Specialists for the first time managed to attach recording cameras to predators and conclude why they are losing weight faster in the last couple of years and more often come to the cities in search of food.
February 2, 2018 in the scientific journal Science published a study on polar bears. Observations have shown that because of the thinning of ice as a result of global warming, animals travel longer distances to seal hunting. This leads to weight loss and worsening of mood in predators, as well as to an increase in the number of attacks on people.
The study was made possible thanks to small cameras, which for the first time managed to be fixed on polar bears. To find out how difficult it was to implement this idea, The Washington Post talked with the American biologist and project manager Anthony Pagano (Anthony Pagano).
Surveillance of nature
In the 1980s, the US Geological Survey began to use tracking devices to monitor the movement of polar bears. Adult individuals were caught, hooked to the neck of the collar and released. The device synchronized with the satellite and transmitted data to one of the stations of scientists – it was convenient, but the researchers still could not know what the predator is doing.
This problem for a long time could not be solved, therefore, until the appearance of good digital cameras about polar bears, little was known. Most of the information about this species was brought by the Canadian researcher and biologist Ian Stirling (Ian Stirling), considered one of the biggest experts on polar bears. From the 1970s to the 1980s, he studied the behavior of animals, observing through a special sight.
The surveillance cameras began to be used massively in the early 2000s. Over time, the devices learned to make small and economical, so that it was easier to fix on a bear. So did the Pagano team.
For the study, only females are suitable. At males the neck is wider, than a head, therefore the collar simply will fall down. In other words, almost all the known information about polar bears is built on surveillance of females.
Usually a group of researchers caught bears from the middle of May to the end of April. They flew by helicopter to the southern part of Alaska and searched for predators in the footsteps or in their popular areas. Pagano notes that it is not an easy task to find a polar bear in a snow-covered area.
When scientists hunt down an animal, they fly up to him in a helicopter and shoot a dart with sleeping pills: exactly the same is used on dogs or cats, just a dose more. After disembarkation, researchers determine the gender and record the characteristic features of the bear, take blood tests and weigh the individual. For this, they use a metal tripod with a chain that raises a predator.
For the first time the Pagano team used a camera collar in 2013: experts bought two devices from a company that made them for deer. As a result, the devices could not stand the cold: the battery was turned off, and the lens on the camera was covered with ice crust. Then the team asked for help from an engineer who manufactured instruments for various kinds of animals. He improved the camera so that it does not turn on if the temperature in the area drops below -17 ° C, so that the battery lasts longer. In addition, the device responded to predator movements and turned on only when the bear was actively moving. This helped extend the battery life up to a year.
From 2014 to 2016, researchers attached 9 collars with cameras to bears. Devices weigh about one and a half kilograms, so the 180-kilogram predator did not feel any inconvenience. When the scientists received the first records, they were delighted. As explained by Pagano, the records helped to understand the behavior patterns of the bears: when they rest, walk, swim, hunt and mate.
The mating of polar bears also remained an unexplored area for a long time. As the scientist explains, usually males “persecute” the female for a long time, until she obeys him. Sometimes female individuals can change the decision before the act, run away or attack the male, but they, though twice as many females, never fight with them.
According to Pagano, it is quite difficult to determine the different characters of bears. Some prefer to hunt for seals, while others prefer an ambush. Some females are more susceptible to “courtship” of males, while others are not. One bear loved to throw pieces of ice into the water: the predator picked up the shard over his head, got up on his hind legs and tossed. “He did it all the time, but it’s not clear why,” concludes Pagano.
A study by Pagano’s team proved that polar bears need far more energy than the rest of the carnivores from the upper chain (lions or black bears). They need to eat every few days to avoid “burning” fat, because they need them during hibernation. In the spring, bears move and hunt calmly, but in the summer, when the ice is rapidly melting, predators have to spend more energy on long voyages.
They recover only in September, when the temperature stabilizes. Thanks to records on which bears, including eat prey, scientists have determined how quickly each individual “burns” energy and why. For a week and a half from wearing a collar with a camera, predators collected 20 kilograms (about 10% of their total weight), but animals that missed most of the production lost the same 20 kilograms.
The prison of polar bears
On the coast of the Hudson Bay in Canada is a small town Churchill, where about 900 people live. Most of the year there reigns a cold and long winter, and in the autumn bears come massively there. Basically, they are looking for food, but sometimes they are attacking people in a stressful state. To stop this, a special prison was built in the city and a special detachment was formed. Its members patrol the territory of the city and when approaching predators they shoot at them with dormant darts.
Sometimes experts have to fly and shoot from a helicopter. When the bear turns off, the team members pull it together into the net, hook it to the helicopter and fly to the base. In the people it is known as a “prison for polar bears”. This is a former hangar for military transport, which was converted into a prison with 28 cameras in 1981. For at least 30 days, bears are given only snow and water to discourage them from wanting to return to the city in search of food. When the time for confinement expires, the helicopter takes them back to the wilderness closer to the water.
Although this conclusion seems too cruel, it works. According to researchers , if in 1987 in settlements in Hudson Bay recorded 1185 bears, in 2011 the figure dropped to 806 individuals.
The migratory route of the bears passes through the town of Churchill for many years, but in the past the attitude towards them was much tougher. In the 1960s, random predators were simply shot at approaches to the city. Now they are trying to scare away from the inhabited territory, and if this does not help, then the bears are locked in a cage.
24 hours a day and seven days a week in the city there is a hotline. If a local resident sees an individual, he calls the specialists and reports the approximate location of the predator. In 2015, the line received 350 calls, of which 77 ended in the capture of a bear. Withered predators looked thin, as the rapid melting of the ice forced them ahead of time to go for the prey. This creates an additional danger, because depleted bears are much more likely to attack people.
In 2016, the number of calls reached 392, but the predators looked more or less thick and did not pay attention to the meat traps set in the city. At the same time, the bears began to notice in other parts of Canada: in the north-west in the village of Taktoyaktuk and in the province of Ontario. In the latter case, the wandering predator was shot.
“Cities of polar bears” are very popular with tourists who want to take pictures of animals. Experts say that sometimes people do not even understand how much they risk their lives. In the migration season, predators become the most aggressive, but some tourists can simply stop the car near the animal and be photographed. Often it ends pitifully – the bear tries to attack the enemies and dies at the hands of policemen or locals who are accustomed to carrying weapons.
In Churchill, the last case of predator attack occurred in 2013. Then two people were injured. As local experts told the edition of Vice, it is likely that the victims ran into a bear at night. In the “city of bears” it is not accepted to walk at night in the dark, because the risk to turn around the corner and meet with the predator increases many times. Those two wounded survived, but the attacking animal was shot.
“My main goal is public safety and human life. We do not like this, but if the bear needs to be killed in order to protect people, we will do it, “said Jeff Chuchmuch, a representative of the special detachment in Churchill.
A white bears specialist with 30 years of experience, Andrew Derocher, hopes that the Churchill predator prevention program will be an example for other territories with a similar problem. But against the backdrop of climate change, he thinks that either animals will be kept in jail or they will be exterminated. “I always thought that the problem of global warming will affect the next generation of biologists, who will deal with it. I did not think that this would happen so quickly, “the expert concludes.