Physiology

The respiratory system of sea otters is very similar to humans and other mammals, but there are some key differences. The main parts of the otter's respiratory system are:

Mouth and nose- used to inhale oxygen and exhale carbon dioxide.

Trachea- carries air to and from lungs.

 Lungs- converts oxygen to carbon dioxide and vice versa; diffusion occurs in the pulmonary alveolus of the lungs. 

• Sea otter's lung capacity is 2.5 times greater than any similar-sized land mammal. They can hold their breathe for up to eight minutes underwater.

• Their high buoyancy comes from the capacity of their lungs and the air they trap between their skin and fur. 

Unlike other marine mammals, sea otters chew their food. They have four incisors to help crush hard food and softened round molars to help chew their food. Their digestive system is similar to most mammals (including humans), it includes:

 Mouth- Produces saliva which helps moisten food and break it down. contains enzymes that help begin the digestion of foods. 

Esophagus- Transports bolus from pharynx to stomach. 

Stomach- Holds ingested food and aids in digestion and absorption. 

Small and large intestine- small intestine absorbs nutrients, large intestines absorption of water from the indigestible residue of food. 

Colon- Reabsorbs fluids and processes waste products from the body and prepare for excretion.

Rectum- collect and hold waste until it’s time to release it; located between small intestines and anus.

• Accessory organs such as the pancreas, liver, and gallbladder play an important role in digestion. 

• Sea otters have a single stomach chamber, which differs from other mammals that usually are double-chambered. The single stomach of sea otters is divided into four sections the esophagus, the fundus, the pylorus, and the small intestine. 

•  Sea otters also have the highest mass‐specific metabolic rates of any carnivore.

• Sea otters walk on four legs because of the way the pelvis connects to the spine. 

• They have 12 ribs and 20-21 vertebrae.

• Very flexible skeleton to allow for contorting and grooming themselves and others. 

• Long, thick tapered tail to help with balance and weight distribution.

•  Short limbs to help paddle in the water. 

•  Skull is flat for better swimming.