For the First Time in the World Body Weight of Wild Brown Bear to be Reliably Determined on Kamchatka

Медвежата на Курильском озере. Фото: Сергей Иванов, участник конкурса РГО "Самая красивая страна"

A unique experiment will be conducted by Russian scientists at Southern Kamchatka Federal Reserve. Here, on the shores of Kurile Lake, a platform scale for measuring the body weight of wild brown bears and an automatic camera that will make it possible to recognize "clubfoot patients" have been installed. Using this combination, it will be possible to determine how the weight of animals changes from the moment of leaving the den until the next hibernation, how much it depends on the number of spawning salmon, the ability to "fish", and the abundance of plant food. No one has ever conducted such research in specially protected natural areas.


“Bears often visit the section of the trail where the scales are now installed. Most of them have been living near ‘Travyanoy’ ranger station for several years now, and we know the animals by sight. A camera trap is placed next to the scales. Thus, having specific figures for the weight of each animal passing through them and data on the weighing time from the shots of the automatic camera, we will be able to correlate this information and finally answer the most frequently asked question by our tourists: ‘How much does this bear weigh?’ Data collected in the spring, after the bears left their dens, and in the fall, when they gained the most fat, will allow us to tell exactly how a bear's weight changes throughout the year,” said the state inspector at  "Kronotsky State Reserve" FSBI Liana Varavskaya.


During the period of abundance of food, when bears are fattening up, they change beyond recognition. Thin animals with dull fur turn into well-fed beauties with thick shiny fur. Lucky fishers gain weight the fastest and most of all.

Government inspectors and scientists have already learned to distinguish between bears that appear every year near the ranger stations or have an unusual appearance. The indicators of changes in the body weight of these animals during the waking period will form the basis of many years of monitoring studies.


Весы на медвежьей тропе. Фото: ФГБУ "Кроноцкий государственный заповедник"

Platform scales are designed for a load of up to one thousand kilograms. They were installed on the trail leading to one of the largest salmon spawning grounds at the mouth of the Khakytsin River. The old decking here will be restored and raised to the level of the measuring device. Bears will be able to walk along their usual route, briefly finding themselves on a 1.5x2-meter platform.

The employees of Kronotsky Reserve pointed out that weighing the bears in the wild without using sedatives will be done for the first time. Moreover, in the past one could only determine the weight of Kamchatka’s largest land predators by weighing the carcasses obtained from hunting areas. According to available data, average weight of an adult male is 350 – 400 kg. At the end of the hyperphagia period it can exceed 600 kg.     

"Despite the widespread information about the body weight of Kamchatka bears, it is often expert approximations. There are very, very few instances of direct weighing of the animals. Now we can expect reliable data on the weight of the bears of southern Kamchatka, where the largest specimens on the peninsula (and some of the largest within the world range) live," said Sergei Kolchin, a researcher at Kronotsky State Reserve and the Institute of Water and Environmental Problems of the Far Eastern Branch of the Russian Academy of Sciences.

One of the largest protected groups of brown bears in the world lives in Southern Kamchatka Federal Wildlife Reserve. It is the largest in Russia. Bears are an important part of the ecosystem of Kurile Lake basin and an indicator of its state, as well as one of the main objects of observation for scientific research and tourists.