Otter fur is known for its softness and density, which helps keep otters warm in cold water. Each otter has about a million hair strands per square inch, making their fur one of the thickest in the animal kingdom. This unique feature allows them to maintain body heat while swimming in chilly environments. The fur is also water-resistant, thanks to natural oils produced by the otters. These oils create a barrier that prevents water from reaching the skin, ensuring that the animal stays dry and insulated. This adaptation is crucial for their survival in aquatic habitats.