The Beringian wolf lived during the last Ice Age in northern Wyoming, the Yukon and Alaska. The wolf was robust, with strong jaws and teeth. The unique adaptation of the skull and dentition of the Beringian wolf allowed it to produce relatively large bite forces, grapple with large struggling prey, and therefore to predate and scavenge on Pleistocene megafauna. The wolf has been comprehensively studied, yielding new information on the prey species and feeding behavior of prehistoric wolves. The Beringian wolf preyed most often on horse and steppe bison, and also on caribou, mammoth, and woodland musk ox. The species survived well into the Holocene before its extinction at the close of the Ice Age, when cold and dry conditions abated and much of its prey also went extinct. The remains of ancient wolves with similar skulls and dentition have been found in north-east Siberia.
Psychoactive drugs, such as caffeine, amphetamine, mescaline, strychnine, LSD, benzedrine, marijuana, chloral hydrate, theophylline, IBMX and others, have a strong effect on animals. At small concentrations, they reduce the feeding rate of insects and molluscs, and at higher doses kill them. Spiders build more disordered webs after consuming most drugs than before. It is believed that some plants developed caffeine in their leaves as a natural protection against insects.
Drugs affect spider's ability to build a web (Credit: NASA)
Spiders
In 1948, German pharmocologist P. N. Witt started his research on the effect of drugs on spiders. The initial motivation for the study was a request from his colleague, zoologist H. M. Peters, to shift the time when garden spiders build their webs from 2am-5am, which apparently annoyed Peters, to earlier hours. Witt tested spiders with a range of psychoactive drugs, including amphetamine, mescaline, strychnine, LSD and caffeine, and found that the drugs affect the size and shape of the web rather than the time when it is built. At small doses of caffeine (10 µg/spider), the webs were smaller; the radii were uneven, but the regularity of the circles was unaffected. At higher doses (100 µg/spider), the shape changed more, and the web design became irregular. All the drugs tested reduced web regularity except for small doses (0.1-0.3 µg) of LSD, which resulted in more ordered webs.
The drugs were administered by dissolving them in sugar water, and a drop of solution was touched to the spider's mouth. In some later studies, spiders were fed with drugged flies. For qualitative studies, a well-defined volume of solution was administered through a fine syringe. The webs were photographed for the same spider before and after drugging.
Witt's research was discontinued, but it became reinvigorated in 1984 after a paper by Nathanson in the journal Science, which is discussed below. In 1995, a NASA research group repeated Witt's experiments on the effect of caffeine, benzedrine, marijuana and chloral hydrate on European garden spiders. NASA's results were qualitatively similar to those of Witt, but the novelty was that the pattern of the spider web was quantitatively analyzed with modern statistical tools, and proposed as a sensitive method of drug detection.
Other arthropods and molluscs
In 1984, Nathanson reported an effect of methylxanthines on larvae of the tobacco hornworm. He administered solutions of finely powdered tea leaves or coffee beans to the larvae and observed, at concentrations between 0.3 and 10% for coffee and 0.1 to 3% for tea, inhibition of feeding, associated with hyperactivity and tremor. At higher concentrations, larvae were killed within 24 hours. He repeated the experiments with purified caffeine and concluded that the drug was responsible for the effect, and the concentration differences between coffee beans and tea leaves originated from 2-3 times higher caffeine content in the latter. Similar action was observed for IBMX on mosquito larvae, mealworm larvae, butterfly larvae and milkweed bug nymphs, that is, inhibition of feeding and death at higher doses. Flour beetles were unaffected by IBMX up to 3% concentrations, but long-term experiments revealed suppression of reproductive activity.
Further, Nathanson fed tobacco hornworm larvae with leaves sprayed with such psychoactive drugs as caffeine, formamidine pesticide didemethylchlordimeform (DDCDM), IBMX or theophylline. He observed a similar effect, namely inhibition of feeding followed by death. Nathanson concluded that caffeine and related methylxanthines could be natural pesticides developed by plants as protection against worms: Caffeine is found in many plant species, with high levels in seedlings that are still developing foliage, but are lacking mechanical protection; caffeine paralyzes and kills certain insects feeding upon the plant. High caffeine levels have also been found in the soil surrounding coffee bean seedlings. It is therefore understood that caffeine has a natural function, both as a natural pesticide and as an inhibitor of seed germination of other nearby coffee seedlings, thus giving it a better chance of survival.
Coffee borer beetles seem to be unaffected by caffeine, in that their feeding rate did not change when they were given leaves sprayed with caffeine solution. It was concluded that those beetles have adapted to caffeine. This study was further developed by changing the solvent for caffeine. Although aqueous caffeine solutions had indeed no effect on the beetles, oleate emulsions of caffeine did inhibit their feeding, suggesting that even if certain insects have adjusted to some caffeine forms, they can be tricked by changing minor details, such as the drug solvent.
These results and conclusions were confirmed by a similar study on slugs and snails. Cabbage leaves were sprayed with caffeine solutions and fed to Veronicella cubensis slugs and Zonitoides arboreus snails. Cabbage consumption reduced over time, followed by the death of the molluscs. Inhibition of feeding by caffeine was also observed for caterpillars.
This is a short list of recently extinct mammals, their dates of extinction, and some more interesting details. Many of these animals were extinct as a result of human hunting or through the destruction of their natural environment.
Javan Tiger (ext. 1990) The photograph of a live Javan tiger taken in 1938
The Javan tiger (Panthera tigris sondaica) was a subspeices of tiger limited to the Indonesian island of Java. As a result of hunting and habitat destruction, this subspecies was made extinct in the 1980s, but the extinction became increasingly probable from the 1950s onwards, when fewer than 25 tigers remained in the wild.
In 2008, an unidentified body of a female mountain hiker was found in Central Java, allegedly died from tiger attack. Villagers who found the body also claimed some tiger sightings in the vicinity. But until concrete evidence can be produced, the Javan tiger must be considered yet another tiger subspecies which is probably extinct.
Zanzibar Leopard (ext. 1996) Panthera pardus adersi, Zanzibar Museum, Helle V. Goldman and Jon Winther-Hansen
The Zanzibar Leopard (Panthera pardus adersi) is an extinct subspecies of leopard endemic to Unguja Island in the Zanzibar archipelago, Tanzania. Efforts to develop a conservation programme in the mid-1990s were stopped when researchers concluded that there was little prospect for the animal's long-term survival.
Rural Zanzibaris’ descriptions of the leopard are coloured by the belief that these carnivores are kept by witches and sent by them to harm or otherwise harass villagers. After the Zanzibar Revolution, a combined anti-witchcraft and leopard-killing campaign was launched under the leadership of the famous witch-finder, Kitanzi. The result of this campaign was to bring leopards to the brink of extinction.
Pyrenean Ibex (ext. January, 2000) Pyrenean Ibex; Image from Cabrera, A. (1914)
The Pyrenean Ibex (Capra pyrenaica pyrenaica) once ranged across the Pyrenees in Spain and France and the surrounding area, including Navarre, the Basque Country, north Aragon and north Catalonia. The last natural Pyrenean Ibex, was found dead on January 6, 2000, killed by a falling tree.
The biotechnology company Advanced Cell Technology, Inc. used nuclear transfer cloning technology to clone the Pyrenean ibex from the tissue that was taken in 1999. The first attempts to clone the species failed. In 2009, one clone was born alive, but died seven minutes later, due to physical defects in the lungs.
West African Black Rhinoceros (ext. July, 2006) Black Rhinoceros in Ngorongoro Conservation Area, Tanzania; photo: Yoky
West African Black Rhinoceros (Diceros bicornis longipes) was once widespread in the savanna of central-west Africa but on 7 July 2006, it was (tentatively) declared extinct.
Around 1980 the population was in the hundreds. The illegal poaching contributed to the species' demise, by 2000 only an estimated 10 survived. An intensive survey of the last remaining habitat of the species in early 2006 found none. There are eight western black rhinoceros alive: six are in the Czech republic and two are in the San Diego Zoo's Wild Animal park. It might be possible to save this species with work between these two locations. Baiji: Chinese River Dolphin (ext. December, 2006) An illustration of the Baiji; author: Alessio Marrucci
Nicknamed "Goddess of the Yangtze", Baiji is classified by the 2007 IUCN Red List as a possibly extinct species. A late 2006 expedition by scientists from six nations failed to find any Baiji in the Yangtze river.
As China industrialized in recent decades, and used the river for transportation, hydroelectricity, and fishing the Baiji population declined drastically. The last uncontested sighting of a baiji was in 2002. This was the first recorded extinction of a well-studied cetacean species directly attributable to human influence.
The Phanerozoic Eon is the eon in which we live, the one during which abundant animal life has existed. I've just found this amazing video on YouTube, it shows the evolution of fish, amphibians, reptiles, dinosaurs, mammals, and primates, starting more than 500,000,000 years ago, and ending today.
