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The first attempt at giving foster puppies to she wolves

In May, wolf pups were relocated from the litters of six Nordic zoos. So far the experiment appears to be a success, says Inger Scharis, master's student at Linköping University, who is coordinating the experiment.

Vilande Kolmårdenvarg

This is the first ever attempt to relocate Eurasian wolf pups between litters. No one knew how the she wolves would behave once the foreign puppies had been placed among their own.

“In the U.S. red wolf and coyote pups have been relocated to new litters successfully. That was all we were aware of,” says Inger Scharis.

Today, she stated that the Swedish experiment had gone well…until now.
It remains to be seen how the foster puppies can react to the competition from their new siblings. The experiment’s final report will be completed in September.

Predominately the experiment is ultimately a test to determine whether, in the long run, it is possible to strengthen the Swedish wolf population’s gene pool by relocating puppies bred in captivity to wild she wolves.

The Swedish government commissioned the experiment in early spring at about the same time as the European Commission criticized Sweden for this year's hunting of wolves. Inger Scharis was fortunate enough to sit in on a lecture on zoo biology with Mats Amundin when his phone started ringing persistently. Amundin is a research director at Kolmården and adjunct professor at the Department of Physics, Chemistry and Biology IFM at LiU.

“Sometimes we're just in the right place at the right time. He told us students about the experiment and I immediately asked if he needed help, says Inger Scharis.

Inger Scharis med Kålmårdenvarg

Inger Scharis conducted the relocation experiment as part of an Advanced Biology Project and she is also a coordinator for the Swedish Zoo Association for the entire project. The Swedish Environmental Protection Agency and the Swedish Board of Agriculture is backing the project and Grimsö wildlife researchers are also involved, who are likely to carry out any potential experiments with wild she wolves.

Many questions existed as to how the she wolves would behave. They would of course leave the den when the researchers and staff showed up with the box of pups. Yet how long would it take before the females dared to return? She wolves that have been disturbed, immediately move their pups to a new and more secure den. The question that begged was would they also take the foster puppies with them? Would they really accept the newcomers?

Inger Scharis med varg

During three hectic days in late May, Inger Scharis and Mats Amundin moved the pups.

“May 23 we began at Nordens Ark’s animal sanctuary in West Sweden (Bohuslän) Two puppies, from a litter born five days earlier, were inspected by a vet, weighed, temperature was taken and extra fluid was injected under their skin in order to withstand the long wait until they received milk again,” says Inger Scharis.

The pups were embedded in blankets with hot water bottles and placed in a transportable cage and then driven to Orsa Bear Park. Eight hours later they were relocated to a three-day younger litter and smeared with the biological pup’s urine.

Inger Scharis med varg

“It's easy to get a puppy to pee, just rub its belly like the she wolf would lick the pup’s belly. The idea was that all the puppies would retain similar odours.”

Following this, relocations were conducted between three Norwegian zoos.

“From Kristiansand Zoo and Amusement Park in southern Norway, the staff met us with two four-day old pups. We took them and continued by chartered aeroplane to Namsskogans Familiepark.

Six hours later the puppies were in place with a two-day older foster litter. Two six-day old pups from Namnsskogen would continue to Polar Zoo in the far north, where there was a litter of eight puppies aged eleven days old.

Things got a little nerve-racking, bad weather on the way and a warning about ash deposits from a new volcanic eruption in Iceland.

“But the puppies were on their way up north and the last transport took ten hours. We split up. Mats Amundin immediately proceeded to Järv Zoo in Sweden, which had two litters of puppies of its own to move.”

How did the she wolves react?

“It varied. At the Polar Zoo the game camera noted that the she wolf returned to the den four minutes after the intrusion and a half an hour later, all the pups had been moved. At Järv Zoo it took 15 hours before the she wolf ventured back to the den. Nine seconds later, she had the first puppy in her mouth and fifteen minutes later the entire litter were present in the den,” says Inger Scharis.

Up to that point, it was thought that the she wolves had accepted the foster pups. It took a while until the experiment’s success was established.

In Orsa, it wasn’t until 21 June that staff could identify the new den and confirm that all eight pups were present in the pen. In Namsskogan the den was located between two inaccessible rocks where the pups could not be seen. At the Polar Zoo it was feared that for a long time all the pups were gone. 21 June an area indicating where the wolves might have lain was found. In Järv Zoo one of the females lost one of their own puppies at an early stage.

“Järvzoo litter is perhaps the most interesting because the she wolf's biological pups, were eight days older than foster pups. In terms of the release of pups to wild wolves, the foster pups will more than likely be younger than their new siblings, since wild wolves whelp earlier in the year.”


The Järv Zoo litter (pictured right, photo Inger Scharis) is also the best documented of the litters. They were weighed twice more after being admitted and their development could be compared with their biological siblings who had remained with their mother.

“After twelve days, the foster pups’ weight had increased by 17 per cent, while their biological siblings increased by 58 per cent. The probable reason for this is that the foster she wolf’s own puppies had opened their eyes and become more mobile and in turn more competitive in comparison with the eight-day younger foster pups.”

At the next weigh in the difference in growth had diminished, even though it was obvious that the foster pups were still behind their biological siblings.

It is not an easy task monitoring wolf pups, even in captivity. Following each disturbance the foster she wolf relocates the pups and once they have begun to move around outside the den, at about five weeks old, they are elusive.

“They immediately scatter once they discover our presence,” says Inger Scharis, who patiently sat hour after hour in the enclosure in Järv Zoo and will now travel up north to conduct further studies.

“In general, it is difficult to observe them, even if I’m in the vicinity, it is a disturbance in itself. We need to install a system of surveillance cameras if we are to be able to observe the young wolves' natural behaviour.”
“So far the technology has been the project’s stumbling block. Little bit of a surprise,” says Inger Scharis and laughs, for example the cameras reacted not only to the wolves’ movements but also movements in the foliage and took pictures until the memory card was full.

However it wasn't just luck that determined that Inger Scharis was placed in an unusually exciting master's project, she retains a background that the project could benefit from.

She began studying biology late in life, when she decided it was time for a break from work in film and television production. Project management and coordinating was therefore nothing new to her. Neither film nor canines. For her Bachelor’s project she conducted fieldwork on African wild dogs in Zimbabwe. Back at home in Skärblacka she keeps an entire pack of Australian Cattle Dogs with puppies, perfect for testing the camera.

And oddly, she decided to work at Kolmården when she was five year old.

“I visited Kolmården with my parents when the park had just opened and was totally fascinated. When I was asked what I would do when I grew up, I always replied: ‘Work at Kolmarden’. And now I’m here. “

The future then?

“I would, of course, like nothing better than to follow the study, when pups are released to wild wolves.”

Could it succeed?

“It is too early to draw any conclusions. First the Zoological Society must assess the exchange before it can be recommended.


Curious about TV production? Among other things, Scharis has written the script for the film ‘Oskyldigt dömd’ and wrote sections of the new series for 'Anno 1790', which will premiere on TV this autumn.
She has also written children's books about animals and her writing career began in the mid 80's as a journalist for Norrköping newspapers.

Text and images (from the wolf enclosure in Kolmården):
Gunilla Pravitz


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Last updated: 2011-10-07