A tale of enduring, if misplaced, love between a black female swan and a large pedal boat has sparked another round of animal frenzy in Germany, a country that is still celebrating the antics of Knut the polar bear and mourning the death of a panda.

The swan, known as Black Petra, became fixated with the plastic swan-shaped pedalo when she touched down on a lake, the Aasee, in northern Germany last year.

Dozens of film crews turned up this week to see if the love had survived the winter or whether Black Petra would mate with a real swan. She stuck to the boat, stirring hope among all those Germans brought up to believe that summer romances are doomed.

“I was sure that her boat fixation would be short-lived,” said Dirk Wewers, a behavioural biologist at the nearby Mönster zoo. “But in the meantime it is clear that this is an imprint.”

Konrad Lorenz, the late Austrian-German behavioural thinker, found that freshly hatched birds bonded socially with the first moving object they saw — and called the process “imprinting”.

Black Petra spent last spring and summer swimming alongside the four-seater pedalo and making the usual mating gestures. The couple became a huge tourist attraction, prompting souvenirs and music CDs trumpeting the virtues of mismatched love. When winter came the pedalos were moored as usual in the boat house but Black Petra and her swain were allowed to spend the cold months together in Mönster zoo. Visitors’ figures topped the million mark.

The true test of the odd couple came this week. First Black Petra was put with half a dozen eligible, normal black swans. They attacked her and within days she had turned her back on them and was waddling after her favourite pedal boat.

“The boat remains the most important thing in her life,” said Ilona Zaelke, a zoo spokes-woman. “She feels safe and protected.”

In part, the national fascination with Black Petra, Knut and the panda Yan Yan (a celebrated resident of Berlin zoo that died last week) is to do with human sympathies for rejected animals. Petra plainly cannot have a normal relationship, Yan Yan failed to produce a cub and Knut was left out to die by his mother.

The pathos of Knut became clear yesterday with the launch of the first Knut pop song.

Trilled by a nine-year-old girl called Kitty, the lyrics begin: “Knut is a cuddly bear/ Who doesn’t have a mummy anymore.” In fact Knut’s mother, Tosca, is alive and well. She just does not like children very much.

Germans take the animal world very seriously. Headlines such as “Knut should die” stemmed from a row about one of Europe’s most advanced animal protection laws. Leipzig zoo put a bear cub to sleep because it had been rejected by its mother and it would be illegal to bring it up with human bottle feeding. The law says that animals have to be reared in a manner appropriate to their species.

An animal rights protester took the zoo to court — and said that to be consistent, Knut should also have been killed at birth. That set off a storm of protest — and some hard thinking about animal protection.

Yet there has always been a clash between animal legislation and a world that uses animals as meat and as performers. The first modern animal protection was put into place by the Nazis in 1933.

Just friends

— Mr P, a Gloucestershire peacock, spent last summer presenting his plumage to a considerably less amorous petrol pump

— Gohan, a hamster named after the Japanese word for “meal”, was presented to Tokyo zoo’s rat snake Aochan. They became friends — Gohan takes naps on Aochan’s back

— A Briton, Sharon Tendler, “married” dolphin Cindy in a ceremony in Israel. Ms Tendler wore a white dress and veil, presenting Cindy with a herring

— A one-year-old orphaned hippopotamus and a centenarian giant tortoise became friends at a Kenyan zoo

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