Back From the Brink Biologists Puzzle Over the Return of the Otter

European otters are a mystery to scientists: For decades they were thought to be verging on extinction but now their populations are swelling -- without any help from humans. The swimming predators feel at home in the Alps, where people have mixed feeling about their return.

Andreas Kranz

Alena is asleep, or maybe not. "She can probably hear us," says Susana Freire, pointing to the center of a stack of wood. A tractor chugs past. It is not exactly quiet here, right on the main road, but Freire still doesn't want us to move closer: We might frighten Alena away.

Alena is a European otter and Susana Freire is a biology student at Lisbon University. We are in Niederdorf, in the Austrian Laming Valley, a sleepy but idyllic region. In the north the chalky peak of the Hochschwab mountain forms a backdrop for clichéd tourist snapshots.

Since last spring, the region has also been the focus of a unique research project. The Lutra Lutra, the European otter, has returned to the area -- and no one knows why. Scientists, with Alena's help, now want to get to the bottom of the mystery.

Alena, a female otter weighing in at more than seven kilos, has been providing scientists with clues since May when she wandered into the trap of ecologist Andreas Kranz. Following her capture, vets implanted a transmitter into her abdominal cavity. Ever since, Kranz and his colleagues have been able to track her every move and have been able to answer a number of questions such as: How big is the European Otter's territory in an Alpine region? Where do they prefer to hunt? And, where do the nocturnal predators spend the daylight hours?

At present, Alena prefers to sleep in a pile of cut timber: "The otter is very secure there," Andreas Kranz explains. Despite her proximity to people, and dogs, Alena sleeps between the thick tree trunks hidden from it all. If she does have reason to flee, the Laming river is only two leaps away, and otters are impossible to catch in the water.

Key Evidence

European otters live in hiding. Usually, no one pays attention to them: after all, they are rarely sighted. Experts however have worked out exactly how the creatures reveal their whereabouts: A good kilometer upstream from Niederdorf, Andreas Kranz stops his car and and walks down the embankment to the river. The ecologist points to a rock covered with algae and moss. On the surface there is a strangely bare patch as well as something brown: Otter excrement.

"That is our gold," says Kranz, grinning. The mess includes fish bones, scales and vertebrae. Experts use the remains to work out the diet of the secretive animals. The other stones are left unsoiled and the vegetation is intact. The otter uses specifically placed excrement as a marker: a warning to others to keep out.

But Alena herself isn't particularly welcome either. People living nearby have a mixed reaction to the return of the otters. Many in the valley believe that the animals have been re-introduced as part of a money-saving ploy by an investor who plans to build hydroelectric plants in the region. Local myth has it that the otters will reduce fish stocks, meaning that the investor will have to pay less compensation to leaseholders. It is not true, but it does little to boost Alena's reputation.


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