20th Century - Artensterben

Tobias caddisfly – museum specimen from the Entomological Collection of ETH Zurich

A museum specimen of the extinct Tobias caddisfly, collected in 1914, in ETH Zurich’s entomological collection. (© Hydropsyche tobiasi – Foto von E. Schmitt, Entomologische Sammlung ETH Zürich, CC BY-SA 4.0, via GBIF)

23. January 2026 Doreen Fräßdorf

Tobias’ caddisfly: Germany’s only endemic species to have gone extinct

Inconspicuous, highly specialised insects Caddisflies are among those insects that hardly anyone notices. They are inconspicuous, quiet and do not impose themselves on people. In 2002, the Austrian entomologist Hans Malicky described them aptly as animals that “cause neither harm nor any particular benefit”, that “do not sting and do

One of the few museum specimens of the extinct Guadeloupe ameiva. (© Laure Pierre, CC BY 4.0, via Wikimedia Commons)

15. January 2026 Doreen Fräßdorf

Guadeloupe ameiva—isolation, colonization & the end of an island species

Islands under pressure The West Indies—including the Lesser Antilles—are among the most species-rich regions in the world. Many lizard and snake species are found exclusively there. These endemic species have adapted over millennia to the conditions of individual islands. Yet this very specialization makes them particularly vulnerable: when habitats are

The kouprey is among the most enigmatic wild cattle in the world. First described scientifically in 1937, it was already extremely rare at that time. Characteristic features include the frayed horn tips of mature bulls and the pronounced dewlap. Today, according to the IUCN, the kouprey is probably extinct. (© Illustration aus Coolidge, H. J. (1940). The Indo-Chinese forest ox or kouprey. Memoirs of the Museum of Comparative Zoology, 54(6), via Biodiversity Heritage Library)

27. June 2025 Doreen Fräßdorf

The Kouprey: A Zoological Mystery

The kouprey is considered one of the most mysterious wild cattle in the world. First described by Western scientists only in 1937, this shy animal from the tropical forests of the tri-border region of Vietnam, Laos, and Cambodia remained scarcely studied for decades. Many zoologists saw the kouprey as a

One of the few photographs of the extinct Schomburgk's deer. The picture was taken in 1911 at the Berlin Zoological Garden. (© Lothar Schlawe, Public domain, via Wikimedia Commons)

9. June 2025 Doreen Fräßdorf

Schomburgk’s deer — Could it still exist?

The riddle of Schomburgk’s deer “No one seems ever to have seen this animal; all that we think we know about it is the existence of its antlers”, noted Phya Jolamark Bhicharana wrote in 1932 about Schomburgk’s deer. The American biologist Francis Harper also wrote in 1945 that this deer—which

The Yemen gazelle, which was described solely on the basis of skins, was probably similar in size to or larger than the mountain gazelle (Gazella gazella), which reaches a body length of up to 1.2 metres. (© The Great Mule of Eupatoria, CC BY-SA 4.0, via Wikimedia Commons)

4. October 2024 Doreen Fräßdorf

Yemen Gazelle

Named after Bilqis, the Queen of Sheba The scientific species name of the Yemen gazelle, bilkis, are derived from Bilqis, the Queen of Sheba, a legendary figure in Islamic, Jewish, and Christian traditions. Her kingdom, renowned for its wealth and cultural flourishing, lay in southern Arabia, in what is now

Ausgestorbene Wandertaube: Jungvogel, Männchen, Weibchen

A depiction of the extinct passenger pigeon created between 1910 and 1914: a young bird (left), a male (middle) and a female (right). (© Louis Agassiz Fuertes, via Wikimedia Commons)

26. September 2024 Doreen Fräßdorf

Passenger Pigeon

From the most common to an extinct bird species When European explorers reached eastern North America in the 16th century, they were amazed at the huge flocks of birds they found in the ancient forests. Compared to Europe, where large parts of the forests had already been cut down, they

Rocky-Mountain-Heuschrecke oder Felsengebirgsschrecke

Illustration from 1902. Rocky Mountain locusts belong to the suborder of short-horned grasshoppers (Caelifera). (© Julius Bien (1826-1909) biography, Public domain, via Wikimedia Commons)

20. September 2024 Doreen Fräßdorf

Rocky Mountain Locust

Record: A swarm of 12.5 trillion locusts The correct biological term for animals that form large groups is “swarm,” but when it comes to large assemblies of migratory locusts, the term “plague” is used because they not only migrate but also devastate entire regions. Migratory locusts differ from ordinary grasshoppers

Mecodema oconnori, verwandter des stephens-island-laufkäfer

Images of the Stephens Island Weevil are rare; the picture shows the ground beetle Mecodema oconnori, which belongs to the same genus. (© S.E. Thorpe, Public domain, via Wikimedia Commons)

9. September 2024 Doreen Fräßdorf

Stephens Island Weevil

From isolated paradise to endangered habitat Stephens Island, a small rocky island in the Cook Strait, is renowned for its unique wildlife. Despite covering only 1.5 square kilometers, the island boasts a remarkable ecosystem that was once home to numerous endemic species, including many land and seabirds. Among its notable

tasmanischer beutelwolf Thylacinus cynocephalus

Male and female thylacine, photographed around 1904 at the Washington, D.C., National Zoo. Between 1850 and 1936, 68 thylacines are documented to have lived in zoos. (© Baker; E.J. Keller., Public domain, via Wikimedia Commons)

1. September 2024 Doreen Fräßdorf

Thylacine

Tasmanian wolf or Tasmanian tiger: Neither wolf nor tiger Dutch seafarer Abel Tasman, who in 1642 was the first European to reach the island of Tasmania, reported “footprints, not unlike the claws of a tiger”. In doing so he had discovered the island’s top predator, which later became known under

Überreste des Beutelwolfs im UCL Grant Museum in London

Remains of the thylacine, which was exterminated by hunting in the early 20th century. (© Doreen Fräßdorf, fotografiert im UCL Grant Museum of Zoology in London, England, 2024)

22. July 2024 Doreen Fräßdorf

Extinctions: How Many Animal Species Have We Already Wiped Out?

There have been five mass extinction events in the history of Earth’s biodiversity, all caused by natural phenomena. It is believed that the sixth mass extinction is currently underway, this time solely driven by human activities. The Thylacine, the aurochs, and the dodo are just a few of the most