Skull malformations in lions: Keeping up the pressure

An international team of researchers led by scientists from the Hebrew University of Jerusalem and the Leibniz Institute for Zoo and Wildlife Research (IZW) Berlin examined the incidence of skull malformations in lions, a problem known to be responsible for causing neurological diseases and increased mortality. Their results suggest that the occurrence is a consequence of a combination of environmental and genetic factors. These findings were published in the scientific journal PLOS ONE.

The scientists studied the morphology of 575 lion skulls in museum collections in North America, Europe, Asia, and Africa and noted the incidence of malformations with respect to the death place of lions -- died in the wild or in captivity. The researchers compared the results with skulls of tigers, a similar-sized obligatory carnivorous predator. Whereas tiger skulls of captive origin had a similar incidence of malformations as those of wild origin, large differences occurred between lion skulls from both sources.

Lions have been kept in captivity for centuries and, although they reproduce well, high rates of stillbirths as well as substantial morbidity and mortality of neonates and young lions are reported. Many of these cases were attributed to bone malformations of the skull, including the narrowing of the foramen magnum, the opening at the rear of the skull through which the spinal cord connects to the brain and which can cause associated neurological diseases.

Foramen magnum of lion (Panthera leo) skulls; right: skull of a healthy lion, left: malformed skull.

A scientific collaboration between scientists from the Hebrew University of Jerusalem, the IZW Berlin, University of Oxford, the Zoological Center Tel Aviv-Ramat Gan, and the Blue Pearl NYC Veterinary Specialists showed that only 0.4 % of lion skulls from the wild had a narrowing of the foramen magnum whereas the constricted opening of the foramen magnum had a forty-fold higher chance to occur in lion skulls from captivity (15.8 %). Lion skulls from captivity were also wider and had a smaller cranial volume. These findings in lions and their absence in tigers suggest the presence of an interaction of the rearing environment and a heritable predisposition of lions to the pathology. "The morphological changes in many of the lion skulls from captivity suggest that some of these lions possibly died because the hind brain and spinal cord were compressed by abnormal and excessive bone formation in their skulls, resulting in severe neurological abnormalities," says Dr Merav Shamir from the Hebrew University of Jerusalem. "It would be interesting to know whether this is a lion-specific phenomenon. Similar investigations in other big cats would be valuable to answer this question," added Dr Nobuyuki Yamaguchi from the University of Oxford.

This anomalous skull morphology has been documented in captive lion skulls dating back as far as the 15^th century, and been the subject of many studies since. "And yet," says Dr Joseph Saragusty from the Leibniz Institute for Zoo and Wildlife Research, " the cause of these morphological changes is still not known. The ongoing loss of captive lions to the disease highlights the need for further investigation with a view to reducing its occurrence."

Hope for tigers lives in Sumatra

In time for the third annual International Tiger Day, recent findings from a camera trap survey in Sumatra, Indonesia have uncovered a burgeoning tiger stronghold on an island that typically makes headlines for its rampant loss of forests and wildlife.

Mr. Tomy Winata, an Indonesian businessman, conservationist and founder of Tambling Wildlife Nature Conservation (TWNC, which is a 450km2 privately managed concession), has carried out critical tiger conservation initiatives in the region since 1996, and recently partnered with Panthera, a global big cat conservation organization, to implement this successful survey.

The study's preliminary camera trap data recently indicated an unexpected density of six tigers per 100km2 in the southern region of TWNC. This estimate is nearly double the highest recorded for the island to date. These findings, including camera trap images of tiger cubs like that above, have identified Tambling, which is part of the globally significant Bukit Barisan Selatan National Park (BBSNP), as a beacon of hope for the last remaining 400-500 wild Sumatran tigers.

Panthera's CEO and tiger scientist, Dr. Alan Rabinowitz, stated, "The extraordinary tiger densities that have been discovered in Tambling are the tangible result of Mr. Tomy Winata's program not just to provide tigers sanctuary, but to protect them. Simply put, the main threat to tigers across their range is from poaching. Poaching is not a disease we can't see or a threat we can't identify. It can be beaten if the will is there to do so. Armed with a zero tolerance policy towards poaching, Mr. Tomy Winata and his team have successfully secured a significant area utilizing effective enforcement. This fact, coupled with good science and monitoring, has had the desired results; tigers are now breeding. Tambling is a model tiger conservation site that is giving the Sumatran subspecies a real chance not just to recover...but to thrive."

Prior to TWNC's efforts, Tambling's tigers were subjected to high levels of poaching and habitat loss. However, Mr. Tomy Winata's use of law enforcement patrols carrying out strict protection efforts, and maintenance of lowland tiger habitat and prey populations, has allowed Tambling to emerge as a key site for tigers in Sumatra and across their range. TWNC's initiatives have also benefited Tambling's local fishing community, which Mr. Tomy Winata has supported by providing villagers with employment opportunities, contributions to the community health clinic and school, student scholarships and more.

Mr. Tomy Winata stated, "I am doing all this because it is my belief that nature has provided us with everything we need to survive and live in this world, and yet so many people have taken from her for their own benefit without giving anything back in return. So I hope that my efforts in wildlife conservation and forest and ecosystem sustainability can be a role model for others, so that together we can help save Mother Nature and never forget where we came from."

Situated within a picturesque peninsula forming the southern tip of BBSNP, the TWNC region encompasses a privately managed concession which is critical to the protection and connectivity of core tiger populations in the larger BBSNP landscape -- an area extending 3,568 km2 that represents one of the largest contiguous protected regions of Sumatra.

A wild tiger cub walks past a camera trap in Tambling Wildlife Nature Conservation, Sumatra, 2013.

Panthera's tiger conservation efforts in southern Sumatra began in 2012 with the filming of the BBC Natural World documentary, Tiger Island, which follows Dr. Rabinowitz as he assesses the state of Mr. Tomy Winata's wild tiger conservation initiatives in Tambling.

Today, Panthera's wild cat scientist and post-doctoral fellow, Dr. Robert Pickles, is working with the TWNC team to extend the population density analysis to the northern region of TWNC and implement extensive habitat analyses to determine the vitality of Tambling's ecosystem. Expanding the reach and efficacy of the Tambling tiger conservation project, the field teams will soon implement a new monitoring software known as SMART to track evidence of illegal activities and better evaluate and target law enforcement efforts. Additional activities include assisting local authorities with park boundary delineations and determining additional threats and their solutions, besides poaching, to tigers, their prey, and their habitat.

Through this joint initiative, Panthera is working with Mr. Tomy Winata and TWNC to establish its first 'Tigers Forever Legacy Site.' Dr. Rabinowitz concluded, "There would be no greater legacy than creating safe havens for tigers where the legacy is that they live on, in the wild forever. Together with TWNC, we're one step closer to that becoming a reality."

Sumatran 'tiger map' reveals tiger population higher than expected

Scientists have created the highest resolution map of Sumatran tiger distribution ever produced, revealing that the island now hosts the second largest tiger population on earth. The research, carried out with the Wildlife Conservation Society's Indonesia Program and Forum HarimauKita, will be published in a special issue of Integrative Zoology, on tiger conservation and research methodologies.

Hariyo T. Wibisono and Wulan Pusparini conducted a questionnaire-based survey across the island to identify the status of Sumatran tiger distribution. They found that tigers still occupy a large majority of the remaining available habitat in Sumatra. Of the 144,160 square kilometers (55,660 sq mi) of remaining potential habitat, tigers are present in over 97% (140,226 sq km; 55,141 sq mi). However, only 29% of the habitat found to contain tigers is protected.

"These findings imply that Sumatran tiger population might be much larger than we believed, and could potentially be the second largest tiger population in the world after India," said Wibisono.

The survey also revealed that tigers occupy a great diversity of ecosystems. Tigers were found from 0 meters above sea level in coastal lowland forests, to 3200 meters (10,500 feet) above sea level in high mountain forests and in every eco-region in between.

"There is a need for further scientific population assessment," said Wibisono, "but if the population is indeed as large as this new survey suggests then real actions and more support from tiger experts and the international community should be mobilized in the conservation of Sumatran tigers."

Based on their findings, the scientists recommend that at least five habitats should be reassessed as Tiger Conservation Landscapes (TCLs). A TCL is an area where there is sufficient habitat for at least five tigers and in which tigers have been confirmed to be present in the last 10 years.

Tigers are able to live in a wide range of habitats. A male tiger photographed by a camera trap in montane forest habitat within the Leuser Ecosystem, North Sumatra Province, Sumatra. In this region, tiger signs were discovered at up to 3.200m asl by WCS survey teams.

These habitats include: 1.) Leuser Ecosystem which contains lowland to montane habitat in the northwest, 2.) Berbak-Sembilang containing lowland peat swamps and coastal habitat in southeast, 3.) Ulu Masen Ecosystem containing lowland to montane habitat in northwest, 4.) Batang Gadis containing lowland to lower montane habitat in central Sumatra, and 5.) Giam Siak Kecil in the central part of the island.

Mr. Wibisono sought to undertake this survey because he believed, based on his extensive experience working on the ground in Sumatra, that previous studies underestimated tiger population distribution. He and his colleague's findings verify his hunch and demonstrate that tigers are present at an island-wide scale in Sumatra.

The world tiger population has declined by 50% since 1998, and only an estimated 3,200-3,600 remain in the wild. The presence of tigers over a wide area of habitat in Sumatra is one of the few bright spots in the current state of wild tigers, but more protection is needed to ensure a viable future for this magnificent animal.

"Although tigers are clearly in peril, I am encouraged by the historic commitments made at the recent global tiger summit to increase the number of tigers worldwide," said Zhibin Zhang, editor-in-chief of Integrative Zoology. "At the end of November, the International Tiger Conservation Forum was held in St. Petersburg, Russia. The governments of the 13 tiger range countries agreed to double tiger numbers by 2022."

"By publishing this special issue on tiger conservation and research methodologies we hope to contribute to the efforts by governments, scientists and conservationists to brink tigers back from the brink."

White tiger mystery solved: Coat color produced by single change in pigment gene

White tigers today are only seen in zoos, but they belong in nature, say researchers reporting new evidence about what makes those tigers white. Their spectacular white coats are produced by a single change in a known pigment gene, according to the study, appearing on May 23 in Current Biology, a Cell Press publication.

White tiger at Chimelong Safari Park in China.

"The white tiger represents part of the natural genetic diversity of the tiger that is worth conserving, but is now seen only in captivity," says Shu-Jin Luo of China's Peking University.

Luo, Xiao Xu, Ruiqiang Li, and their colleagues advocate a proper captive management program to maintain a healthy Bengal tiger population including both white and orange tigers. They say it might even be worth considering the reintroduction of white tigers into their wild habitat.

The researchers mapped the genomes of a family of 16 tigers living in Chimelong Safari Park, including both white and orange individuals. They then sequenced the whole genomes of each of the three parents in the family.

Those genetic analyses led them to a pigment gene, called SLC45A2, which had already been associated with light coloration in modern Europeans and in other animals, including horses, chickens, and fish. The variant found in the white tiger primarily inhibits the synthesis of red and yellow pigments but has little to no effect on black, which explains why white tigers still show characteristic dark stripes.

Historical records of white tigers on the Indian subcontinent date back to the 1500s, Luo notes, but the last known free-ranging white tiger was shot in 1958. That many white tigers were hunted as mature adults suggests that they were fit to live in the wild. It's worth considering that tigers' chief prey species, such as deer, are likely colorblind.

Captive white tigers sometimes do show abnormalities, such as crossed eyes, but Luo says any frailties are likely the responsibility of humans, who have inbred the rare tigers in captivity. With the causal gene identified, the researchers ultimately hope to explore the evolutionary forces that have maintained tigers in both orange and white varieties.

Diverse gene pool critical for tigers' survival, say experts

New research by Stanford scholars shows that increasing genetic diversity among the 3,000 or so tigers left on the planet is the key to their survival as a species.

Iconic symbols of power and beauty, wild tigers may roam only in stories someday soon. Their historical range has been reduced by more than 90 percent. But conservation plans that focus only on increasing numbers and preserving distinct subspecies ignore genetic diversity, according to the study. In fact, under that approach, the tiger could vanish entirely.

"Numbers don't tell the entire story," said study co-author Elizabeth Hadly, the Paul S. and Billie Achilles Professor in Environmental Biology at Stanford and senior fellow at the Stanford Woods Institute for the Environment. She is a co-author of the study, which was published April 17 in the Journal of Heredity.

That research shows that the more gene flow there is among tiger populations, the more genetic diversity is maintained and the higher the chances of species survival become. In fact, it might be possible to maintain tiger populations that preserve about 90 percent of genetic diversity.

Rachael Bay, a graduate student in biology at Stanford's Hopkins Marine Station and the lead author of the study, said, "Genetic diversity is the basis for adaptation."

Loss of diversity

The research focused on the Indian subcontinent, home to about 65 percent of the world's wild tigers. The scientists found that as populations become more fragmented and the pools of each tiger subspecies shrink, so does genetic diversity. This loss of diversity can lead to lower reproduction rates, faster spread of disease and more cardiac defects, among other problems.

The researchers used a novel framework, based on a method previously employed to analyze ancient DNA samples, to predict what population size would be necessary to maintain current genetic diversity of tigers into the future. The authors believe this new approach could help in managing populations of other threatened species.

The results showed that for tiger populations to maintain their current genetic diversity 150 years from now, the tiger population would have to expand to about 98,000 individuals if gene flow across species were delayed 25 years. By comparison, the population would need to grow to about 60,000 if gene flow were achieved immediately.

Neither of these numbers is realistic, considering the limited size of protected tiger habitat and availability of prey, among other factors, according to the researchers.

Limited habitat

"Since genetic variability is the raw material for future evolution, our results suggest that without interbreeding subpopulations of tigers, the genetic future for tigers is not viable," said co-author Uma Ramakrishnan, a former Stanford postdoctoral scholar in biology and current researcher at the National Centre for Biological Sciences in Bangalore, India.

Because migration and interbreeding among subspecies appear to be "much more important" for maintaining genetic diversity than increasing population numbers, the researchers recommend focusing conservation efforts on creating ways for tigers to travel longer distances, such as wildlife corridors, and potentially crossbreeding wild and captive tiger subspecies.

"This is very much counter to the ideas that many managers and countries have now - that tigers in zoos are almost useless and that interbreeding tigers from multiple countries is akin to genetic pollution," said Hadly. "In this case, survival of the species matters more than does survival of the exclusive traits of individual populations."

Understanding these factors can help decision-makers better address how development affects populations of tigers and other animals, the study noted.

Conservation efforts for other top predators have shown the importance of considering genetic diversity and connectivity among populations, according to the report. One example is Florida panthers: since individuals from a closely related panther subspecies were introduced to the population, Florida panthers have seen a modest rise in numbers and fewer cases of genetic disorders and poor fitness.

The Eurasian lynx as a key to the conservation and future viability of the endangered Iberian lynx

Understanding the mechanisms which control reproduction in lynx is essential for their continued viability and effective conservation.

A team of international scientists from Europe discovered that the Corpus luteum of the Eurasian lynx (Lynx lynx) has the longest lifespan among mammals known to date. This hormone producing tissue is responsible for restricting this lynx species (and presumably the other lynx species as well) to only having one estrous cycle per year (mono-estrous) and therefore only one opportunity per year to become pregnant. The findings were published in the scientific journal PLOS ONE.

The Eurasian lynx recovered in many parts of its European range.

The scientists from the Leibniz Institute for Zoo and Wildlife Research in Berlin (IZW) took the Eurasian lynx as a "model" species to investigate the reproductive cycle of lynxes in order to assist in the conservation of the highly endangered Iberian lynx (Lynx pardinus), the most threatened cat species worldwide, restricted to a few locations in southern Spain. A key component in the conservation strategy for the Iberian lynx are the captive breeding centers in Spain and Portugal where Iberian lynx are bred in order to be re-introduced back into the wild. Improving reproductive performance in captivity entails a thorough understanding of the mechanisms that facilitate reproduction in these felids.

The team's key discovery is that lynxes have corpora lutea (CLs, the gland producing the pregnancy hormone progesterone) which are maintained in their ovaries over many years -- the longest lifespan known in mammals, and therefore indicative of a reproductive strategy unique for felids -- and probably for mammals in general. In other species, the CLs disappear before, or shortly after, the female gives birth. Surprisingly, the female lynx can switch off its CL's progesterone production when entering a new cycle during spring or before giving birth without destroying the CL. Later on, progesterone is produced continuously, suppressing the follicular development in the ovary and therefore preventing the onset of a second oestrus cycle within the same year. If a female cannot mate during its 5 -- 7 estrous days per year, an entire reproductive period will therefore be lost, reducing fertility and effective lifetime reproductive output, a substantial problem for a small population such as the Iberian lynx.

"To obtain these results, our international team followed the reproductive cycles of captive Eurasian lynx in German zoological gardens and of free-ranging Eurasian lynx in Norway with the help of a Norwegian wildlife research project, Scandlynx, over a period of almost three years. We used advanced three-dimensional ultrasound techniques and in-house hormone analyses to uncover the mysterious development of the oestrus cycle," says veterinarian scientist Johanna Painer from the IZW.

Europe is home to two Lynx species, the Eurasian lynx and the Iberian lynx. Both species experienced drastic declines in population size during the last century. Whereas the Eurasian lynx recovered in many parts of its European range with the help of re-introduction projects, the population of the Iberian lynx crashed completely and was declared to be the most critically endangered felid species worldwide, today.

It is unknown to what extent lynxes will have the flexibility to adapt their reproduction to anthropogenic environmental changes. This study provides essential information for the assisted reproduction techniques in Iberian lynx which continue to be refined and improved, such as artificial insemination or embryo-transfer. Future research will focus on the manipulation of reproductive cycles to increase the reproductive output for breeding centers and to discover the molecular mechanism underlying this unique phenomenon.

TIGER FOUND DEAD

  A tiger was found dead in suspicious circumstance with its limbs missing in the Nllamala Forest in Mabhubhnagar district. Though the big cat reportedly died two days ago, the incident came into light on Thursday when the Shepherds alerted the local officials. It is suspected that the smugglers kills the tiger and cut off its limbs for nails due to the high demands of then\m in the international market. The carcass of the tiger was found at Rushula Cheruvu in the Munnanoor forest range. Rushula Cheruvu is major source of water for the wild animals. That's why the smugglers always keep an eye on this.
              Though the officials also suspected that the tiger was old enough, so it can be possible that the tiger was dead because of its age, and after the death of that big cats, the smugglers came and took away its limbs. The Post-mortem report will ensure the real cause of the death of this tiger.

DOMESTIC CATS CAN BE DANGEROUS TO MANKIND?

        Scientists mapped the genomes of the tigers, lions and snow leopards in a conservation project to save the endangered species. The researches get a huge break through while working on this. they found that the tigers shares 96% of its genomes with the domestic cats. this research also shows that how the white lions get its pale coat and how the snow leopards adapted to the snowy mountain ranges. according to the researchers, cats are very much capable of adoption. they can change their habits when the environment calls for it.
         But a big questions arises now- if 96% of the tiger genomes matched with the domestic house cats then is it possible that these house cats may be very dangerous for us? Since they have many genomes  common with the ultimate predator- The Tigers, it may be possible that that some day these cats attack the human, and if it happens in future it may be a huge trouble to mankind as we all know cats are very common.
         So, we should keep a safe distance from them, for the good of both ends.