Quantcast
Animals
vil.sandi / Flickr / CC BY-ND 2.0

Sifaka Lemurs Listed as 'Critically Endangered' Amid Mysterious Die-Off

By Edward Carver

Lemurs in Madagascar have been under pressure from deforestation, poaching, drought and other challenges for years. Now, in the much-visited Berenty Reserve near the island's southern tip, one species faces a mysterious new threat.

In the last month and a half, at least 31 Verreaux's sifakas (Propithecus verreauxi) have died in the reserve. Most were found already dead; others were found gravely ill and later died from respiratory failure. Berenty staff and local scientists have reached out to veterinarians and primatologists across the world. The experts believe that a parasite or tick-borne disease is likely to blame, but the exact cause remains unknown.


This is the one of largest lemur die-offs that scientists in Madagascar can remember. "We haven't seen something like this before," Patricia Wright, a lemur expert and the founder of Centre ValBio, a research center in eastern central Madagascar, told Mongabay.

A Verreaux's sifaka (Propithecus verreauxi)Rhett A. Butler

Verreaux's sifakas were struggling long before this outbreak. The white, fluffy lemurs were already listed as endangered by the International Union for Conservation of Nature (IUCN). The population is highly fragmented and has been declining for decades, according to the IUCN. The species is found in the dry areas and spiny forests of southwest Madagascar.

By coincidence, a large IUCN Red List Primate Specialist Group meeting took place last week in Antananarivo, Madagascar's capital, and reassessing the endangerment status of all lemur species was a top agenda item. The group decided to uplist all nine sifaka species from endangered to critically endangered, according to people in attendance. The status change is not yet official, but during the meeting the Facebook page of the specialist group's Lemur Conservation Network project mentioned it: "We are very sad to announce that all sifaka species are now under the Critically Endangered criteria."

Verreaux's sifakas travel in groups of up to 14 individuals, and at least two of these groups have been killed off in Berenty since late March. Berenty is a private reserve run by a French family that owns a local sisal business. For decades, it has been a research site and a popular ecotourism destination. Lemurs are the main attraction.

Scientists have pieced together clues about the cause of death by assessing the afflicted sifakas that were found still alive. Several of those sifakas had paralyzed hind legs; to move, they had to drag themselves by their hands on the forest floor. (Normally, Verreaux's sifakas have powerful hind legs that allow them to bounce sideways on the ground or jump as far as 3 meters, or 10 feet, from tree to tree.) Within a day, in most of the cases, the paralysis moved up the body and into the lungs, causing death from respiratory failure.

Verreaux's sifakas in a heated territorial chaseRhett A. Butler

Most of the dead sifakas were found covered in ticks, which scientists say may have caused the paralysis by transmitting a neurotoxin or some type of infectious rickettsial bacteria to the sifakas. However, in 2014, scientists found many other Verreaux's sifakas covered in ticks, and they showed no signs of disease.

Another possibility is that the recent deaths were caused by single-cell toxoplasma parasites, which affect the nervous system and which, like rickettsial bacteria, could have been brought to the area by humans. The parasites could have been in the local soil or in cat dung. Tissue and organ samples from the dead sifakas' bodies have been sent to the Institut Pasteur de Madagascar, in Antananarivo, but the test results have not yet come back.

Almost all of the dead sifakas were male, and this at first led scientists to believe that perhaps the deaths were due to aggressive territorial disputes. Because outside threats have forced Verreaux's sifakas and other lemur species to crowd into small areas, this wouldn't be surprising. "When we found the first 9 [dead sifakas] we thought it might be due to an overpopulation," Claire Foulon, the reserve manager, told Mongabay. However, the dead bodies showed no signs of violence, and that theory has now been ruled out. Experts are not sure why most of the dead sifakas are male.

A Verreaux's sifaka nursing her babyRhett A. Butler

Whatever the cause of the illness turns out to be, other types of lemurs do not appear to be as vulnerable to it as the Verreaux's sifakas. So far, none of the many ring-tailed lemurs (Lemur catta) in the same area have been affected. However, one brown lemur (genus Eulemur) was found dead, apparently from the same illness.

No sifakas have been found sick or dead since April 30, so experts are hopeful that the worst may be over. "As most of the news has been pointing to this localized event within a timeline, I am hoping that whatever has caused the 37 deaths (which is the number that was discussed at the IUCN meeting) has ridden its course," Edward Louis, director of the NGO Madagascar Biodiversity Partnership and director of conservation genetics at the U.S.-based Omaha's Henry Doorly Zoo and Aquarium, said in an email to Mongabay. (Louis and other experts cited a death toll in the high thirties, but Foulon, the reserve manager, later told Mongabay that only 31 sifakas had died in the outbreak.)

A team of veterinarians from Germany is now on site to support the Malagasy veterinarian working on the case.

A Verreaux's sifaka dancingRhett A. Butler

Reposted with permission from our media associate Mongabay.

Show Comments ()

EcoWatch Daily Newsletter

Sponsored
Health
"From 1992 to 2016, heat killed 783 workers in the U.S. and seriously injured nearly 70,000, according to a new report on heat risks." InsideClimateNews / USDA

Protect Workers From Extreme Heat, Advocates Urge OSHA

A broad coalition of worker advocacy, public health and environmental groups on Tuesday called on the federal Occupational Safety and Health Administration (OSHA) to create a workplace standard for heat stress.

Keep reading... Show less
Animals
Emilie Chen / Flickr / CC BY-ND 2.0

Against All Odds, Mountain Gorilla Numbers Are on the Rise

By Jason Bittel

The news coming out of East Africa's Virunga Mountains these days would have made the late (and legendary) conservationist Dian Fossey very happy. According to the most recent census, the mountain gorillas introduced to the world in Gorillas in the Mist, Fossey's book and the film about her work, have grown their ranks from 480 animals in 2010 to 604 as of June 2016. Add another couple hundred apes living in scattered habitats to the south, and their population as a whole totals more than 1,000. Believe it or not, this makes the mountain gorilla subspecies the only great apes known to be increasing in number.

Keep reading... Show less
Health
San Cristóbal de las Casas, in the Mexican state of Chiapas. Tjeerd Wiersma from Amsterdam, The Netherlands / CC BY 2.0

How Coca-Cola and Climate Change Created a Public Health Crisis in a Mexican Town

A lack of drinking water and a surplus of Coca-Cola are causing a public health crisis in the Mexican town of San Cristóbal de las Casas, The New York Times reported Saturday.

Some neighborhoods in the town only get running water a few times a week, so residents turn to soda, drinking more than half a gallon a day on average.

Keep reading... Show less
Animals
Plastic trash isn't safe for kids, whether human or bear. Kevin Morgans Wildlife Photography

Even Polar Bear Cubs Can’t Escape Plastic Pollution

By Allison Guy

Plastic bags are often stamped with an all-caps warning: This bag is not a toy. Unfortunately, polar bear moms don't have much control over their kids' playthings.

Keep reading... Show less
Sponsored
Insights
Sea level rise is a natural consequence of the warming of our planet. NASA Goddard Space Flight Center

We Can’t Hide From Global Warming’s Consequences

Over the past few months, heat records have broken worldwide.

In early July, the temperature in Ouargla, Algeria, reached 51.3°C (124.34°F), the highest ever recorded in Africa! Temperatures in the eastern and southwestern U.S. and southeastern Canada have also hit record highs. In Montreal, people sweltered under temperatures of 36.6°C (97.88°F), the highest ever recorded there, as well as record-breaking extreme midnight heat and humidity, an unpleasant experience shared by people in Ottawa. Dozens of people have died from heat-related causes in Quebec alone.

Keep reading... Show less
Health
Stacey_newman / Getty Images

More Than a Third of Schools Tested Have ‘Elevated Levels’ of Lead in Drinking Water

A troubling new report by the U.S. Government Accountability Office (GAO) found that more than a third of the nation's schools that tested their water for lead found "elevated levels" of the neurotoxin. But despite heightened concern in recent years about lead in drinking water, more than 40 percent of schools surveyed conducted no lead testing in 2016.

Keep reading... Show less
Sponsored
Popular
Bill Pugliano / Stringer / Getty Images

Can Elon Musk Fix Flint’s Water?

By Fiona E. McNeill

The Michigan community of Flint has become a byword for lead poisoning. Elon Musk recently entered the fray. He tweeted a promise to pay to fix the water in any house in Flint that had water contamination above acceptable levels set by the U.S. Food and Drug Administration.

Keep reading... Show less
Popular
A researcher at Oregon State University examines creeping bentgrass. Oregon State University / Flickr / Tiffany Woods

You Need to Be Paying Attention to GMO Grass

By Dan Nosowitz

Creeping bentgrass doesn't get as much attention as other genetically modified plants. But this plant tells us an awful lot—emphasis on the "awful"—about how GMO plants are regulated and monitored.

Keep reading... Show less
Sponsored

mail-copy

The best of EcoWatch, right in your inbox. Sign up for our email newsletter!