Press releases

In mammals, males are usually stronger and more competitive than females. Males also show greater inequality in reproductive success – the number of offspring they produce – than females. In spotted hyenas, the opposite is true: reproductive inequality is greater in females than in males. The reason? Female spotted hyenas pass on their social rank and the associated privileges such as priority access to food to their offspring, whereas males do not. These are the findings of a new study on spotted hyenas spanning eight generations across eight clans in the Ngorongoro Crater in Tanzania, carried out by the Ngorongoro Hyena Project of the Leibniz Institute for Zoo and Wildlife Research in Berlin (Leibniz-IZW) and the Institut des Sciences de l’Évolution de Montpellier (ISEM). The study is published in the journal “Science Advances” and may explain why females are the more competitive sex in some species.

On 1 July 2026, wildlife veterinarian Prof Prof h.c. Dr Ursula Siebert took office as Director of the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW). At the same time she was appointed Professor of Interdisciplinary Wildlife Science at the Freie Universität Berlin – a joint appointment of the University and the Leibniz-IZW. Most recently, Siebert headed the Institute for Terrestrial and Aquatic Wildlife Research (ITAW) at the University of Veterinary Medicine Hanover, Foundation.

In popular films and stories, hyenas are usually portrayed simply as hunters and scavengers, but in reality, they actually spend a great deal of time play fighting. A new scientific study dispels preconceptions about these iconic predators and shows that spotted hyenas exhibit highly developed social behaviour and sophisticated communication involving facial expressions and vocalisations. The study is the result of a collaboration between the Department of Ethology at the University of Pisa, the Ngorongoro Hyena Project at the Leibniz Institute for Zoo and Wildlife Research, and Siyafunda Wildlife & Conservation.

For conservation and the management of human-wildlife conflicts, it is of great interest to know which species are eaten by carnivores. Scientists from the Ngorongoro Hyena Project at the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) analysed this for spotted hyenas in the Ngorongoro Crater in Tanzania using DNA analysis of hundreds of faecal samples collected over 24 years. They found that hyenas rarely eat livestock in the multi-use Ngorongoro Conservation Area, which is also used for grazing, and do not regularly prey on black rhinos. The study is published in the journal “Wildlife Biology”. The project has been running for exactly 30 years and studies the spotted hyenas’ social behaviour, health, ecology and interactions with animals and humans.

For several years now, cases of West Nile virus (WNV) infection have been occurring in Germany. The virus circulates between native mosquitoes and birds; human infections occur sporadically. Cases within the Berlin urban area have been reported during the summer months for several years, but until now it was not known which urban areas are conducive to the presence of WNV. Over a two-year period, a research team collected mosquitoes during the summer months from five closely neighbouring but distinct sites in Berlin and tested them for the presence of the virus. They found high infection rates in some of the mosquitoes, but the number of virus detections varied significantly between the sites. Urban planning has a significant influence on the infection rate of mosquitoes, the team concluded in a paper in the journal “Nature Communications”.

Sloths are the slowest mammals on the planet, and living in dense jungles has made them difficult to study. For the first time, scientists have now sequenced and analysed the two-toed sloth genome and revealed the genetics behind their extremely slow metabolism. By mapping their evolution, the international team discovered sloth-specific ‘jumping genes’ that have been conserved over millions of years and are linked to the metabolism. The results, published in the journal BMC Biology, reveal insights into the genetics behind the sloth’s unique biology. This could pave the way for further research into metabolism-related conditions and ageing in other mammals, including humans.

In late May 2026, five Przewalski's horses – one stallion and four mares – from breeding facilities across Europe took their first steps into the wild on the vast plains of the Altyn Dala region in central Kazakhstan. This was a significant milestone for the international reintroduction initiative aimed at returning the species to its ancient habitat. Prior to their release, the horses acclimatised for twelve months at the Wild Equid Reintroduction Center, where they were closely monitored by a team of wildlife veterinarians, biologists and caretakers. Two of the mares have been equipped with satellite collars, which will enable the team to see how well the horses are settling into their new home.

Spotted hyenas live in hierarchically organised groups (clans). An individual’s dominance over another determines priority access to resources such as food or mating partners, and thus reproductive success. However, the rank within the clan can be calculated using different metrics – and that matters. Using data from almost 500 hyenas collected over 28 years, scientists from the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) showed that different metrics best predict the animals’ reproductive success – depending on which reproductive trait they looked at. In the journal “Ecology and Evolution” the scientists argue that the calculation of social rank, and thus also the explanation of hierarchical mechanisms in the world of hyenas and other group-living animals need to be refined.

Bats are the only mammals that can actively fly, enabling many species to perform seasonal migrations. In migratory birds, remaining airborne for many hours is supported by burning fatty acids, something most mammals are uncapable of. Scientists at the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) and Helmholtz Munich have now demonstrated that fatty acid oxidation plays a key role in the metabolism of some bats. By measuring metabolic by-products in the bats’ blood, they found that fatty acid oxidation is particularly important during migration in Nathusius' pipistrelles. The findings have been published in the journal The FASEB Journal.

A team of scientists from Berlin analysed water and sediment samples from six water bodies in Berlin and the adjacent federal states of Brandenburg and Mecklenburg-Western Pomerania, as well as the inflow and outflow of a wastewater treatment plant in Berlin. The scientists analysed bacteria found in these samples and detected a higher diversity and load of antibiotic resistance genes in urban samples. The inflow and effluent from the treatment plant were the most heavily contaminated, but resistant bacteria were also found in rural lakes far from urban areas. The study is published in the journal “iScience”.