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DISPLAYING POSTS TAGGED: long-haired rat (2)

Desert rains trigger rat plagues

Author
by Karen Rowe
Publish date
3 August 2011
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Comments (3)

Karen Rowe is a Research Associate at MV where she studies evolutionary ecology and behaviour in birds and mammals.

Record levels of rainfall in the Northern Territory have brought forth one of Australia’s rare and unique native mammals, the Long-haired, or Plague Rat (Rattus villosissimus). These herbivorous rats feed largely on stems and leaves and, with consistently high rainfall, large areas of the desert landscape have become lush with food. Coupled with an unusually high reproductive rate, where a single female can produce more than 200 young in one year, these rats are capable of large-scale population explosions leading to rapid dispersal over huge distances. They have even been documented moving as much as 3 km in a single night.

In the past, these rodents have spread across the arid regions of Australia, including eastern Western Australia, the Northern Territory, eastern Queensland and parts of South Australia. Historic plagues have been documented as far back as 1847, with others occurring in 1916-18, 1930-32, 1940-42, 1948, 1950-52, 1956, and 1966-69.

Once the plague recedes, they vanish almost as quickly as they arrived and during non-plague years, they become rare and hard to find, persisting in only a few locations.

Taking advantage of this unique opportunity to document the latest plague, I joined MV mammal curator, Kevin Rowe, and collections manager, Wayne Longmore, to try to find these rats in the Northern Territory, along the Finke River.

Kevin Rowe and Wayne Longmore MV curator, Kevin Rowe (left), and collections manager, Wayne Longmore (right), trapping rats in the desert rain.
Image: Karen Rowe
Source: Karen Rowe
 

We found them in abundance – nearly all of our live traps contained a long-haired rat, and one had two!

Rattus villosissimus caught along the Finke River Rattus villosissimus caught along the Finke River.
Image: Karen Rowe
Source: Karen Rowe
 

We even found part of the skeleton of one in a bird pellet – the undigested material regurgitated by a bird, particularly in birds of prey.

Bird pellet before dissection Bird pellet before dissection.
Image: Karen Rowe
Source: Karen Rowe
 

Bird pellet after dissection After dissection – most of the skull and jaw were intact (on left).
Image: Karen Rowe
Source: Karen Rowe
 

Long-haired rats build burrows in the sand, consisting of meters of tunnels with multiple entrances and exits. They use these burrows extensively, spending nearly 80% of their time underground.

Rattus villosissimus burrow entrance Rattus villosissimus burrow entrance.
Image: Karen Rowe
Source: Karen Rowe
 

At the Finke River site, the sandy soil made it easy to see footprints into and out of these burrows.

Rattus villosissimus footprints Rattus villosissimus footprints.
Image: Karen Rowe
Source: Karen Rowe
 

Kevin and Wayne are still on the hunt for the plague rat, hoping to find more populations in the Barkly Tablelands and central NT. By studying these rats from throughout the state and recording natural history data such as behaviour and habitat, as well as traits of the rats themselves, including age and reproductive state, we can better understand the ecology and biology of this unique, native, and (most of the time!) rare mammal.

Links:

MV Blog: On rats

On rats

Author
by Craig Robertson
Publish date
26 June 2011
Comments
Comments (1)

Craig is a Melbourne writer with an interest in natural history. He has been a museum volunteer in Birds and Mammals for several years.

Today is the 150th anniversary of the day Alfred Howitt left Melbourne to search for Burke and Wills. By the time the explorers had returned to the Dig Tree in April 1861 there had been no news of them for six months. Public pressure had mounted and the exploration committee responsible sent out Howitt as leader of the Victorian Contingent Party. They would in fact discover the fate of Burke’s party in September that year.

Subsequently Howitt gathered a small but interesting collection of natural history specimens that were delivered to Museum Victoria. Only two mammal species were included: one of two known species of stick-nest rat Leporillus sp. [pictured in a cheeky pose here as a mount by an unknown nineteenth century preparator], and the White-footed Rabbit Rat Conilurus albipes. The Lesser Stick-nest Rat and the White-footed Rabit Rat were once widespread across parts of Australia but have long since been regarded as extinct.

stick-nest rat Leporillus sp Stick-nest rat Leporillus sp. collected by Alfred Howitt.
Image: Craig Robertson
Source: Museum Victoria
 

But there is some good news about rats! The species that the Burke and Wills Expedition knew best was the Long-haired or Plague Rat Rattus villosissimus. The ‘plague’ epithet came not from its carrying any disease, but its tendency to population irruptions reaching plague proportions, as we are currently witnessing with the introduced House Mouse Mus musculus. Burke and Wills travelled through the Channel Country after good rains, similar to the current environment. The rats swarmed over their first camp at Cooper Creek, attacking explorers and their supplies so relentlessly that they were forced to move to the site that subsequently became known for the Dig Tree.

The Long-haired Rat had hardly been sighted since the 1970s, especially during the long drought, and was feared to be heading for extinction. Now there are recent reports that the House Mouse is not the only rodent on the move. Zoologists are delighted that Long-haired Rats are now beeing seen in numbers again in Central Australia, including Alice Springs township. At least one of our native rodents is still out there.

Links:

Australian Dictionary of Biography: Alfred William Howitt (1830-1908)

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