Hello in this video, we will talk about big mammals. First of all, we will define them. We will discover why is important to conserve them and we will go in depth into some stories about conservation of big mammals. Big mammals are also called megafauna are those animals that are large or giant, and usually they are bigger than humans. But they can also be defined as those carnivores of more than 15 kilos. In this picture, lion or omnivores of more than 100 kilos. In this picture, the elephant. Megafauna are usually on the top of the food web. In this example, we can find for example blue or killer whales and leopard and elephant seals which are megafauna because they are on the top of the food web. They have usually few natural predators and they have also lower mortality. They can have also lower mortality because of their size also. They are generally K-strategist species, which means that they produce fewer offspring. But these offspring have higher survival rates and usually they arrived into the the adult hood. This is species when species are K-strategist, they have usually high longevity and this low mortality. However, they have slow population growth rates, and this it's important when the species are threatened because they are more vulnerable than other species. The laws of megafauna species is particularly concerning for several reasons. First, because they are of significant and cultural societal value and they are some species that are charismatic. For example, everybody knows which are giant pandas and we know that this kind of charismatic species are prone to gener some interest for people. And people will have more interest to pay for conservation programs. The laws of megafauna species is particularly concerning for several reasons. First of all, because megafauna are of significant cultural and societal values for humans because they are charismatic species. For example, giant panda is a charismatic species and engender interest and willingness to pay for their conservation actions, which is a good point to start for conservation actions. Second, megafauna are of play particularly important roles in ecosystem. For example, they are key in predator-prey cycles, nutrient cycles, and seed dispersal. For example, when a blue whale dead, they gener a lot of nutrients available for a high number of different species in the sea third. It is also important to conserve megafauna because they have significant economic value. For example, in some countries of Africa such as Kenya, Botswana, or South Africa, the gross domestic product of these countries are highly influenced by the tourist that came into those countries for observe this kind of species, this megafauna species. Finally, it is also important to conserve big mammals because they require large areas for conservation. And they can act as a umbrella species which means that by conserving for example, tiger, we can also conserve their habitat. So all the plants invertebrates, reptiles, and amphibians that they live in the same place as as the tiger. Now, we will start with the stories of conservation of big mammals and we will start with elephants. In the world, we have to recognize species of elephants. One is the African elephant, which is considered for the IUCN as being vulnerable. And the other one is the Asian elephant, which is considered for the IUCN as being endangered. Both species African and Asian elephants share some of the threats, which are for example hunting, the fire, Civil War, and poaching. Now, we'll talk about African elephants conservation. And for this we should talk about Joyce Poole, when she only had 19 years old. She join a long-term study of elephants carried out by Cynthia Moss in Amboseli National Park in Kenya. When she was there, she was following some individuals, and only two years later she did a very important discovery, which was the musth. The musth is a period of highly sexual and aggressive behavior that display display major males. This was an important finding because it was the first time that was discovered in African elephants. And she and Cynthia Moss wrote a scientific paper that was published in nature explaining these findings. This finding was also important because Joyce also found that ivory poaching destroys elephant society because tusks are usually used for for the musth period. And because of this the the international trade of ivory was promoted to stop or to try to stop the the elephant poaching. Then Joyce continue working with elephants and indeed she has been working during almost 40 years. In 1982, she defended her PhD with the main subject of elephant behavior. Then during her career, she also find all the other important discoveries, such as the elephant vocalizations and also vocal imitation. Then since 2002, she's the director of the NGO ElephantVoices, which is dedicated to the study of elephants in nature. And also to promote some conservation actions and management of elephants to prevent them from the extinction. [MUSIC]