This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American
Life is tough if you're a northern quoll (Dasyurus hallucatus). These rare, cat-sized Australian marsupials don't have very long life spans—especially males, which tend to die after their first mating experience when less than a year old. You see, all female quolls go into heat at the same time, and it drives the males a little bit mad. They grab the nearest female and engage in violent, hours-long mating sessions that leave the males so depleted they often just wander away, stop eating and die. Very few males live past their first birthdays.
The females don't have it much better. Only about 30 percent of females make it to motherhood. They frequently die during those marathon sex events, and if they survive they're often too injured to stay safe from predators. If they get to the point of giving birth, they're left to raise their young alone. (Quoll litters are huge—eight or more young at a time—which explains why the species can withstand such a high mortality rate.)
As if all of that weren't bad enough, many populations of northern quolls must also contend with invasive cane toads (Bufo marinus). Quolls are opportunistic predators and will eat any insect, amphibian, bird, fruit or rodent they come across. (They like carrion, too.) That's fine, except cane toads are incredibly toxic. If a quoll eats a cane toad, it's dead. Cane toads have been expanding their territory in Australia for years and many northern quoll populations have suffered as a result. Feral cats that eat the quolls have also been a huge problem, as they are with numerous other species throughout Australia.
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But even as northern quoll populations disappear on the mainland, they remain safe on a few islands off the coast of northwestern Australia. Last week the Western Australia Department of Environment and Conservation announced that a new population of northern quolls has been found on little-explored Molema Island, a rocky outcrop of about 900 hectares in size. Researchers had never surveyed the island before because it's really difficult to explore, but it is part of a proposed new national park, so department officials finally set out to see what was there. They took boats to the island, set up cameras and waited for the results.
They found quolls—and even better, they saw no evidence of cats or cane toads. Scientists also collected droppings so they can try to determine what the quolls are eating and what else lives on the island. They also found droppings and evidence of quoll tracks on two other islands. Principal scientist Keith Morris from the Western Australia Department of Parks and Wildlife told The Australian that islands like these could serve as "little arks" to help protect the quolls from invasive predators and other threats.
Australia has three other species of quolls, but northern quolls are the smallest and most endangered. All quoll species share the same sex-and-death pattern (known scientifically as semelparity), as do several other species on Australia. Most recently a tiny marsupial called the black-tailed antechinus (Antechinus arktos) was discovered in Queensland and New South Wales. It mates for three solid weeks (ouch) and then the male dies. As you might expect, the species is endangered—but not due to its sexual habits. No, its habitat is shrinking, most likely due to climate change.
Photo: Northern quoll by Kieran Palmer via Flickr. Used under Creative Commons license