Skip to main content
Loading Explore guides…
Primate Behavior · Acedra
Home
Explore
Biology
Primate Behavior
Sign in to save
Chat
If YouTube asks you to sign in, open the video on YouTube.
Watch on YouTube
Reload player
Transcript
55 segments
Copy
Hide video
0:00
- I'm Tara Stoinski, chief scientist for the Dian Fossey Gorilla Fund. Let's answer some of your questions from the internet. This is Ape Support. [upbeat music]
0:12
@lyssyeager asks, "Why do gorillas pound on their chest? Does anybody know?" It is part of their display. It is part of how they show off how big and strong they are. A chest beat is with an open palm, usually cupped, and then they beat on their chest like this. The males actually have these big air sacks underneath their chest. They're bringing air into these air sacks, so it sounds like [whooshing]
0:37
This is a lower frequency chest beep from one of the gorillas that we study in Rwanda. [gorilla pounding] You're hearing the buildup as the males filling his air sacks so when they beat on them, that sound can actually carry up to a kilometer away. So the lower the frequency that these males can get actually corresponds with the males being larger in size, the rival male can get some information while he's still pretty far away about the size of the male
1:02
that he's approaching, and a female can use that information to decide, is this gonna be a good mate for me to join in the long term and to have my offspring with. @AfroNutNut asks "Google, how do bonobos settle social conflict?" Bonobos have this incredibly unique way of settling social conflict and that is basically through sex. It's male-male sex, it's male-female sex. It's female-female sex. One example is if there's a highly prized food item, so say a ripe fruit that an individual wants
1:29
and a lot of primates, they will fight over access and the dominant individual just gets priority of access over that food. In Bonobos, however, they settle that social tension by coming together, having sex, and then oftentimes sharing the food item. @BagelMannnn asks, "What's a primate?" Primates are in order within the mammals. They appeared on earth roughly 60 million years ago. These are animals that have high levels of social complexity for the most part.
1:54
They have a relatively large brain size. They have forward facing eyes, and currently there are three main categories. You have your prosimians, these are your bush babies, your tarsiers, your lorisoids, your lemurs. They are kind of considered the most primitive of the primates. Then you have your monkeys. New world monkeys are found in central and South America. They include capuchin, spider monkeys, howler monkeys, squirrel monkeys. And then you have your old world monkeys
2:21
that are found in Asia and Africa. And there you think of baboons, you think of langurs, you think of blue monkeys, sykes' monkeys, and then you've got the apes. This includes the smaller apes, the gibbons and the simian, and then the great apes, orangutans, bonobos, gorillas, chimpanzees and humans. @ITSFACEBABY asks, "How do some apes communicate with other apes? Is there a secret discord or something?" They communicate a lot through vocalizations. One of my favorites is
2:48
what we call the pig grunt in gorillas. It sounds a little like [grunting] And it's kind of a mild warning like leave me alone. Another really fun vocalization that gorillas do is called a belch vocalization. And a belch vocalization sounds a little bit like this. [gorilla belching] So particularly when the group is spread out, you'll hear a belch vocalization there and then you'll hear another one over from the bushes over there and they're letting each other know that they're around,
3:13
that everyone is well, and we even use that vocalization when we're approaching the gorillas [belching]
3:19
And it's basically a way to say, I'm here, nothing's wrong, I come in peace. @JohnnyV45385760 asks, "#Primatologists: How accurate are those new planet of the eight movies?" Lots of parts of those movies are accurate. When you look at Caesar and his clear leadership and dominance, that's very typical of chimps where males have hierarchies and there will be a dominant male and his job is to kind of be in charge of the group. When you look at the intellectualism
3:48
of Maurice, the orangutan character, that's very much what orangutans are kind of known for within the primate world. Where there were some inaccuracies, for example, is Bonobos. So Bonobos are represented as being some of the most aggressive and evil characters within the movie, and that's actually not true. Bonobos are probably one of the most peaceful of the great apes. We do need to remember that those apes in the movies were genetically modified apes,
4:12
so they weren't supposed to necessarily represent how apes in the wild behave. @AGus_802, "You know, a non-human primates smile, it's actually a sign of aggression." That is not quite accurate. It is often used in aggressive situations, but it more often is a sign of submission. This is an animal showing one of these fear grimaces or submissive smiles and it doesn't look like it's very comfortable. That's in contrast, say to this chimpanzee that we have here.
4:39
It's a much more relaxed facial expression. The mouth is open, but it's very gentle. So this would be something that I would say you would see when an animal is actually quite calm and probably about to play, but you are correct that teeth are often used in displays of aggression. This is a baboon showing off their teeth and certainly during aggressive displays they'll use them actually to bite and attack other rivals. The other thing is oftentimes they'll combine their teeth
5:04
with other facial expressions to show aggressions. So this is a macaque and you can see is showing off his teeth and then also his eyes are quite big and in macaques we often see they have these lighter eyelids and they'll flash them to let another animal know that they're dominant or they're not happy with their behavior. @IvyGreen asks "LMAO, why do gorillas have two foreheads?" I must admit I have never thought about it that way, but I could easily see where someone might make
5:28
that kind of assumption. So this is a cast of a male gorilla, which we call a silver back. What you see here is you, he's got this heavy brow ridge over his eyes, which I would imagine is what you're thinking is the first forehead. But then what's really neat, and this is actually only found in the male gorillas, is what we call this sagittal crest. It's a bony protrusion. They have these muscles that connect up through here and onto the sagittal crest
5:50
and that's what gives the males amazing jaw strength. Not so much for feeding because gorillas are vegetarians, but they're using it to fight other males, to attract females and defend their families. @asipoftea asks, "If anything attacks us, zombies, aliens, gorillas, I won't know what to do. Ima die." I can't really help you with the zombies or the aliens, but I can tell you about gorillas. First of all, they would hear you way before you would probably hear them
6:15
and they would disappear without you even knowing it. Gorillas unfortunately have not fared well against humans, and so they have a healthy fear of us and they would move out of the way. Now there is an occasion where maybe you could surprise a gorilla, it didn't hear you coming and they will attack, but really it's just to defend themselves. A lot of times it might be a bluff charge where they come at you and they beat their chest. It's very rare and I know of no humans
6:37
that have actually been killed by gorillas, so I don't think you have a lot to worry about there. Chimpanzees on the other hand, are a little bit of a different story and chimps have been known to attack humans and actually to grab human babies that they have found and eat them, but of course they are more meat eaters than gorillas who are purely vegetarians. @earthinspace wants to know, "Why do chimpanzees have wars?" Chimpanzee wars are extremely fascinating.
7:04
Chimpanzees live in these very complicated societies and they're very territorial, chimp males will actually patrol their territories. They get in a single file line, they walk behind each other and they're totally silent, and they will look for other individuals from neighboring communities that might have come into their territory and oftentimes they will actually kill them. What's also really interesting about chimps is sometimes these groups will split.
7:27
When a community splits, they'll go and try and eliminate members from a community that used to be part of their own. @KingKongIn3D asks, "How well do you think Andy Serkis motion captured performed Kong?" There have been many depictions of King Kong, but I think that Andy Serkis' may be the most accurate and in some ways the most soulful. Andy actually came to Rwanda to learn about gorilla behavior from us and we spent lots of time out in the field. I remember one day
7:55
where there were two gorilla brothers playing and they were having a great time and they were laughing and Andy captured that on film and you can see in this clip where Kong is playing with Naomi Watts's character and he's also laughing a sort of a chuckle, and that's exactly what we see gorillas do in the wild and Andy had the opportunity to watch these two brothers playing and doing this exact behavior. And so it was lovely to see that natural gorilla behavior end up in the Kong film.
8:19
@sheepkinta asks, "You know, I have no idea where any monkeys or apes live. I always assumed it was a jungle." Well, you assumed correctly. The new world monkeys live in the tropical forests of central and South America. Then you have your old world monkeys and they are found in the tropical forests of Asia and Africa. But interestingly, they don't only confine themselves to tropical forests. We have the amazing Japanese macaques which live in the mountains and are often seen in snow
8:45
and they love to go into these hot pools and basically just like us sit in a hot pool and enjoy a relaxing afternoon of getting warm. And then when you come to Africa, this is where we have multiple species of great apes. Bonobos are found in only a single country. Right here, the Democratic Republic of the Congo. These drawings are approximate, but this is the only place that Bonobos are found. Then we go to the gorillas. There are the eastern species. They have a very small range over here
9:11
in the countries of Rwanda, Congo and Uganda. They're big, they're hairy because they actually live at high elevations where it is quite cold. And then you've got the western gorillas. They live here in countries like Cameroon, Nigeria, Equatorial Guinea, the Republic of Congo. Finally you have chimpanzees. They have the largest distribution of any of the African great apes, so they start all the way over here in Tanzania and can come all the way to the west coast in Senegal.
9:38
The one great ape that I haven't mentioned is US humans and we are obviously found on every continent on the planet. @maybeitsgrace asks, "Why do orangutans look like that?" This is a fully adult, a male orangutan, and they have these, we call them cheek pads or flanges on either side of their face. These are male secondary sexual characteristics. We don't see them in females. A male orangutans make these incredible long calls because they're solitary for the most part,
10:07
these cheek pads may help sort of broadcast that message out there. It's likely also one of the characteristics that females use when they're picking a mate. Some of male orangutans can choose to not develop these characteristics and they can actually stay in a form that looks more like a female. And what this means is that they'll often be tolerated by the adult males in the area, maybe because they don't recognize them as a male and it's competition.
10:31
If there is a male like this in the vicinity and he disappears, maybe he moves off or dies. These males that have the more female morphology can then develop into a fully flanged adult male. Orangutans are the most are boreal of the great apes. They spend lots of time in trees, so they have these long arms that can help them move between tree to tree and they have these enormous hands and their thumb is placed pretty far back on their hand. It just gives them more space to be able
10:58
to grab onto large tree branches than if their thumb was kind of a bit higher up like ours is. @TinctureDrone asks, "Our most primates, monogamous or not." There are some species that we see in central and South America called marmosets and tamarinds. They're often monogamous. Most primates, however, are not monogamous. And the two reproductive strategies we see most of the time, one is polygene and that is where one male will meet with multiple females.
11:22
The silver back male of the group generally mates with all of the females, and then you have a promiscuous mating structure and that is where both males and females were mate with multiple members of the opposite sex. That is commonly seen in chimpanzees, for example, in baboons by mating with multiple males, you're confusing paternity that no one male knows he is the sire of that offspring and so hopefully all of them will be invested in helping to make sure that that offspring stays safe.
11:48
@grahkayyy asks, "How do gibbons choose their mates?" What we do know for gibbons is that they are one of the few primate species that are monogamous. So males and females will spend long periods of time living together. They do something called dueting, which is an absolutely beautiful sound. The duet involves both of them singing together, making this very unique sound that can be heard for long distances through the forest. Here's an example actually of a given duet. [gibbons dueting]
12:17
It is definitely one of the most unique vocalizations that we hear in the primary world. @Element_82 wants to know, "Why do gorillas get to be so ripped from eating leaves and not lifting not fair?" Gorillas are the largest primate on the planet. Male gorillas can weigh around 400 pounds, and you are right, they are ripped a 100% muscle, so they do only eat plants and plants do have a lot of protein, but they do have an extra advantage that we don't and that's their digestive system.
12:44
So they have a much larger intestines than us and particularly the large intestines is bigger than us and they do something called hind gut fermentation. There are microbes in their digestive system that are helping them break down that fibrous plant material in a better way than just their own enzymes can do. And it means that they're able to extract more nutrients out of plants than we would actually be able to. One of the questions that I get asked most frequently about gorillas is like,
13:10
how strong are they compared to humans? And I don't really know that we have the definitive answer. What I hear out there is that they are roughly 10 times as strong as we are. So this is a replica of a male gorilla hand. It's true to size. You can see how actually enormous their hands are. @SDF4041SDF404 asks, "What are the social structures
13:32
and hierarchies within primate groups like monkeys and apes?" Within primate social groups, there's generally always hierarchies. Bigger males are often the ones that end up becoming dominant. They use a lot of those secondary sexual characteristics, the big canine teeth, the large size to fight for access to dominance, and they wanna be dominant because that's what gets them the opportunities to breed. In gorillas, for example, we will have one very large male,
13:56
the silver bag, his job is to protect the group. It's to decide where the group's gonna go. In other primate groups, you might find that females are actually dominant and we see that in Bonobos. Baboon females stay in the group they were born in for their entire lives, so they've got all their female relatives around them and they organize and match in lines. So if your mom is the dominant female and you're a tiny little baby baboon, you'll be dominant over all the other females in that group
14:20
because guess who's backing you up, should someone pick on you? Your mom, who is the dominant female. @AutumnLupin asks, "Do primates have culture? I don't know, I'm not a primatologist." Well, I am a primatologist and I can say that yes, primates do indeed have culture. Culture are behaviors or traits that have been passed down, not through genetics, but learned from one generation to another. One great example that I love from chimpanzees is this behavior called leaf clipping.
14:47
So a chimpanzee will put a leaf in their mouth and then rip it. In one population of chimpanzees, this is an invitation to play and in another population of chimpanzees, it's actually an invitation to have sex. Another example that we see again in chimpanzees is how they groom each other. Instead of just sitting next to an individual and going through their hair, they'll actually put their arms up and class and they'll hold their arms like that while they're doing the grooming.
15:10
And it's very unique to a particular chimp population. @theybian_tm, "I'm gonna be real with you guys. What the fuck is a slow loris?" Slow loris is a prosimian. So these are kind of the most ancestral primates that we have out there. They're found in Asia and they're nocturnal. So those big, big eyes that you see help this animal forage at night by capturing moonlight or other light that may be out in the environment. @Segerdailey says, "Do primates laugh at farts?" Boy, I wish they did
15:39
because they do spend a lot of time farting. In particular gorillas that I work with, they eat. You think about it, 60 pounds of vegetation a day. They're producing a lot of gas, there is a lot of farting, but they pretty much ignore it. I've never seen them laugh at it. It's just a part of what happens on a daily basis for them. Rachel Osiris asks, "What's a prehensile tail?" It is an adaptation where a tail can actually act as an appendage, so you can use it if you're a primate
16:05
to hold onto branches to move. You can think of it as kind of like a fifth arm or leg. Interestingly, they are only found in new world monkeys, so we only see them in species like howler monkeys and spider monkeys. You won't find monkeys that are in Asia or in Africa having this prehensile tail. Instead, their tails are used more for balance. Apes are actually characterized by not having tails. They have a much more balanced sort of upright center of gravity. They walk and walk upright
16:30
and so kneading that tail over time was just as not as necessary as it was for the monkeys that are really confined much more to the trees. @RichLizard asks, "How do chimps understand numerical order? How did they learn it?" There's been a lot of interest in ape cognition in general, and one of the areas that people have studied is their understanding of numerical order and there's a study where they have numbers presented on a screen and they can actually put them in order
16:52
from one to say 18 or 19 or 20. Now we don't really understand what chimps know here. What they could easily learn is just a sequence of orders. This number, number one is always followed by number two. Number two is always followed by number three. But there have been other really interesting studies done that show that they do have an idea of numbers and of numerical concepts. Researchers will put down a choice between a three and a five say, and whichever number the chimpanzee picks,
17:21
another chimpanzee will get that many treats. So if I pick the five, my partner will then get five treats and I will get three treats. Chimps are really good at picking the number that will give them the best treats, which I just think is amazing. @MattPotter79 asks, "Have you seen the footage of the chimp hunting fish with a spear? They have entered the stone age." This I think references back to a video that went kind of viral of a primate using tool.
17:49
This orangutan holding itself out over water and using a stick to manipulate its environment. Allegedly this orangutan had seen some fishermen nearby and was copying their behavior. We have seen orangutans copy very specific behaviors. For example, orangutans in zoos that have seen their keepers do certain cleaning routines, use a bucket, put water in it, get a rag and clean, orangutans that have seen their keepers put a hat on will do the same thing.
18:14
If they're given a hat, they might put it on their head. So that may have happened in this situation. It's certainly not out of the realm of possibility. Tool use is not something new to primates. We've known about tool use now for more than 40 years, and in fact, it was the pioneering work of Dr. Jane Goodall that first showed us that chimpanzees use tools for a variety of things. At the time it was thought that only humans use tools, and it was one of the things that we used to define
18:37
what makes us different from other animals. We soon learned that chimpanzees use tools. They have hunted with spears, they use sticks to fish out termites, they use moss as a sponge to get water. But we also know now that lots of animals use tools. So we see tool use in dolphins. We see tool use in elephants. We see tool use in certain types of birds. @burglahobbit asks, "Good morning everyone. Do any of you know what's the lifespan of a great ape?"
19:04
Great apes generally live to be in their 30s or 40s if you're a gorilla. For the most part in the while, great apes have shorter lifespans than they do in captivity. @BeamBoy asks, "What do apes and gorillas do when they're sad?" One of the saddest things to see is if a gorilla loses its family, they will often do these hooting vocalizations [hooting] Where they're calling out and trying to find other members of their group. One of the amazing things that we see, they have empathy
19:31
and so oftentimes they will come over and they will console them. They will put their arm around them. If they're young, they'll often hug them. We've also seen that when gorillas die, other gorillas will go through a mourning period. So they don't wanna leave the body. They will lay next to the body, they will groom the body. Sometimes they will even push or shove the body a little bit as if to say, why aren't you moving? @Apefellaz asks, "Did you know all great apes are endangered
19:55
and that four of the six are critically endangered?" Yes, sadly, I did know that. Of the 500 species of primates on the planet, two thirds of them are considered endangered and great apes are among the most endangered. So at most we might have a couple hundred thousand chimpanzees, a couple hundred thousand gorillas. The mountain gorillas that I work with in Rwanda, we have a thousand of them left on the planet. That's it. Sumatra and orangutans, 13,000 of them left.
20:23
Bonobos, we estimate between 15,000 and 20,000 of them left. The Nigerian Cameroon chimpanzee, may be less than 10,000. So this is a critical time for great apes because not only are they endangered, but our estimates are of the ones that we have left, we will probably lose half of them within the next 20 years from things like deforestation, climate change and hunting. So it is really sobering situation for apes in the wild. @3BIConceptInc wants to know, "Who was Dian Fossey
20:52
and what is she famous for researching?" Thank you so much for that question. I love to talk about Dian Fossey. She actually founded my organization. So Dian Fossey is a woman that went in 1967 to Rwanda to study the them pretty much unknown mountain gorilla. She didn't have a scientific background, but she loved animals. And what Dian Fossey did was get accepted into Gorilla Society and told the world the story of them and their amazing social life, how family oriented they are,
21:21
and changed our perception from ferocious beast to gentle giant. These are the gorillas that she knew. They all had individual names, and what's amazing is they all have individual nose prints the same way we have individual fingerprints and that is how she identified them. Down here we have Shaugaza. Shaugaza was born in 1982. She's actually a gorilla that I had the opportunity to study as well when I started working with the Dian Fossey Gorilla Fund.
21:46
So it was real honor for me to be able to study some of the same gorillas that have been studied by Dian Fossey. When Dian Fossey went to Rwanda, she quickly saw that these animals were endangered, they were being killed for trophies. People thought it was cool to have a gorilla head on their mantle or a gorilla hand as an ashtray. And so in addition to the research, she started doing what she called active conservation, which was going in and removing snares. They're sort of set on a branch.
22:10
When the gorilla walks through them, they pull and they catch the gorilla's arm. We remove thousands of these a year to help protect gorillas and other wildlife for getting caught. But this work originally started with Dian Fossey. She was afraid that mountain gorillas would be extinct by the year 2000. Instead, right now, they are the only great ape on the planet besides ourselves that are increasing in number. So those are all our questions for today.
22:33
I love hearing how interested you are in primates. You heard that they need our help, so please get involved and thank you so much for watching APE Support. [upbeat music]
Here to help you learn
Sign in to keep a private conversation with your course tutor.
Ask me anything about the material…
Sign in to chat