Caught on camera: The fossa, Madagascar’s elusive top predator



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Fossa (Cryptoprocta ferox) at the Houston Zoo.
Josh Henderson, CC BY-SA

Asia Murphy, Pennsylvania State University

Mention wildlife on Madagascar and the first thing listeners probably picture is the island’s famed lemurs. As many people know, these unique primates are found nowhere else, and are the most endangered group of mammals in the world. But few people realize that lemurs’ fate is directly bound up with that of Madagascar’s largest predator, the fossa (Cryptoprocta ferox), which is threatened by some of the same pressures.

Fossa are terrier-sized, cat-like relatives of mongoose with tails as long as their bodies. Like other top predators such as lions and wolves, they play a critical ecological role regulating the populations of their prey.

Like much of Madagascar’s wildlife, fossa are found nowhere else in the world. But scientists know little else about them, including how many fossa there are. They are rare, difficult to see in the wild, and lack unique coat patterns that would make it easy to distinguish individual animals.

I worked on a team of researchers from the United States and Madagascar that spent seven years surveying Madagascar’s largest protected area – a zone the size of Connecticut – with trail cameras to see if we could determine how many fossa were there. We found that this area holds a significant portion of the global fossa population, and is likely the last stronghold for this unique species. Our research provides key information that can help correctly assess fossas’ threatened status and lay the basis for appropriate conservation action.

An alert fossa looks out over the rainforest.

Madagascar’s top carnivore

Fossa weigh about 20 pounds and can prey on most of Madagascar’s other species. They are capable hunters on land and in the trees, using their tails for balance and killing by biting through their prey’s skulls. One study found that fossa were largely responsible for two lemur family groups disappearing from forests over a two-year period. Fossa, like other top predators, help keep prey populations at a level that their habitat can support, and rid the population of diseased and weak individuals.

Fossa also exhibit some very interesting behaviors. They are one of nine mammalian species whose sexually immature females go through a period of transient masculinization. During this phase, their clitorises enlarge and grow spines to look like an adult male fossa’s penis. Researchers think this helps sexually immature females avoid the aggressive attentions of males looking for females with which to mate.

In the deciduous forests of western Madagascar, scientists have discovered that male and female fossa will gather together at the same spot year after year to mate. Otherwise, however, fossa were thought to be solitary until 2010, when researchers observed three male fossa working together to kill a lemur. Since then, some male fossa have been seen to team up with another male or two to hunt prey and protect a larger territory than solitary males. And in 2015, our study captured photos suggesting that male fossa in the eastern rainforests will also associate.

Two male fossa captured on camera in northeastern Madagascar.
Asia Murphy

Lack of funding and political instability has made it hard for Madagascar’s government and conservation organizations to study the fossa. Because of their elusive nature, it is particularly hard to figure out basic things, such as how many fossa there are in an area. And without good numbers, scientists can’t assess whether a species is threatened or develop plans for protecting it.

Tracking fossa with cameras

Automatic cameras, known as camera traps, are a standard tool for collecting information on elusive wildlife in remote areas. The only thing “trapped” is the animal’s digital image.

Our images showed what type of habitat fossa used, when they were active, and how they co-existed with other carnivores such as dogs. Variations among individual animals, such as scars, tail width and kinkiness, and the presence and number of ear nicks, made it possible to start picking out certain fossa from the population and “follow” them from one camera to another.

One of our top goals was assessing how many fossa were present in the reserve and how close together they were. Determining density is key for conserving species. Once we knew know how many fossa there were, on average, in a unit of area such as square kilometer, we could estimate how many there were in the entire region and compare between different protected areas.

Flat Tail, seen in 2008 as a young pup (left) and 2013 as a mature male (right). We were able to follow this fossa as he grew up thanks to his strange and unique tail tip.
Asia Murphy & Zach Farris

The value of a number

Over a seven-year period we ran 15 surveys across seven study sites in the reserve. For months on end, we set up cameras, checked them, downloaded data and then moved cameras to survey as much area as possible. In all of this time, I never personally saw a fossa, but two local field assistants saw fossa in the trees once or twice.

Next came three years of analyzing photos, recording which animals had identifying marks and how far those marked fossa moved during their daily activities. Finally, nearly a decade after the very first survey in Masoala-Makira, we had a population estimate.

We calculated the fossa population in Masoala-Makira at 1,061, give or take around 500 animals. This worked out to about 20 fossa per 100 square kilometers. In other words, we had a small town of lemur-eating carnivores living in an area the size of Connecticut.

Why is this important? Because our colleague Brian Gerber did a similar study in southeastern Madagascar, with one important difference: He applied his estimate to the area of all of Madagascar’s protected forests. He estimated there to be 8,626 fossa in the entire world.

Only two protected areas were large enough to hold enough fossa that the population could stay stable, at the very least, despite individuals dying or being killed. We showed that Masoala-Makira is one of them. And as the largest protected area in Madagascar, it will be home to fossa long after they disappear elsewhere due to hunting and habitat loss.

The next priority is to survey Madagascar’s other protected area large enough to hold a self-sustaining population, the Zahamena-Mantadia-Vohidrazana complex, to better estimate the global fossa population. And local governments need to attempt to curb hunting within protected areas and control feral dogs and cats, which can kill native species and spread diseases.

Rare and charismatic species typically get the most conservation attention, especially through events like National Geographic’s Big Cat Week. In fact, however, there are four times more lions than fossa in the entire world. Maybe it’s time for Fossa Friday.The Conversation

Asia Murphy, PhD candidate, Pennsylvania State University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

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Grass trees aren’t a grass (and they’re not trees)



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Xanthorrhoea have no real trunk – just tightly packed leaves.
CC BY-SA

John Patykowski, Deakin University

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Grass trees (genus Xanthorrhoea) look like they were imagined by Dr Seuss. An unmistakable tuft of wiry, grass-like leaves atop a blackened, fire-charred trunk. Of all the wonderfully unique plants in Australia, surely grass trees rank among the most iconic.

The common name grass tree is a misnomer: Xanthorrhoea are not grasses, nor are they trees. Actually, they are distantly related to lilies. Xanthorrhoea translates to “yellow flow”, the genus named in reference to the ample resin produced at the bases of their leaves.

All 28 species of grass tree are native only to Australia. Xanthorrhoea started diversifying around 24-35 million years ago – shortly after the Eocene/Oligocene mass extinctions – so they have had quite some time to adapt to Australian conditions.

Wander through remnant heathland or dry sclerophyll forest, particularly throughout the eastern and south-western regions of Australia, and you’ll likely find a grass tree.


CC BY

Perfectly adapted to their environment

Xanthorrhoea are perfectly adapted to the Australian environment, and in turn, the environment has adapted to Xanthorrhoea. Let’s start the story from when a grass tree begins as a seed.

After germination, Xanthorrhoea seedlings develop roots that pull the growing tip of the plant up to 12cm below the soil surface, protecting the young plant from damage. These roots quickly bond with fungi that help supply water and minerals.

Once the tip of the young plant emerges above ground, it is protected from damage by moist, tightly packed leaf bases, although shoots may develop if it is damaged. The leaves of Xanthorrhoea are tough, but they lack prickles or spines to deter passing herbivores. Instead, they produce toxic chemicals with anaesthetising effects.

All Xanthorrhoea are perennial; some species are estimated to live for over 600 years. Most grow slowly (0.86 cm in height per year), but increase their rate of growth in response to season and rainfall. The most “tree-like” species grow “trunks” up to 6 metres tall, while trunkless species grow from subterranean stems.
Grass trees don’t shed their old leaves. The bases of their leaves are packed tightly around their stem, and are held together by a strong, water-proof resin.
As the old leaves accumulate, they form a thick bushy “skirt” around the trunk. This skirt is excellent habitat for native mammals. It’s also highly flammable. However, in a bushfire, the tightly-packed leaf bases shield the stem from heat, and allow grass trees to survive the passage of fire.

Fire burns the outside leaves but the centre survives.
John Patykowski, Author provided

Xanthorrhoea can recover quickly after a fire thanks to reserves of starch stored in their stem. By examining the size of a grass tree’s skirt, we can estimate when a fire last occurred.

It can take over 20 years before a grass tree produces its first flowers. When they do flower it can be spectacular, producing a spike and scape up to four metres long advertising hundreds of nectar-rich, creamy-white flowers to all manner of fauna. Flowering is not dependent on fire, but it stimulates the process. The ability of grass trees to resprout after fire and quickly produce flowers makes them a vital life-line for fauna living in recently-burnt landscapes.

Grass trees provide food for birds, insects, and mammals, which feast on the nectar, pollen, and seeds. Beetle larvae living within the flower spikes are a delicacy for cockatoos. Invertebrates such as green carpenter bees build nests inside the hollowed out scapes of flowers. Small native mammals become more abundant where grass trees are found, for the dense, unburnt skirt of leaves around the trunk provides shelter and sites for nesting.

Indigenous use of grass trees

For Indigenous people living where grass trees grow, they were (and remain) a resource of great importance.

The resin secreted by the leaf-bases was used as an adhesive to attach tool heads to handles and could be used as a sealant for water containers. This valuable and versatile resin was an important item of trade.

The base of the flowering stem was used as the base of composite spear shafts, and when dried was used to generate fire by hand-drill friction. The flowers themselves could be soaked in water to dissolve the nectar, making a sweet drink that could be fermented to create a lightly alcoholic beverage.

When young, the leaves of subspecies Xanthorrhoea australis arise from an underground stem which is seasonally surrounded by sweet, succulent roots that can be eaten. The soft leaf bases also were eaten, and the seeds were collected and ground into flour. Edible insect larvae residing at the base of grass tree stems could be collected. Honey could be collected from flower stems containing the hives of carpenter bees.

European exploitation

European settlers were quick to clue onto the usefulness of the resin , using it in the production of medicines, as a glue and varnish, and burning it as incense in churches. It was even used as a coating on metal surfaces and telephone poles, and used in the production of wine, soap, perfume and gramophone records.

The versatile resin had been used in everything from medicine to gramophones.
John Patykowski, Author provided

Resin can easily be collected from around the trunk of plants, but early settlers used more destructive methods, removing whole plants on an industrial scale. The resin was exported worldwide; during 1928-29, exported resin was valued at over £25,000 (equivalent to A$2 million today!).

We still have much to learn about grass trees. Current research indicates an extract from one subspecies can be used as a cheap, environmentally-friendly agent to synthesise silver nanoparticles that are useful for their antibacterial properties.

Threats to grass trees

Many of the oldest grass trees have been lost to land clearing, illegal collection, and changes to fire regimes. It’s vital we care for those remaining. Grass trees are particularly sensitive to Phytophthora cinnamomi, a widespread plant pathogen that is difficult to detect and control, and kills plants by restricting movement of water and nutrients through the vascular tissue.

Growing native plants can be a wonderful way to contribute to the conservation of genetic diversity, and attract native fauna into your garden. Grass trees certainly make an interesting conversation plant!




Read more:
It’s hard to spread the idiot fruit


They can easily be grown at home, provided they’re sourced from a reputable supplier. The best way is to grow from seed, but patience is required as growth can be slow. Despite being relatively hardy, grass trees do not like being moved once large or established, so translocation of plants is not advised. In my opinion, the best way to see grass trees in their true splendour is to visit them in their natural habitat.The Conversation

John Patykowski, Plant ecologist, Deakin University

This article is republished from The Conversation under a Creative Commons license. Read the original article.