Posts tagged events in natural history
![Przewalski’s Horse - Equus prjevalskii [disputed, generally accepted as Equus ferus przewalskii]
The Przewalski’s horse, or takhi, is the only “true” wild horse remaining in the world, and is distinct from Equus ferus caballus, the domesticated horse. Though Przewalski’s horses and domesticated horses can interbreed and produce fertile offspring, the Przewalski’s horse has an extra pair of chromosomes, distinctive dentition, and a convex profile (“Roman nose”) uncommon in most breeds of domestic horse. The subspecies is believed to have diverged from Equus ferus ferus around 125,000 years ago, but the two groups interbred for at least 25,000 years before true geographical isolation began.
The discovery of the takhi in the Mongolian steppes in 1881 was followed by the collection of entire herds through hunting and rounding up to be kept in zoos. The last wild herd was spotted in 1967, and the last individual was spotted in 1969. The most genetically diverse captive herd (living in Askania-Nova in Ukraine) was slaughtered by former German soldiers in the late 1940s for unknown reasons.
Fortunately for conservation efforts, the very few individuals remaining in the world by 1977, when the species was declared “Extinct in the Wild”, proved to be very healthy, at least in terms of genetic vitality. Careful breeding programs started by the Foundation for the Preservation and Protection of the Przewalski’s Horse (FPPPH) in that same year ensured that the genetic diversity remained as strong as possible, given the tiny population. Twelve to fifteen individuals managed to produce small herds in several zoos and preserves, and the population grew at a steady pace for a decade and a half, before the first individuals were re-introduced to the wild, in 1992. Despite
After that first herd of 16 genetically distinct individuals from several zoos was introduced into the Gobi Desert, and successfully formed a herd with numerous healthy foals, Przewalski’s horse was re-classified from “Extinct in the Wild” to “Critically Endangered”. As of 2008, three stable-and-growing herds exist in the wild, in Mongolia and the prohibited-access zone around Chernobyl, Ukraine (a surprisingly good wildlife preserve!). They’re currently considered “Endangered”, and their population outlook is positive, with genetic diversity programs continuing in both zoos and the wild herds.
Proceedings of the Zoological Society of London. 1902.](http://25.media.tumblr.com/tumblr_m7s21nEjD11qk931ho1_400.jpg)
Przewalski’s Horse - Equus prjevalskii [disputed, generally accepted as Equus ferus przewalskii]
The Przewalski’s horse, or takhi, is the only “true” wild horse remaining in the world, and is distinct from Equus ferus caballus, the domesticated horse. Though Przewalski’s horses and domesticated horses can interbreed and produce fertile offspring, the Przewalski’s horse has an extra pair of chromosomes, distinctive dentition, and a convex profile (“Roman nose”) uncommon in most breeds of domestic horse. The subspecies is believed to have diverged from Equus ferus ferus around 125,000 years ago, but the two groups interbred for at least 25,000 years before true geographical isolation began.
The discovery of the takhi in the Mongolian steppes in 1881 was followed by the collection of entire herds through hunting and rounding up to be kept in zoos. The last wild herd was spotted in 1967, and the last individual was spotted in 1969. The most genetically diverse captive herd (living in Askania-Nova in Ukraine) was slaughtered by former German soldiers in the late 1940s for unknown reasons.
Fortunately for conservation efforts, the very few individuals remaining in the world by 1977, when the species was declared “Extinct in the Wild”, proved to be very healthy, at least in terms of genetic vitality. Careful breeding programs started by the Foundation for the Preservation and Protection of the Przewalski’s Horse (FPPPH) in that same year ensured that the genetic diversity remained as strong as possible, given the tiny population. Twelve to fifteen individuals managed to produce small herds in several zoos and preserves, and the population grew at a steady pace for a decade and a half, before the first individuals were re-introduced to the wild, in 1992. Despite
After that first herd of 16 genetically distinct individuals from several zoos was introduced into the Gobi Desert, and successfully formed a herd with numerous healthy foals, Przewalski’s horse was re-classified from “Extinct in the Wild” to “Critically Endangered”. As of 2008, three stable-and-growing herds exist in the wild, in Mongolia and the prohibited-access zone around Chernobyl, Ukraine (a surprisingly good wildlife preserve!). They’re currently considered “Endangered”, and their population outlook is positive, with genetic diversity programs continuing in both zoos and the wild herds.
Proceedings of the Zoological Society of London. 1902.
Lonesome George, dead at 100.
The Pinta Island subspecies of the Galapagos Tortoise (Chelonoidis nigra abingdoni) is now believed to be extinct.
Lonesome George lived in a large corral on the main island of Galapagos, with several females of the Espanola subspecies. George was much fonder of his fronds and sunshine than the females, though, and despite their genetic similarity (meaning that the eggs would likely be fertile), he did not mate with them.
The tortoise subspecies of the islands were second only to the finch adaptations in inspiring Charles Darwin’s theory of natural selection.
I thought I posted about Lonesome George on Darwin Day, but alas, it appears I did not. I have a few posts on tortoises, including a photo of Harriet, a notable Galapagos tortoise who died in 2006, at age 176, but no George.
As Lonesome George was considered a fairly young adult, in terms of tortoise years, his death was unexpected, and the cause is unknown. A necropsy will take place to determine the cause, and his body will be preserved and kept at the Galapagos National Park visitor center.
Events in Natural History: The Pyrenean Ibex
2000: The last Pyrenean Ibex (Bucardo), named Celia, is found dead near the French border, her skull crushed by a fallen tree. The reason for the extinction of the species is unknown, as their habitat was protected since 1918. Since that time, approximately 40 individuals existed at any given time within the Ordesa National Park. Genetic bottlenecking causing lethal recessive genes to appear is a hypothesis.
2002: Previously collected somatic cells from Celia are fused with the emptied oocytes of Capra hircus. 254 embryos reconstructed. 54 embryos transferred to 12 mountain goat/domestic goat hybrids. Of these, two survive beyond two months gestation.
2003: Both pregnancies spontaneously terminate in January. No live births. First attempt at cloning declared a failure in July.
2008: Additional funding procured from Aragon District government of the Pyrenees. 439 embryos reconstructed. 57 transferred into surrogate females. 7 pregnancies result. One pregnancy persists beyond third month.
2009: Surrogate female gives birth to full-term female Pyrenean Ibex in late January. First species brought back from extinction.
2009: Ibex calf dies seven minutes after birth. First species to become extinct twice.
Buck and doe of Pyrenean Ibex subspecies documented by Richard Lydekker, 1898.
A blog for all biological and medical ephemera, from the age of Abraham through the era of medical quackery and cure-all nostrums. Featuring illustrations, history, and totally useless trivia from the diverse realms of nature and medicine.
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