about ways to get our energy besides just using fossil fuels like solar, wind, hydroelectric, and even nuclear energy from Homo Habiliss first steps on Earth to the first steps on the moon, and all advancements made. Since then, humans have made some truly amazing jumps in our history and we have our ancestors to thank for that. If not for the strategies that they employed to live in this harsh world, we wouldn't be here today and it could very easily have been another species dominating the world.

(24:24): With all that in mind, it's easy to forget that we're animals too, but we can make conscious choices to help make the world a better place. If you want to help with wildlife conservation, check out the Wildlife Conservation Society, the World Wildlife Fund, and the Nature Conservancy. Thank you so much for coming on this adventure with me as we explored the world of humans. You can find the sources that we use for this podcast and links to organizations that we reference at onwildlife.org. You can also email us with any questions at On Wildlife dot podcast@gmail.com, and you could follow us on Instagram at On Wildlife or on TikTok at wildlife. Don't forget to tune in next Wednesday for another awesome episode, and that's On Wildlife.

Jess Avellino (25:20): You've Been listening to On Wildlife with Alex Re. On Wildlife provides general educational information on various topics as a public service, which should not be construed as professional financial, real estate, tax, or legal advice. These are our personal opinions only. Please refer to our full disclaimer policy on our website for full details.