Counting Tigers by Their Stripes

Every tiger has a pattern of stripes unique to itself. Computer programs can match photographs of the stripes to a database of known individuals so that researchers can know exactly which tigers are in a particular conservation area. From that information, they can also extrapolate what kind of prey base there is for tigers in that area. Photograph by Michael Nichols/National Geographic Creative.

Counting Tigers by Their Stripes.

Video: Wild Cats of the Forest

Posted by Victoria Hillman in Explorers Journal

Victoria Hillman is a National Geographic Explorer and Research Director for the Transylvanian Wildlife Project overseeing research on carnivores and biodiversity of Europe’s last great wilderness. Follow the expedition here on Explorers Journal through updates from the team.


The Carpathian mountains are home to two species of wild cat, the Eurasian lynx (Lynx lynx) and the European wildcat (Felis silvestris silvestris). In Europe both these species are found in forested areas with low human disturbance and are incredibly elusive with the best method for estimating population numbers and capturing behaviours being the use of camera traps. We have set camera traps up throughout the forest at varying altitudes and differing habitats and have not been disappointed with the results.

The Eurasian lynx is the largest of the four species of lynx found worldwide. Historically, the lynx inhabits mountainous, forested regions from Central Asia and Russia through Europe. The Carpathians are home to the largest continuous population of lynx making it the most important population in Europe since populations in Western Europe have been greatly reduced or completely eradicated due to hunting and habitat loss.

The Carpathian population is not only the second largest (behind Siberia), but is also completely isolated from other populations. Several different literatures describes the population as being a sub-species (Lynx lynx carpathicus), although the exact classification of subspecies is still being debated. In 2000, population estimates ranged from 1,700 to 2,600 — a stark contrast with the most recent estimate for the whole of the Carpathian mountains sitting between 2,300-2,400 individuals. Romania alone is estimated to have approximately 1,200 individuals.

Romania is one of only a few countries within the Carpathians where the lynx is still allowed to be legally hunted. Although populations are considered stable, there are concerns about the future of the Eurasian lynx due to increasing human populations, habitat fragmentation, continued hunting, and inconclusive population estimates. The European lynx is the largest of all the lynx species and is the only one that will regularly prey on ungulates leading to conflicts with hunters resulting in poaching.

We have been encouraged by the footage we have captured so far.  Our work is ongoing to identify individuals and to gain an estimate of the population of the area. Unfortunately, we have received information that our posts and videos are being monitored. We have already had a couple of cameras stolen and do not wish to disclose any further details about the lynx in this area. Here is a compilation of some of the footage we have captured so far.

The wildcat (Felis silvestris), is the most widespread of wildcat species found across Eurasia and Africa. The European wildcat is one of five subspecies of the wildcat and is found across most of Europe. Despite being listed as “Least Concern” on the IUCN Red List, populations are decreasing and have become locally extinct in some countries.

Knowledge on the wildcat in the Carpathians is scarce at best, but it is thought that the population in Romania is around 10,000 individuals.  However, this figure is not based on quantitative data and there is very little research on wildcat populations of the Carpathian Mountains. Although hunting is regulated, there is little effort from officials to protect the cats from poaching or illegal hunting.

This species faces many threats. A major concern is hybridization with domestic or feral cats which can lead to killings via mistaken identity. Other threats include habitat fragmentation and increasing human disturbance.

So far we have identified four individuals, two of which have overlapping territories (possibly a male and a female). The second set of  individuals reside in other areas of the research site. One of the individuals lacks the thick bushy tail, and instead sports a tapered end to the tail associated with the European Wildcat. There is a possibility that this may be a hybrid individual. With more footage coming, it is possible that more individuals will be identified by their markings as well as the locations in which they were seen.

Over the winter months, trips to the site have been less frequent. However, we are still getting some interesting footage on the cameras which is being analyzed during this quieter time. We are busy identifying individuals, territories, movements, and behaviors and we continuously learn more about the wildlife that inhabits our research site. I, for one, am excited to see some of the behaviors that have been caught on camera so far.

NEXTVideo: Brown Bears Fighting, Playing, & Scratching in Transylvanian Woods

A New Species of Wild Cat Found Prowling Brazilian Forests and Grasslands

Posted by Carrie Arnold in Weird & Wild

The tigrina is actually two separate species, say researchers in a new report. Photograph by Tadeu Oliveira
The tigrina is actually two separate species, say researchers in a new report. Photograph by Tadeu Oliveira

Wild cats are charismatic creatures, so you’d think we’d know them all pretty well by now. Just how little we understand—at least in some cases—is reflected in the identification of a new species of cat known as a tigrina in northeastern Brazil.

Scientists have discovered that two populations of tigrina previously thought to be one species do not, in fact, interbreed and thus are distinct, according to results published today in Current Biology.

“So much is still unknown about the natural world, even in groups that are supposed to be well-characterized, such as cats,” says the study’s lead author, Eduardo Eizirik of Pontifícia Universidade Católica do Rio Grande do Sul in Brazil.

“In fact, there are many basic aspects that we still don’t know about wild cats, from their precise geographic distribution and their diets.”

Eizirik’s results have implications for conservation efforts—particularly laws about poaching and the designation of national parkland. Such measures are often focused on individual species.

Recognizing the northeastern tigrina as distinct means that biologists will have to assess its conservation status and determine what steps need to be taken so that both species of tigrina can be adequately protected. (See “Rare Cat Captured in Camera Trap.”)

Ancient Interbreeding

Eizirik and colleagues weren’t looking to discover a new species. Instead, they were looking to understand the evolutionary history of what were thought to be three species of cat from the genus Leopardus:

The Pampas cat (Leopardus colocolo) looks like a large, heavy-set, long-haired house cat. It lives in the grasslands and scrublands of South America, from southern Argentina and Chile up through Peru and Ecuador along the western third of the continent.

Geoffroy’s cat (Leopardus geoffroyiis roughly the same size as the Pampas cat, with a brownish-yellow or gray coat, black spots on its trunk, and dark bands across its tail and limbs. Like the Pampas cat, Geoffroy’s cat likes scrublands and lives throughout Argentina.

The tigrina (Leopardus tigrinus), also known as the oncilla or little spotted cat, lives throughout much of Central and South America. With a yellow-brown coat and black rosettes, the tigrina looks like a house cat-sized leopard. Scientists had previously identified four sub-populations of tigrina, including the southern tigrina, which lives primarily in Brazil’s mountainous forests, and the northeastern tigrina, which lives in savannahs and grasslands. The coat of the northeastern tigrina is slightly lighter, and the rosettes are sightly smaller, than those of its southern relative. (Learn about National Geographic’s big cats initiative.)

Eizirik and colleagues obtained DNA samples from a total of 216 different Leopardus cats across their ranges. Analysis of the DNA sequences found in the mitochondria, the cell’s power plant, revealed ancient interbreeding between the Pampas cat and the northeastern tigrina.

Since an individual only inherits mitochondrial DNA from its mother, researchers could peer into the ancient history of these two felines, and found that they mated together frequently before the two cats split into separate species.

Although the Geoffroy’s cat and the southern tigrina divided into separate species over a million years ago, they began to mate together in the more recent past in the areas of southern Brazil and Bolivia where their habitats overlap. While the two cats interbreed regularly at this contact zone, the mating doesn’t extend to farther areas and the two species remain distinct.

Known Unknowns

When Eizirik and colleagues analyzed the genetics of the two different tigrina populations, however, they were surprised to learn that genes did not appear to be moving between the northeastern and southern tigrinas. (See “Pictures: 7 Cat Species Found in 1 Forest—A Record.”)

“This observation implies that these tigrina populations are not interbreeding, which led us to recognize them as distinct species,” Eizirik says. The researchers have suggested that the northeastern tigrina retain its current name of L. tigrinus, while dubbing the southern tigrina L. guttulus.

“Very little was—and still is—known about this species,” says Eizirik. “There have been some initial studies on its diet, but still most of its basic biology remains poorly known, including density, habitat use, and population trends.”

Follow Carrie Arnold on Twitter and Google+.

Do Animals Get Dementia? How to Help Your Aging Pet

Posted by Liz Langley in Weird & Wild on September 13, 2013

A couple of months ago we told you how the age of certain wild animals is determined. Since then, some of you wondered about age-related changes in those animals.

Now that it’s September, aka World Alzheimer’s MonthAlzheimer’s disease accounts for up to 80 percent of all dementia cases, in which mental abilities decline and impede daily functioning—we asked some experts: Do wild animals and domestic pets suffer from dementia or dementia-like symptoms?

Dempsey, a 14-year-old blonde Labrador retriever. Photograph by Kayana Szymczak, Getty Images
Dempsey, a 14-year-old blonde Labrador retriever. Photograph by Kayana Szymczak, Getty Images

The answer: yes and (probably) no.

Our domestic dogs and cats, who live in safe environments and get veterinary care, can live very long lives—long enough to develop cognitive dysfunction. Little data has been collected on older animals in the wild, but while they may reach old age, if they were to develop dementia-like symptoms, they wouldn’t last very long. (Read “Animal Minds” in National Geographic magazine.)

In a research paper published earlier this year in Ageing Research Reviews, researchers found that in 334 studies, 175 animal species showed evidence of senescence, or the process of growing old.

Dementia Unlikely in Wild Animals

Study co-author Dan Nussey, of the Institute of Evolutionary Biology at the University of Edinburgh, said via email that some of the strongest evidence of and most in-depth studies on senescence come from wild ungulates (such as deer, bighorn sheep, and mountain goats) and seabirds, like the long-lived albatross.

Nussey said that wild animals can show physical deterioration like arthritis or tooth wear, and some cognitive deterioration may occur in the wild, but anything as severe as dementia or Alzheimer’s would simply not allow them to last.

“Wild animals live a tough life,” agreed David Mizejewski, a naturalist with the National Wildlife Federation. “Even early [physical] deteriorations—like age-worn teeth or hips—make it harder for them to survive.” Additional cognitive problems would simply make them too vulnerable to survive.

Domestic Pets Susceptible

On the other hand, domestic pets tend to live in safe environments and receive regular veterinary care. That means many cats and dogs live long enough to develop cognitive dysfunction.

Jennifer Bolser, chief clinician at the Humane Society of Boulder Valley in Colorado, said veterinarians are seeing more cases of cognitive dysfunction syndrome, commonly called canine cognitive dysfunction (CCD). (Related: “OCD Dogs, People Have Similar Brains; Is Your Dog OCD?”)

This is probably because domestic dogs are living longer, thanks to better medical and preventive care starting at a younger age and vets who are more adept at recognizing symptoms.

The most dramatic signs owners might notice are dogs “acting disoriented, walking in circles, or staring into corners or [at] the wall.”

Other symptoms include aggression, changes in sleep patterns, loss of interest in family members, and inability to control urination or defecation “in more than just an incontinent way—almost like they’re forgetting how to be house trained,” Bolser said. Cat owners might also notice their pets yowling at random times of day.

Other illnesses have to be ruled out, though, before cognitive dysfunction is definitively determined.

“Usually it’s a diagnosis by exclusion,” Bolser said. “If everything else is checking out normally,” it probably is cognitive dysfunction.

Amy Johnson, assistant professor of large animal medicine and neurology at the University of Pennsylvania, says she doesn’t know if horses are susceptible too. But she does get calls from owners of elderly horses who report changes in the animals’ behavior and ask if the horse might have Alzheimer’s.

To rule out structural brain changes or brain tumors requires medical tests such as MRIs. Most horse owners don’t want to go to the expense or run the risk of putting their animal under anesthesia, so such questions usually go unanswered.

How Can You Help Your Aging Pet?

Bolser says that although there isn’t a cure, there are ways to manage cognitive dysfunction.

“Keep the [pet’s] brain active, even at an older age,” she said. “Teaching them new tricks, getting them outside, and challenging their brains with new environmental stimuli is very important to helping the brain not deteriorate as quickly.”

Also, adding antioxidants to their diets can help with brain health. A prescription diet fortified with antioxidants, fatty acids, and L-carnitine is available, she said.

There are also some medications, the main one being selegiline, which has been used as an MAO inhibitor antidepressant in people and is also sometimes used for human Alzheimer’s and Parkinson’s patients as well, Bolser said.

Mizejewski has some personal experience with CCD, having lost two dogs to old age. The keys to keeping them alive and healthy, he said, were regular exercise, mental stimulation, social interaction, and a good diet. (See dog pictures submitted to National Geographic.)

“There’s a pity involved when we think about our pets losing cognitive function,” he said. “But on the flip side, I think about if my dogs were wild wolves—they would have succumbed to something else long before they got to this stage of old age and dementia.

“Whether domestic or wild, every animal dies at some point. And at the end of the day, I don’t think one way of life ending is necessarily better than another.”

Credits: Weird & Wild