Respiration
Otters have a respiration tract that is very similar to those of a human. It has a windpipe, mouth, nose, and lung. The lungs of an otter is about 2.5 times bigger than a similar sized land animal. With that being said they can hold their breath up to 5 minutes. This allows them to dive to deeper depths to be able to find food. The right lung of a sea otter four lobes compared to the right side that only has two lobes. The capacity of air that is in the otters lungs are not only helpful for diving for food, but it also helps them stay afloat.
Digestive System
They have a complete digestive system. Inside their digestive system they have a liver, gall bladder, pancreas, and the gastrointestinal tract. The GI tract has all of the basic digestive organs such as the stomach, intestines, and rectum. Sea otters due lack a cecum, which is the part of the system that helps digest liquids. When they first catch their food, they are able to use tools such as rocks to crack open the shells. Once they have it open they chew their food and it enters their system. The food that they eat goes through their system so quickly that they have to eat about 25% of their body weight. The quick digestive system helps with the absorption of important nutrients and help keep them warm.
Thermoregulation
Otters have a very unique thermoregulation process. In water, the heat conductivity is about 27 times faster than the air. Due to this otters have to have a faster metabolic rate. A sea otters metabolic rate is about 25 times faster than the same size land animal. A sea otter is eating about 25% of their body weight each day to make sure that they are able to keep warm. Sea otters relay on the dense fur and the trapping of air in the fur to keep them warm due to the lack of a blubber layer. They also have a countercurrent heat exchange system which helps take the heat from the blood and keep it in the system rather than out into the environment. The arteries and veins are very close to each other to help keep the heat trapped inside.
References:
Sea otter. Oceana. 2022. https://oceana.org/marine-life/sea-otter/
Adaptations. SeaWorld Parks & Entertainment. https://seaworld.org/animals/all-about/otters/adaptations/