The Elephant Listening Project is a research group in the Center for Conservation Bioacoustics at the Cornell Lab of Ornithology. Founded in 1999 by Katy Payne, the project focuses on the biology and conservation of the African forest elephant (Loxodonta cyclotis), a species inhabiting the rainforests of central and west Africa.
The concept behind the Elephant Listening Project began to form in 1984 when Katy Payne was observing Asian elephants in the Portland Zoo and began to suspect that elephants communicate using infrasonic frequencies, frequencies below what humans can hear. Carl Hopkins and Bob Capranica, acoustic biologists at Cornell University, encouraged Payne to return to Portland with specialized recording equipment to gather additional data. After four months in Portland with colleagues William Langbauer and Elizabeth Thomas, she had the evidence she needed. [1] Payne was aware of observations of families of African savannah elephants (Loxodonta africana) apparently coordinating their movements even when separated by several kilometers. [2] [3] Payne's insight was that perhaps the infrasonic frequencies of elephant calls could be heard even kilometers away and so used to coordinate movements and behavioral interactions. Through a series of field experiments with numerous collaborators, Payne was able to demonstrate that this was in fact the case. [4] [5] [6] In 1999, Payne published her elephant discoveries in her book, Silent Thunder. [7]
Late in the 1990s, considerable conservation concern was growing about the poorly known forest elephant, at the time considered a subspecies of the savannah elephant. Another of Payne's insights was that these difficult-to-observe animals might be studied by listening to their low-frequency vocalizations, even where they could not be seen. The result was the founding of the Elephant Listening Project at the Laboratory of Ornithology in 1999.
From the beginning, the Elephant Listening Project collaborated closely with Andrea Turkalo, the world expert on forest elephant social biology. Her work at the Dzanga Bai (a forest clearing) in the Central African Republic, which began in 1990 and continued until 2017, forms the foundation of our knowledge of forest elephant demography. [8] [9] In 2000, Payne and colleagues began the first studies of acoustic communication in forest elephants, culminating in several key publications that remain the foundation of the landscape-scale acoustic monitoring conducted by the Elephant Listening Project today. [10] [11]
In 2005, Katy Payne retired and Peter Wrege took over the project. With the continued devastating decline of forest elephant populations due to poaching and human population growth, Wrege turned the focus of the Elephant Listening Project to using acoustic tools for applied conservation. [12] [13] [14] [15] Primary among these has been implementing landscape-scale passive acoustic monitoring (PAM) projects to discover the details of how forest elephants use different habitats, where they engage in social interactions within the forest, and how they respond to human intrusion. The largest of these studies is in the Nouabalé-Ndoki National Park in northern Republic of Congo, monitoring 1250 km2 of rainforest. More than one million hours of forest sounds have been recorded, including elephant rumbles and poacher's gunshots. The recordings from this ongoing study have been made publicly available in the hope that other conservationists will utilize this unique resource.
Beginning in 2020, the Elephant Listening Project, in partnership with the World Wide Fund for Nature (WWF) began managing elephant research at the Dzanga Bai in the Central African Republic. The focus of this effort is to build on the unparalleled historical knowledge of individually-recognized elephants gathered by Andrea Turkalo. Turkalo identified more than 4,000 individual elephants and tracked their family relationships, social behavior, history of visits to the clearing, and reproduction, often from birth to adulthood. These data provide the most complete source of material available for understanding forest elephant demography and behavior. [16] [17] [18]
Elephants are the largest existing land animals. Three living species are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. They are an informal grouping within the proboscidean family Elephantidae. Elephantidae is the only surviving family of proboscideans; extinct members include the mastodons. Elephantidae also contains several extinct groups, including the mammoths and straight-tusked elephants. African elephants have larger ears and concave backs, whereas Asian elephants have smaller ears, and convex or level backs. Distinctive features of all elephants include a long proboscis called a trunk, tusks, large ear flaps, massive legs, and tough but sensitive skin. The trunk is used for breathing, bringing food and water to the mouth, and grasping objects. Tusks, which are derived from the incisor teeth, serve both as weapons and as tools for moving objects and digging. The large ear flaps assist in maintaining a constant body temperature as well as in communication. The pillar-like legs carry their great weight.
Infrasound, sometimes referred to as low-frequency sound, describes sound waves with a frequency below the lower limit of human audibility. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high. The ear is the primary organ for sensing low sound, but at higher intensities it is possible to feel infrasound vibrations in various parts of the body.
The African forest elephant is one of the two living African elephant species. It is native to humid forests in West Africa and the Congo Basin. It is the smallest of the three living elephant species, reaching a shoulder height of 2.4 m. Both sexes have straight, down-pointing tusks, which erupt when they are 1–3 years old. It lives in family groups of up to 20 individuals. Since it forages on leaves, seeds, fruit, and tree bark, it has been referred to as the 'megagardener of the forest'. It contributes significantly to maintain the composition and structure of the Guinean Forests of West Africa and the Congolese rainforests.
The Asian elephant, also known as the Asiatic elephant, is the only living species of the genus Elephas and is distributed throughout the Indian subcontinent and Southeast Asia, from India in the west, Nepal in the north, Sumatra in the south, and to Borneo in the east. Three subspecies are recognised—E. m. maximus from Sri Lanka, E. m. indicus from mainland Asia and E. m. sumatranus from the island of Sumatra.
The African elephant (Loxodonta) is a genus comprising two living elephant species, the African bush elephant and the smaller African forest elephant. Both are social herbivores with grey skin, but differ in the size and colour of their tusks and in the shape and size of their ears and skulls.
The Sri Lankan elephant is one of three recognised subspecies of the Asian elephant, and native to Sri Lanka. Since 1986, Elephas maximus has been listed as endangered by IUCN as the population has declined by at least 50% over the last three generations, estimated to be 60–75 years. The species is primarily threatened by habitat loss, degradation and fragmentation.
The giant forest hog, the only member of its genus, is native to wooded habitats in Africa and is generally considered the largest wild member of the pig family, Suidae; however, a few subspecies of the wild boar can reach an even larger size. Despite its large size and relatively wide distribution, it was first described only in 1904. The specific name honours Richard Meinertzhagen, who shot the type specimen in Kenya and had it shipped to the Natural History Museum in England.
Katharine Boynton "Katy" Payne is an American zoologist and researcher in the Bioacoustics Research Program at the Laboratory of Ornithology at Cornell University. Payne studied music and biology in college and after a decade doing research in the savanna elephant country in Kenya, Zimbabwe, and Namibia, she founded Cornell's Elephant Listening Project in 1999.
Vachellia xanthophloea is a tree in the family Fabaceae, commonly known in English as the fever tree. This species of Vachellia is native to eastern and southern Africa. It has also become a landscape tree in other warm climates, outside of its natural range.
Prusten is a form of communicative behaviour exhibited by some members of the family Felidae. Prusten is also referred to as chuffing or chuffle. It is described as a short, low intensity, non-threatening vocalization. In order to vocalize a chuff, the animal's mouth is closed and air is blown through the nostrils, producing a breathy snort. It is typically accompanied by a head bobbing movement. It is often used between two cats as a greeting, during courting, or by a mother comforting her cubs. The vocalization is produced by tigers, jaguars, snow leopards and clouded leopards. Prusten has significance in both the fields of evolution and conservation.
The African bush elephant, also known as the African savanna elephant, is one of two living African elephant species. It is the largest living terrestrial animal, with bulls reaching a shoulder height of up to 3.96 m (13.0 ft) and a body mass of up to 10.4 t . It is distributed across 37 African countries and inhabits forests, grasslands and woodlands, wetlands and agricultural land. Since 2021, it has been listed as Endangered on the IUCN Red List. It is threatened foremost by habitat destruction, and in parts of its range also by poaching for meat and ivory. It is a social mammal, travelling in herds composed of cows and their offspring. Adult bulls usually live alone or in small bachelor groups. It is a herbivore, feeding on grasses, creepers, herbs, leaves, and bark.
The Dzanga-Sangha Special Reserve is a protected reserve of southwestern Central African Republic. It was established in 1990 and covers 6865.54 km2. It is one of several areas within the Dzanga-Sangha Complex of Protected Areas (DSCPA), each within its own protective status and along with Lobéké National Park in Cameroon and Nouabalé-Ndoki National Park in Republic of Congo, it is part of the Sangha Trinational Landscape. Other areas within the DSCPA include the Dzanga Ndoki National Park which has two sectors, the 495 km2 (191 sq mi) Dzanga park and the 725 km2 (280 sq mi) Ndoki park. A conference of the Ministers of Forests of Central African Forest Commission (COMIFAC) had resolved to establish within the Congo basin, the Sangha River Tri-national Protected area (STN) encompassing these three parks. The forest special reserve is operated by the Central African Forest Commission (COMIFAC).
The Dzanga-Ndoki National Park is located in the southwestern extremity of the Central African Republic. Established in 1990, the national park is 1,143.26 square kilometres (441.42 sq mi). The national park is split into two non-continuous sectors, the northern Dzanga sector 49,500 ha and the southern Ndoki sector 72,500 ha. Notable in the Dzanga sector is a gorilla density of 1.6/km2 (4.1/sq mi), one of the highest densities ever reported for the western lowland gorilla.
Seismic or vibrational communication is a process of conveying information through mechanical (seismic) vibrations of the substrate. The substrate may be the earth, a plant stem or leaf, the surface of a body of water, a spider's web, a honeycomb, or any of the myriad types of soil substrates. Seismic cues are generally conveyed by surface Rayleigh or bending waves generated through vibrations on the substrate, or acoustical waves that couple with the substrate. Vibrational communication is an ancient sensory modality and it is widespread in the animal kingdom where it has evolved several times independently. It has been reported in mammals, birds, reptiles, amphibians, insects, arachnids, crustaceans and nematode worms. Vibrations and other communication channels are not necessarily mutually exclusive, but can be used in multi-modal communication.
Infrasound is sound at frequencies lower than the low frequency end of human hearing threshold at 20 Hz. It is known, however, that humans can perceive sounds below this frequency at very high pressure levels. Infrasound can come from many natural as well as man-made sources, including weather patterns, topographic features, ocean wave activity, thunderstorms, geomagnetic storms, earthquakes, jet streams, mountain ranges, and rocket launchings. Infrasounds are also present in the vocalizations of some animals. Low frequency sounds can travel for long distances with very little attenuation and can be detected hundreds of miles away from their sources.
Langoué Baï, located in Ivindo National Park, is the largest baï in Gabon, and covers 12.5 ha, with a length of 850 m and a width of 350 m. Archaeological findings show human habitation of other nearby clearings as recently as 4000 BP, and of the area around the current Ivindo train station and around the park in general from as early as 120,000 BP to the modern day. The baï itself was rediscovered in 2001 by Mike Fay during the Megatransect, who recognised its significance and importance for wildlife, calling it the "most important discovery" of the 2000 mile hike through Congo and Gabon.
The TarangireEcosystem is a geographical region in Africa. It is located in northern Tanzania and extends between 2.5 and 5.5 degrees south latitudes and between 35.5 and 37 degrees east longitudes.
Lomami National Park is a national park located in the Democratic Republic of Congo in Central Africa. Situated within the middle basin of the Lomami River, it straddles the Provinces of Tshopo and Maniema with a slight overlap into the forests of the Tshuapa and Lualaba river basins. The National Park was formally declared on 7 July 2016. It is the 9th national park in the country and the first to be created since 1992.
Grewia hexamita, the giant raisin, is a species of flowering plant in the family Malvaceae, native to Mozambique and adjoining countries. It is a large tree for a Grewia, reaching 5 m (16 ft). It is the most preferred woody plant of African savanna elephants, who browse on it in all seasons, unlike even other species of Grewia.
Elephants communicate with each other in various ways, including touching, visual displays, vocalisations, and seismic vibrations.
