Polar Bears

Polar Bears live in remote areas that are difficult to study.

This makes monitoring them a challenge, both for single surveys and long-term studies.

For this reason, scientists don't have solid figures on the total number of polar bears worldwide.

They lack data on some populations, specifically those in Russia and East Greenland.

Arctic Russia is especially data deficient.

Not only is it one of the most remote areas on the planet, it lacks basic infrastructure (roads and airfields) and logistical support (small aircraft).

Source:   Polar Bears International