Spring is coming, so the plan was to write an article about buzzing bees and swelling buds on trees and shrubs and flowers fluttering and dancing in the breeze.
Nature is waking up, I thought to write. But nature has been awake all winter, according to zoologist and snake expert Beate S. Johansen at the University of Agder Natural History Museum and Botanical Garden.
Even the snakes, which according to encyclopedias should lie dormant from around September to April, have not stayed inside, in hibernation.
They awoke in February, some of them. Dry grass. Dry heather. And there they are, wide awake. Vipers lying in the sun warming their sperm.
Getting ready for mating
He has arrived in good time. The female viper is still dormant in underground passages.
But the male no longer sleeps. It is getting ready.
“The viper’s sperm is maturing,” Johansen says.
‘Maturing’ is the technical term. The male viper must have mature sperm before mating.
“Because of the heat,” the researcher says, “they come out already in February.”
It could also be due to impatience, but the researcher doesn't really know how the male viper thinks.
Warmer on the ground
Many of us were still wearing winter clothes in February, but Johansen points out that it is warmer on the ground.
It can be up to 20 degrees in tufts of grass and ling when the sun is shining. She knows because she measured it with a handheld infrared thermometer. She measured the temperature of the viper too, using the same device. It was 18 degrees in February.
The researcher also measures weather and light conditions, with a handheld light meter. And she inserts a stick into the mouth of as many smooth snakes as she can. She takes DNA samples, and measures height and weight.
She takes DNA samples from vipers too, but the naturalist uses a different method then. She takes samples from snake skins that she finds. Snakes shed their skin twice over the summer.
Smooth snake, the constrictor
It is the smooth snake (Coronella austriaca) that the zoologist looks for when she is out searching for snakes. But snakes tend to stay in the same areas, whether they are smooth snakes, vipers or grass snakes. They are protected animals and illegal to kill.
Areas with bushes and shrubs, holes in the ground, heaths, bogs and stone piles are ideal for snakes. They thrive in locations where they can quickly escape and hide.
Snakes are secretive. Even when they are completely alert, they tend to lie still or slowly crawl, rather soundlessly, hiding beneath ling and shrubs. They are also sedentary. They like to stay 3-400 metres from their wintering dens. If you see a snake, you can be fairly certain that there are several of them in the area.
Searching for smooth snakes is Johansen's favourite pastime. But the researcher notes grass snakes and vipers too, although she does not have time to document all the species of snakes equally thoroughly.
A battalion of smooth snakes
Johansen knows how many smooth snakes there are in Møvik, the old military area in Vågsbygd, 10-15 kilometres outside the centre of Kristiansand.
She knows exactly because she has seen them. She has photographed them, and she has counted them. Everything has been recorded in a small field notebook. Afterwards, the notes are typed into a document on the computer, where it says that 175 smooth snakes have been in Møvik during the past four years.
You could call that a battalion of smooth snakes on the old military area. With that, Møvik holds the Norwegian record for the number of smooth snakes.
The big ones eat the little ones
The area is well suited for snakes. Grass snakes, blindworms and vipers live in the same area, admittedly not close to each other.
“The smooth snake can easily eat smaller vipers and grass snakes, so life is not entirely risk-free out there,” Johansen says.
The zoologist can reveal that a lot is going on among these snakes. One of her students just found the remains of a smooth snake in the stomach of another smooth snake.
The snake researcher has no evidence that the smooth snake engages extensively in cannibalism. It could be by chance that the snake ate one of its own kind, but it could also be due to fighting over a mate or extreme hunger. Normally it eats blindworms, shrews, voles and lizards.
The smooth snake is a constrictor, harmless to humans but deadly to the tiny grass snake, which slowly loses its breath as it is suffocated by the smooth snake.
A larger grass snake can also eat a smaller smooth snake. In general, being small is not safe. It is best to be large in size.
“The bigger snakes have little to fear from other snakes, but a small viper, grass snake or smooth snake can easily be eaten by larger snakes,” says Johansen.
The most secretive snake
The smooth snake lives a hidden existence under rocks and among low vegetation and is considered the most difficult snake species in Europe to study.
More is known about them now. Johansen started a research project on the biology of smooth snakes in 2018. Since then, she has presented several papers on the snake. A selection is listed below.
Now we know, among other things, that the smooth snake robs birds’ nests. It mates many times a year. We know what it eats, and we know how many there are. Johansen has also improved the map that shows the distribution of smooth snakes in Norway.
Both the species map in the Species Map Service database and the Species Observations reporting have improved. She has entered 513 smooth snake observations in the coastal zone from Oslo Fjord to Southern Norway on the species map, in addition to the 175 observations from Møvik.
The male viper has been going back and forth a bit between the heather tussocks outside and its underground passages since February. But in April, both males and females come out, the vipers, grass snakes and smooth snakes. Spring is coming.
Sources and select scientific papers:
- Mating activity documented: In the paper Mating activity and parturition of the smooth snake Coronella austriaca in Norway, the researchers present the first record of smooth snake mating activity in both spring and autumn in Norway.
- The smooth snake as an egg thief: For the first time in the world, photo documentation has been published of a smooth snake climbing a tree and devouring all the eggs in a bird's nest. The article is a collaboration between Beate Strøm Johansen and hobby photographer Øystein Flaatten, who documented the theft with his mobile phone.
- Encyclopedia article: Here you can see Beate Strøm Johansen's entry about the smooth snake in Store norske leksikon (snl.no), Great Norwegian Encyclopedia.