Tasmanian tiger
photographed at the American Museum of Natural History (AMNH) in NYC.

Contact is Roberto E. Lebron
Senior Director of Communications
American Museum of Natural History
79th Street and Central Park West
New York, NY 10024
212-496-3411
rlebron@amnh.org

The thylacine: we extinguished it

Today marks 79 years of the death of the last known thylacine, Benjamin, at the zoo in Hobart (Tasmania). The thylacine, Tasmanian wolf or Tasmanian tiger is one of the classic examples of extinct animals by humans. Its fame is due to its relatively recent extinction, its strange anatomy and the existence of videos of the last thylacine, which transmits certain uneasiness to know that no longer exists. Do you want to know their characteristics, the causes of their disappearance and their cloning project?

THE THYLACINE, A MARSUPIAL

Despite its many names, the thylacine (Thylacinus cynocephalus*) was not related to wolves or tigers (placental mammals), as it was a marsupial animal. Marsupials are a mammals’ infraorder in which the young is born at a very early stage of development, almost in embryonic state. The best known representatives are kangaroos, koalas, wallabies, possums and bandicoots.

Un dels pocs llops marsupials que es conserven taxidermitzats en el món. Museo nacional de Ciencias Naturales, Madrid. Foto: Mireia Querol
One of the few preserved thylacine taxidermy in the world. Museo Nacional de Ciencias Naturales, Madrid. Photo: Mireia Querol

After a very short gestation, newborn moves to one of the mother‘s nipples where is seized several months. In most marsupials, nipples, -and therefore the newborn- are protected by a pouch. When the brood completes its development, it will release the nipple and leave the pouch to explore the outside. Look in the following video the birth and migration of the embryo of a red kangaroo:

DESCRIPTION

The thylacine was native of Australia and Papua New Guinea, but in the seventeenth century (arrival of European settlers Oceania) was found only in Tasmania.

mapa tilacino, thylacine distribution, tigre de tasmania, lobo de tasmania
Old thylacine distribution. Map by Discover Life

It was an animal with physical traits of wolf, tiger and kangaroo due to convergent evolution, which made him a unique case and an enigma to science before their taxonomy was known. Its closest relative is the Tasmanian devil (Sarcophilus harrisii).

He looked like a big dog with a thick, stiff tail. Its weight was about 30 kg on average. The fur was short, gray-brown with 13-20 vertical black stripes at the rear. It is estimated that lived between 5 and 7 years in the wild.

Instal·lació d'exemplars dissecats. Foto: South Australian Museum
Display of taxidermy thylacines. Photo: South Australian Museum

It was capable of bipedal jumps and upright posture for short periods of time. They were also good swimmers. The anatomy of the thylacine when stood up, with its tail resting on the ground, reminds the kangaroo as evidenced by the following filming of 1933:

FEEDING

The thylacine was exclusively carnivorous, feeding on kangaroos, emus, wallabies and wombats. It was a solitary and crepuscular hunter who caught their prey by ambushes, as it was not very fast. It could turn the palm of the leg up like cats do. This increased movement of the leg would have allowed them subdue prey more easily after a surprise attack. In contrast, animals with reduced mobility in the leg, as some canines, prefer the persecution of the ambush and often hunt in herds.

Benjamin abriendo la boca en una respuesta a una amenza similar a un bostezo. Zoo de Beaumaris, foto de David Fleay.
Benjamin gasping similarly to yawning in response to a threat. Hobart Zoo. Photo by David Fleay.

Another unique feature was the ability it had to open its mouth. Equipped with 46 teeth, its powerful jaws could be opened at an angle of 120 degrees, allowing him to swallow large chunks of meat.

La impresionante capacidad bucal del tilacino. Foto: desconocido
The thylacine’s impressive buccal capacity. Photo: video capture by David Fleay

Look in the following video the last moving record of Benjamin (1933), from which was obtained the above screenshot:

To view the 7 videos that remain from this fantastic animal, enter The Thylacine videos.

REPRODUCTION

Thylacines could reproduce from June to December. It were born 2-4 pups per litter, who spent three months in the pouch but were still dependent on its mother‘s milk more than nine months. Unlike many marsupials, in the thylacine pouch opened to the rear of the body.

tilacino embarazada, cria tilacino
Only existing photographs of females with brood in the pouch. Photo taken from The Thylacine Museum

EXTINCTION

Australian Aborigines already knew and hunted the thylacine, as seen in their 1000 b.C art. The first possible thylacine footprints discovered by Europeans are from 1642, although it was not until 1808 that a detailed description of the species was made.

tilacino cazado
Thylacine hunted in 1869. Photo of public domain

There are several hypotheses that point to the extinction of the Tasmanian tiger, in the majority, humans are the main blamable. Like it happens nowadays in Spain, the Tasmanian wolf was quickly accused of killing cattle and hen, so despondent rewards were offered for the animal and was the subject of an intensive hunt. Later research has concluded that its jaw was not strong enough to kill an adult sheep.

Única imatge existen d'un llop marsupial amb una presa. Investigacions recents suggereixen que es tracta d'un muntatge amb un especimen dissecat per donar-li mala fama. Foto de H. Burrell
Only existing picture of a thylacine with a prey. Later research suggest that is a farce with a taxidermy specimen to give them bad reputation. Photo by H. Burrell (1921)

With the colonization of Australia, the habitat and prey of the thylacine were diminished drastically. They were also victims of introduced species on the continent by humans, such as dogs, foxes and dingoes (wolf subspecies). It is also probably that suffered some diseases that lead them to death.

ültimo tilacino salvaje cazado por Wilfred Batty. Foto: desconocido (Wikimedia commons)
Last wild thylacine hunted by Wilfred Batty (1930). Photo: unknown (Wikimedia Commons)

In 1920 the thylacine was already on the verge of extinction. In 1930, it was hunted by a farmer the last known wild specimen and in 1933 arrived at Hobart Zoo the nicknamed Benjamin. In 1936, he was forgotten outside his cage and did not survive the freezing temperatures at night. 59 days before, it had been approved officially the protection of the species.

Only 128 years after his “discovery” the last thylacine died. Photo by David Fleay colored by Neitshade

After the 50 years required by the scientific community without any sightings or evidence of its existence, the thylacine was officially declared extinct by IUCN in 1986. Many claim to have seen the thylacine and even filmed one in the wild, but there are no no definitive evidence.

CURRENT RESEARCH

The International Thylacine Specimen Database is an international database that compiles all existing records of the Tasmanian wolf (museum specimens, bones, photos, videos…). Since 1999, there have been attempts to bring the thylacine back to life by cloning techniques, which have been unsuccessful. In 2008, Australian scientists were able to extract DNA from specimens preserved in alcohol and activate a gene implanting it in a mouse embryo and in 2009 the complete sequencing of mitochondrial DNA was published. The elusive goal is to activate the complete genome of thylacine, to have a real possibility of cloning. But if that happens, what are the ethical, economic and scientific implications of the reappearance of an extinct species? The debate is still open.

*Thylacinus cynocephalus from greek θύλακος (thylakos, “pouch”) and κυνοκἐφαλος (kinokefalos, “dog-headed”).

REFERENCES

MIREIA QUEROL ALL YOU NEED IS BIOLOGY

2 pensaments a “The thylacine: we extinguished it”

Comentaris / Comentarios / Comments:

Fill in your details below or click an icon to log in:

WordPress.com Logo

Esteu comentant fent servir el compte WordPress.com. Log Out / Canvia )

Twitter picture

Esteu comentant fent servir el compte Twitter. Log Out / Canvia )

Facebook photo

Esteu comentant fent servir el compte Facebook. Log Out / Canvia )

Google+ photo

Esteu comentant fent servir el compte Google+. Log Out / Canvia )

Connecting to %s