Fascinating photo of a dental examination on a dead hedgehog has won second prize in the DNRF Photo Competition 2019

A photo of a dead hedgehog getting a dental examination is the second place winner in the DNRF Photo Competition 2019. Today, researchers know very little about Danish hedgehogs, but the largest research project on hedgehogs in Denmark to this day seeks to change that. The winning picture was taken by Ph.D. student Sophie Lund Rasmussen, who is also behind the research project, which ultimately attempts to map hedgehogs’ health and challenges.  

The mouth of the hedgehog is wide open, while the animal dentist Hanne Kortegaard, from the University of Copenhagen, investigates the animal’s small, pointy teeth with a metal instrument while wearing blue plastic gloves. This was the motive behind the picture that won second prize in the Danish National Research Foundation’s Photo Competition 2019.

“What we really see in the photo is, unfortunately, a cut off head of a hedgehog that has been run over in traffic. It is a young animal that was losing its milk teeth when it died. Though the situation is sad, we must make the most of it by using the dead animals to learn about the living hedgehogs in nature. Therefore, the animal dentist examines the teeth of the hedgehog to see if there is, for example, periodontal disease, broken teeth or something else, so that we can get an idea of the dental health of Danish hedgehogs,” said Sophie Lund Rasmussen, who took the winning picture with her phone.

Lund Rasmussen is a Ph.D. student at the Department of Biology at the University of Southern Denmark and the natural history museum Naturama in Svendborg. She is the only one in Denmark who is currently researching hedgehogs. In particular, the animal’s health in nature interests her. Before she was given the opportunity to use dead hedgehogs in her research, Lund Rasmussen spent a lot of time looking for living hedgehogs in gardens and in nature at night to, among other things, equip them with radio transmitters.

“It was hard work to follow the hedgehogs in the dark, and because hedgehogs are a protected species, you cannot take samples from the animals without special approval. Even with approval, it is difficult to gather samples from them in the field, because they roll into a tight, spiny ball. So taking samples requires sedation. Therefore, there are many factors that make studies of living hedgehogs difficult,” explained Lund Rasmussen.

The Danes collected hundreds of dead hedgehogs   

The idea to use dead hedgehogs instead of living animals for her research came one evening, when Lund Rasmussen was out driving with her husband and suddenly saw a dead hedgehog that had been run over, on the road.

“I suddenly cried out when I saw the dead animal, which surprised my husband, who thought that we were about to run someone over. When he found out that it was because of the hedgehog, he got annoyed at me and said that I should use the dead hedgehogs for something, instead of just thinking it was sad. And this was actually a really good idea, because why not use the dead animals to understand and help the living hedgehogs,” said Lund Rasmussen.

As part of her Ph.D. project, which is set to be submitted in a few months, she has asked the Danish people to help collect dead hedgehogs from gardens and roadsides and hand them over at one of 26 temporary stands set up around the country.

“The stands were typically set up at stations where people take care of wild animals in need of help or set up at veterinarians, all of whom were nice to help me collect the dead animals and freeze them, so the bodies did not rot. I even persuaded both my mother, my mother-in-law and my Ph.D. supervisors Owen Jones and Thomas Bjørneboe Berg to each set up a stand. I was hoping we would end up with around 300 dead hedgehogs, but we ended up collecting almost 700 specimens, and finally had to close down the collecting sites, because we could not handle any more animals. I was overwhelmed by how much people wanted to help; it was unbelievable!” said Lund Rasmussen.

(Video only available in Danish):

Researchers know very little about hedgehogs in Denmark

Historically, there is very little research on hedgehogs in Denmark, and no one has previously made such an extensive study of the animal, which Lund Rasmussen is currently doing. Dead hedgehogs have been collected from all over the country, and with so many specimens, one can better draw parallels and conclusions in relation to how Danish hedgehogs survive.

“We know virtually nothing about the condition of hedgehogs in Denmark, and it is actually a bit paradoxical when almost all Danes can relate to the animal because it lives so closely with us. Now we have this unique opportunity to examine them, and I am not going to collect this many specimens again, so now we need to do it properly. This study is so extensive that I cannot cover everything in my Ph.D. This project will possibly take many years of research, and I hope to be able to continue my work on the project after the defense of my Ph.D. thesis,” explained Lund Rasmussen

Previously, she had discovered that live hedgehogs often have bad teeth, and therefore, she, together with the animal dentist Hanne Kortegaard, examined the teeth of all the dead hedgehogs. Bad teeth can mean that the hedgehogs have difficulty feeding and therefore become sick, or, in the worst case, die. In Britain, where there is a lot more research and knowledge about the country’s hedgehogs, it has been discovered that the stock has declined dramatically in recent years – perhaps by as much as a third. Lund Rasmussen fears that the situation may be the same in Denmark, and it is important to find out what may be the cause.

Therefore, dental health is also far from the only thing being studied. She has teamed up with a number of Danish specialists in relevant research fields and asked for their expertise to map the health of Danish hedgehogs. A total of about 50 people have been involved in Lund Rasmussen’s project, and everything from the animals’ microbiotas, organs and parasites to the body toxins and the animals’ age has been investigated. Among other things, one of the animals proved to be the world’s oldest known hedgehog with an age of 16 years.

“There is great awareness of the project, because it is the first time that we can say something about the whole population of hedgehogs in Denmark, and because we can argue that the animal will also be a model animal for the condition of other small mammals in Denmark,” said Lund Rasmussen.

Looking forward to collecting the puzzle

Most of the sub-studies are still underway or not yet published, and therefore, Lund Rasmussen cannot reveal much in relation to the results. But she is, among other things, curious to see whether hedgehogs may prove to be carriers of salmonella, something that there have been signs of. If so, we need to start focusing on the fact that hedgehogs may also cause salmonella outbreaks among humans and farm animals. Another part of the project that Lund Rasmussen looks very much forward to seeing the results of is the mapping of the hedgehogs’ genetic information, which will mean a lot for the overall picture of the animals’ health.

““We can use the animals’ genetic information for a lot of different purposes. We can see if the animals are inbred because they may be challenged to find habitats due to roads and intensified farming, which is among the suspected possible causes for the decline of the stock in England. We can also use DNA from their feces to determine what they have eaten, and compare it to how old the individual was, how healthy the animal was at the time of death, and whether it had bad teeth. And this is just some of the possibilities with the genetic information. In this way, we can combine all the different parts of the project together,” explained Lund Rasmussen. She continued:

“I really look forward to gathering all the threads from my research, and in the end conclude how the hedgehogs are doing in Denmark, the challenges the animals have, and what we can do to best help them in the future.”

Read about the first place winner in this year’s competition here

Read about the third place winner in this year’s competition here

Further reading about this year’s competition can be found here

See the winners of last year’s competition here