Polar bears are considered "vulnerable" primarily due to the following reasons:

Polar bears are considered "vulnerable" primarily due to the following reasons:

1. Habitat Loss: Climate change has led to the rapid melting of Arctic sea ice, which is crucial for polar bears as it provides a platform for hunting seals, their primary prey. As the ice disappears, polar bears have to travel longer distances to find food, leading to reduced body condition and lower cub survival rates.

2. Reduced Prey Availability: Declining sea ice affects the availability of seals, which are the main source of food for polar bears. Longer ice-free seasons make it harder for bears to catch enough seals, leading to malnutrition and lower reproduction rates.

3. Pollution: Toxic pollutants like persistent organic pollutants (POPs) accumulate in the Arctic ecosystem and can affect polar bears' health and reproduction. These contaminants enter the food chain and become concentrated in seals, a polar bear's main food source.