Tag Archives: #elephants

Researchers Locate Elephants Using Microphones-Siesmometers Combination (Biology)

Researchers from the University of Oxford, Mpala Research Center and Save the Elephants, have used a combination of acoustic microphones and seismometers to locate elephants.

In this novel study, published today in The Journal of the Royal Society Interface, researchers managed to accurately determine elephant locations by measuring the vibration of the ground caused by their rumbles, which are low frequency calls. To do this, they used seismometers, which are seismic sensors typically used for measuring earthquakes and explosions.

Seismic waves pass through lots of different solid materials between source and sensor, unlike the acoustic waves. It was a surprise that the seismic sensors worked just as well as the acoustic sensors to localise the elephants, and in some cases they worked even better

This interdisciplinary research, created in collaboration with computer scientists, earth scientists, conservationists, and biologists, used data gathered in Kenya, and is the first study to use seismometers to get locational information about elephants in the wild. Acoustic and seismic equipment was set up around a watering hole known to be frequented by elephants at the Mpala research center in Kenya, and paired with camera traps to provide additional data. Researchers discovered that the seismic dataset led to a more accurate localisation of elephants than the acoustic dataset.

Previous work has shown that seismic recordings can be used to differentiate between elephants’ activities such as walking, running and calling. But seismic monitoring also provides information about other animals and their activities. In future work, the team hopes to develop ”listening rules” to detect what wildlife is close to these sensors and what they are doing, all based on their seismic “footprints”.

Dr Michael Reinwald, postdoctoral researcher at Oxford’s Department of Zoology, said: ‘Seismic waves pass through lots of different solid materials between source and sensor, unlike the acoustic waves. It was therefore a surprise that the seismic sensors worked just as well as the acoustic sensors to localise the elephants, and in some cases the seismic systems worked even better.’

From a conservation perspective, using seismic sensors alongside acoustic systems offers an alternative, and potentially more accurate, way of assessing situations. Where acoustic recordings would be influenced by rain, wind, and both human and animal activity, seismic monitoring would be impacted by other factors, such as geology and sensors are buried under the ground.

This is useful because it allows conservationists to have more data on where elephants are in different scenarios. Knowing whether or not elephants are present in protected areas, or if they’re going into environments with higher risks, allows for reactive responses, and can limit human-elephant conflict.

PI Dr Beth Mortimer from the Department of Zoology said, “This study is important as it shows that seismic information from elephant rumble calls is just as useful as acoustic information for locating elephants. This opens up further questions about how the elephants might be using seismic rumbles to communicate with each other in the wild.”

Moving forward, this allows researchers to develop novel and innovative ways to monitor elephant movement. This real time detection and localisation of both elephants and other wildlife will allow for more appropriate anti-poaching intervention and limiting wildlife-human conflicts.

Featured image: Poaching claims an estimated 8% of African elephants each year, or around 96 elephants per day. © Shutterstock

Reference: Michael Reinwald et al., “Seismic localization of elephant rumbles as a monitoring approach” JRSI, Published:14 July 2021. https://doi.org/10.1098/rsif.2021.0264

Provided by University of Oxford

Asian Elephants Do More Than Just Trumpet- They Buzz Their Lips to Squeak (Biology)

The animals’ sound production does not only come from the trunk

Communication is crucial for elephants that live in complex multi-tiered social systems. Apart from their iconic trumpets uttered through the trunk, Asian elephants also produce species-specific squeaks by buzzing their lips. This demonstrates once again the elephant’s flexibility in sound production. These results are presented in a publication in “BMC Biology” by behavioural biologist Veronika Beeck from the University of Vienna and colleagues.

Everybody from a child knows that elephants trumpet. Over the past decades research in general and at the University of Vienna has mainly studied the elephants low-frequency rumble. Its fundamental frequency reaches into the infrasonic range below the human hearing threshold. This call is produced by the elephant´s massive vocal folds. Much less was known about how elephants produce their higher pitched sounds, trumpets and squeaks.

The following rule generally applies to sound production in mammals: the larger the vocal fold, the lower the calls fundamental frequency. Conversely the size of the vocal folds sets an upper limit to the fundamental frequencies that can be reached. The high-pitched squeak only Asian but not African elephants produce when aroused, do not fit within that spectrum.

In her recent study Veronika Beeck, who is part of the FWF doctorate school Cognition and Communication at the Department of Behavioural and Cognitive Biology at the University of Vienna and her supervisor Angela Stöger, together with Gunnar Heilmann and Micheal Kerscher from gfai tech, Berlin, studied the squeak sounds of Asian elephants in Nepal.

The researchers used an acoustic camera with an array of 48 microphones that visualises sounds in colours similar to a thermic camera. In this way the sound source was precisely located. “Our images clearly demonstrate that the squeaks are emitted by the mouth and not the trunk”, Veronika Beeck explains. 

According to the researcher’s theory the Asian elephants produce squeaks by pressing air through their tensed lips inducing the lip´s vibration. This technique equals the human brass players lip buzzing to produce a complex sound whose harmonic overtones are subsequently resonated by the instrument, resulting in its characteristic brassy sound. “Apart from human brass players this technique of lip buzzing to produce sounds has, to our knowledge, not been described in any other animal species and is thus considered unique in the animal kingdom”, says Veronika Beeck.

The elephants iconic trumpet on the other hand is produced by a blast of air through the trunk. Here again, however, the vibrating anatomic sound source is not yet conclusively studied.

This new evidence further highlights the elephant´s flexibility in sound production. A few years ago, Angela Stöger-Horwath showed that elephants are capable of learning novel sounds. An Asian elephant in a Korean Zoo, by imitating his trainer, learned to speak some words in Korean. Since only a few elephants in this recent study squeaked the researchers suggest that squeaks might be learned, too.

Featured image: With the acoustic camera´s star-shaped array of microphones placed in front of the elephant the researchers are waiting patiently for her to vocalize while night falls. (© Gunnar Heilmann)

Publication in BMC Biology:

  • A novel theory of Asian elephant high-frequency squeak production.
  • Veronika C. Beeck, Gunnar Heilmann, Michael Kerscher, Angela S. Stoeger
  • DOI: BMCB-D-20-01049

Provided by University of Wien

How Elephants Evolved to Become Big and Cancer-resistant? (Biology)

A study shows that elephants possess a large toolbox of genes for evading cancer, and suggests that evolution of tumor suppression capabilities contributed to the development of big bodies

All things being equal, large, long-lived animals should have the highest risk of cancer.

The calculation is simple: Tumors grow when genetic mutations cause individual cells to reproduce too quickly. A long life creates more opportunities for those cancerous mutations to arise. So, too, does a massive body: Big creatures — which have many more cells — should develop tumors more frequently.

Why, then, does cancer rarely afflict elephants, with their long lifespans and gargantuan bodies? They are some of the world’s largest land animals.

A new study delves into this sizeable mystery, showing that elephants possess extra copies of a wide variety of genes associated with tumor suppression.

But this phenomenon is not unique to elephants, scientists say: The research concluded that duplication of tumor suppressor genes is quite common among elephants’ living and extinct relatives, including in small ones like Cape golden moles (a burrowing animal) and elephant shrews (a long-nosed insectivore). The data suggest that tumor suppression capabilities preceded or coincided with the evolution of exceptionally big bodies, facilitating this development.

The study was published on Jan. 29 in the journal eLife by biologists Vincent Lynch at the University at Buffalo and Juan Manuel Vazquez at the University of California, Berkeley.

“One of the expectations is that as you get a really big body, your burden of cancer should increase because things with big bodies have more cells,” says Lynch, PhD, assistant professor in the Department of Biological Sciences in the UB College of Arts and Sciences. “The fact that this isn’t true across species — a long-standing paradox in evolutionary medicine and cancer biology — indicates that evolution found a way to reduce cancer risk.”

In the new study, “We explored how elephants and their living and extinct relatives evolved to be cancer-resistant,” Lynch says. “We have past research looking at TP53, a well-known tumor suppressor. This time, we said, ‘Let’s just look at whether the entire elephant genome includes more copies of tumor suppressors than what you’d expect.’ Is the trend general? Or is the trend specific to one gene? We found that it was general: Elephants have lots and lots and lots of extra copies of tumor suppressor genes, and they all contribute probably a little bit to cancer resistance.”

Elephants do have enhanced cancer protections, compared with relatives

Though many elephant relatives harbor extra copies of tumor suppressor genes, the scientists found that elephant genomes possess some unique duplications that may contribute to tumor suppression through genes involved in DNA repair; resistance to oxidative stress; and cellular growth, aging and death.

“By determining how big, long-lived species evolved better ways to suppress cancer we can learn something new about how evolution works and hopefully find ways to use that knowledge to inspire new cancer treatments,” says Vazquez, PhD, a postdoctoral researcher at UC Berkeley who completed much of the project while earning his PhD at the University of Chicago.

A related mystery: How did giant sloths and ancient mega-armadillos get so big?

Artist’s illustration of species within the taxonomic order Proboscidea, which includes elephants. Credit: Liam Elward

Elephants are a great case study for understanding the evolution of cancer protection because they belong to a group of mammals — the Afrotherians — that are mostly small-bodied.

The study searched for extra copies of tumor suppressor genes in the DNA of Asian, African savanna and African forest elephants, as well as in the genomes of a number of fellow Afrotherians, such as Cape golden moles, elephant shrews, rock hyraxes, manatees, extinct woolly mammoths, extinct mastodons and more. The team also studied certain species belonging to a group of mammals called Xenarthra that is closely related to Afrotherians, and found some extra copies of tumor suppressors in those animals’ genomes as well.

Given the findings, Lynch wonders whether the duplication of tumor suppressors may have aided the evolution of other ancient large bodies within these groups.

“If you pick a weird mammal, there’s a good chance that it will be in these groups, the Afrotherians and Xenarthrans: armadillos, aardvarks, sloths, anteaters, all of these weird mammals,” Lynch says. “We found that within these groups of organisms, the ones we studied all seem to have extra copies of tumor suppressor genes. That may be why in the last Ice Age, there were giant sloths and ancient mega-armadillos. There’s even an extinct species of manatee relative called the Steller’s sea cow that was elephant-big. Extra copies of tumor suppressors may have helped all of these animals get really, really big.”

Featured image: Artist’s illustration of species within the taxonomic order Proboscidea, which includes elephants. Credit: Liam Elward

Reference: Juan M Vazquez, Vincent J Lynch et al., “Pervasive duplication of tumor suppressors in Afrotherians during the evolution of large bodies and reduced cancer risk”, eLife, 2021. DOI: 10.7554/eLife.65041

Provided by University at Buffalo

Strangers In The Night – A New Spe­cies of Mam­mal May Have Been Found in Africa’s Mont­ane Forests (Biology)

A research team from the University of Helsinki has discovered a tree hyrax in the Taita Hills, Kenya, which may belong to a species previously unknown to science.

The tree hyrax song may continue for more than twelve minutes, and it consists of different syllables that are combined and repeated in various ways. © Photo: Hanna Rosti

The discovery, which was part of a study of the vocalisations of nocturnal animals in the Taita Hills, was published in mid-December in the scientific journal Discovery.

Very little is known about the diversity and ecology of tree hyraxes because these animals, which look like large guinea pigs but are distant relatives of elephants, are mainly active at night in the tree canopies in Africa’s tropical forests. These animals are known to be able to scream with the strength of more than one hundred decibels, but the ‘strangled thwack’ calls that have been recorded in Taita’s forests have not been described anywhere else.

The re­cord­ings re­veal that the Taita tree hyraxes sing

The tree hyrax song may continue for more than twelve minutes, and it consists of different syllables that are combined and repeated in various ways.

“The singing animals are probably males attempting to attract females that are willing to mate,” postulates Hanna Rosti, who spent three months in Taita’s forests, following the nocturnal mammals and recording their vocalisations.

The results suggest that the two populations of dwarf galago in the Taita Hills may belong to different species. The calls of the animals of the smaller population are very similar to those of the Kenya coast dwarf galago, a species that has previously been thought to live only in coastal, low elevation forests. The peculiar calls of the second population cannot yet be linked with certainty to any known species.

“The taxonomy of many nocturnal mammals remains poorly known, and many populations have not been studied at all yet,” says researcher Henry Pihlström, who reviewed the complex taxonomy of tree hyraxes and galagos for the published study.

References: Rosti, H.; Pihlström, H.; Bearder, S.; Pellikka, P.; Rikkinen, J. Vocalization Analyses of Nocturnal Arboreal Mammals of the Taita Hills, Kenya. Diversity 2020, 12, 473. https://www.mdpi.com/1424-2818/12/12/473?fbclid=IwAR1FKcHvJBL0lHIx2_QnzAztX-vLbhjvew6DePmtq2Rqs4Qo23M8Tf9SupQ

Provided by University of Helsinki

Why Do Elephants and Tigers Still Roam in India? Study Offers Clues (Biology)

Tropical Asia and Africa are the only regions on Earth that retain diverse populations of large, land-dwelling mammals, such as elephants, rhinos, and big cats. A new study co-authored by Yale researcher Advait M. Jukar suggests that the persistence of mammalian megafauna in the Indian Subcontinent is related to the great beasts’ long coexistence there with homo sapiens and other human ancestors.

©University of Yale

The study, published in the journal Palaeogeography, Palaeoclimatology, Palaeoecology — and based on a novel dataset drawn from 51 fossil sites in present-day India — documents a low-magnitude extinction that began about 30,000 years ago. That was about 30,000 years after modern humans arrived in the Indian Subcontinent.

The analysis provides the first direct and independent test of the “co-evolution hypothesis,” a commonly held theory that the magnitude of an extinction correlates with the amount of time that large mammals coexist with humans and their hominin ancestors, the researchers said. 

Our work supports the idea that some large species co-evolved with human ancestors, adapting to their presence [and behaviors].”, said Advait m. Jukar.

“During the past 100,000 years, people have been implicated in the extinction of large, land-dwelling mammals all over the world, but Indian megafauna proved more resilient and, as in Africa, have co-existed with humans for much longer periods than in other regions,” said Jukar, a Gaylord Donnelly Postdoctoral Associate at the Yale Institute for Biospheric Studies and the study’s lead author. “Our work supports the idea that some large species co-evolved with human ancestors, adapting to their presence and developing behaviors that helped them cope with how they altered the habitat.” 

Jukar co-authored the study with S. Kathleen Lyons and Peter J. Wagner of the University of Nebraska-Lincoln, and Mark D. Uhen of George Mason University.  

Not all large mammals on the Indian Subcontinent survived, of course. The researchers document the extinctions of Palaeoloxodon namadicus and Stegodon namadicus, two species of elephant; Hexaprotodon sp., a hippopotamus; and Equus namadicus, a zebra-like horse. They also show the extirpation, or local extinction, of ostriches, which survive elsewhere, and the “pseudo-extinction” of the Indian aurochs — the wild ancestor of the domestic zebu cattle that thrive in India today. The four extinctions represent about 4% of mainland India’s mammalian fauna and 20% of its mammalian megafauna, animals weighing more than 50 kilograms, or 110 pounds. Human activity combined with the species’ limited ranges and slow reproduction rates contributed to these extinctions, Jukar said.

The extinction rate in India over the past 50,000 years is comparable to that of eastern and southern Africa, but 2.5 times smaller than in South America and 4 times smaller than in North America, Europe, Madagascar, and Australia, according to the study. The researchers noted that India’s extinction pattern is strikingly similar to that of Africa, where humans first evolved, lending support to the co-evolution hypothesis. (The first hominins— a group that includes modern humans and all our immediate ancestors — arrived in India about 1.7 to 1.5 million years ago.) The researchers conclude that, as in Africa, land-dwelling megafauna provided remarkably resilient to human pressures. They found that the presence of other hominins had little to no impact on the Indian Subcontinent’s animal life and posit that early humans may have preferred to hunt smaller prey, such as primates or rodents, to megafauna.

“Climate change and the human activities that caused the extinctions we’ve documented are now accelerating at unprecedented rates.”

The researchers also analyzed the role of contemporary climate change trends — including temperature fluctuations and varying monsoon intensity — on the extinction pattern. While changes in climate may have elevated the extinction risk for species that were dependent on annual water sources, such as Hexaprotodon sp., the researchers found that climate change alone does not explain the low-magnitude but strongly size-biased extinction that they documented. The researchers noted that all of the extinct species they identified had survived periods of drought. 

The researchers also note that Asian elephants, tigers, and other large mammals in India had extensive ranges extending from Turkey to Southeast Asia, which improved their chances of survival. The extinct species’ ranges, however, were limited to the Indian Subcontinent, the researchers explain. They note that some species, including the Asian elephant, are known to inhabit refugia — areas that offer protection during drought and other periods when conditions become unfavorable.  

The fact that India’s large mammals have proven resilient to the presence of humans is no excuse to become lax about conservation, Jukar cautioned. 

“Today’s mammals are facing many of the same pressures that these extinct mammals faced, but they are confined to smaller and smaller ranges,” he said. “Climate change and the human activities that caused the extinctions we’ve documented are now accelerating at unprecedented rates. If we ignore these factors, we will lose the elephants, rhinos, and tigers that have survived.”

Provided by University of Yale

African Crocodiles Lived In Spain Six Million Years Ago (Paleontology)

Millions of years ago, several species of crocodiles of different genera and characteristics inhabited Europe and sometimes even coexisted. But among all these species, it was thought unlikely that crocodiles of the genus Crocodylus, of African origin, had ever lived in the Mediterranean basin. The remains found in the Italian regions of Gargano, Tuscany and Scontrone over the last few decades confirm that they did.

A crocodile next to a mastodon of the genus Anancus and primitive horses of the genus Hipparion in a similar environment to what could have been Valencia six million years ago. ©José Antonio Peñas (SINC).

Now, a study published in the Journal of Paleontology corroborates this with the fossils of two crocodiles measuring about three metres in length that were discovered in the Valencian Venta del Moro site -excavated by researchers from the University of Valencia between 1995 and 2006-, and which were ascribed at the time to the Crocodylus checchiai species . This new work describes the remains more than 14 years after they were found for the first time.

“Our comparisons indicate that this material clearly does not belong to the Diplocynodon genera -an extinct genus of alligatoroid, similar to today’s caimans- or Tomistoma -similar to gavials-, the only other two crocodilians described so far for the late European Miocene,” as Ángel Hernández Luján, a palaeontologist at the Miquel Crusafont Catalan Institute of Palaeontology (ICP) and co-author of the work, has explained to Sinc.

However, as the remains are too fragmented, an analysis of the cranial bones, isolated teeth and osteoderms (bone plaque on the skin) suggests that they could belong to the C. checchiai species, as assigned at the time of their discovery, but their taxonomy is still not completely clear and hinders a more precise specific identification. In any case, “the morphology of the Venta del Moro crocodile remains is congruent with the Crocodylus genus,” the researcher states.

Swimming from Africa to Europe

The fossil remains of this Valencian site, which are the first Crocodylus in the Iberian Peninsula, “unequivocally” support the non-occasional dispersion of this genus from Africa to Europe during the late Miocene, according to palaeontologists. The discovery of two partial individuals, instead of just one, could indicate that a whole population was present in this area.

During their “colonisation”, these reptiles spread more significantly in the southern areas of Mediterranean Europe, as suggested by the Italian and Spanish areas where the fossils have been found. “All European localities with late Miocene crocodilians, including Venta del Moro, were at that time close to the northern Mediterranean coast and therefore easily accessible thanks to specimens that became scattered in the seawater,” the authors stress in the study.

“What is most certain is that it would have also inhabited the coasts of Murcia and Andalusia, although we cannot rule out that it would also have become dispersed along the coast of Catalonia and the Balearic Islands,” Hernández Luján has pointed out to SINC. But how could they have got there from the African coasts?

The researchers’ hypothesis is that these crocodiles swam from one continent to another in the sea before a land connection was established between Africa and Europe. This idea would be supported by the behaviour of modern crocodiles, which are good swimmers and can even reach 32 km/h in the water.

An example of this is the current saltwater crocodile (Crocodylus porosus), which can make significant forays into the open sea to colonise other islands or other continents between Oceania and South-East Asia. “You only have to look at how easily it moves in the open sea to be seen in the waters of the Solomon Islands or even in French Polynesia,” says the palaeontologist.

But there are more examples that reinforce this hypothesis. Because of its anatomical similarity to American crocodiles, the extinct species Crocodylus checchiai, which originated in Libya and Kenya, could well be its ancestor. This suggests that crocodiles were able to cross the Atlantic Ocean during the Miocene, which would explain the appearance of the genus in America.

Therefore, in the case of the specimens found in Venta del Moro, swimming from the African to the European continent “must not have meant a great effort for them before they reached the Peninsula,” the researcher concludes.

References: Delfino, M., Luján, À, Abella, J., Alba, D., Böhme, M., Pérez-Ramos, A., . . . Montoya, P. (2020). Late Miocene remains from Venta del Moro (Iberian Peninsula) provide further insights on the dispersal of crocodiles across the late Miocene Tethys. Journal of Paleontology, 1-9. doi:10.1017/jpa.2020.62

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