Dolphins Aquatic Adaptations, Dolphin Physiological Characteristics

Dolphinaris gets you a closer look to dolphin’s aquatic adaptations and in general to dolphin’s physiological characteristics. Everything you need to know about dolphins is here in Atlantida Cancun’s Encyclopedia.

Swimming

Swimming speed and duration are closely tied: high speed swimming probably lasts only seconds while low speed swimming may last for long periods of time. Bottlenose dolphins routinely swim at speeds of about 5 to 11 kph. Ergo metric studies indicate burst (maximum) speeds of 29 to 35 kph.

Diving

Bottlenose dolphins generally do not need to dive very deep to catch food. Depending on habitat, most bottlenose dolphins regularly dive to depths of 3 to 45.7 m. Under experimental conditions, the deepest trained dive is 547 m. It is possible for a dive to last eight to ten minutes. Dolphins conserve oxygen while under water. They have a slower heart rate and blood is shunted away from tissues tolerant of low oxygen levels toward the heart, lungs, and brain, where oxygen is needed.

Respiration

This is one of the most surprising dolphin’s aquatic adaptations. A dolphin breathes through a single blowhole on the dorsal surface of its head and holds its breath while below water. During each respiration a dolphin exchanges 80 % or more of its lung air, humans exchange only about 17 % of their lung air with each breath. A bottlenose dolphin's average respiratory rate is about two to three breaths per minute.

Thermoregulation

Bottlenose dolphins deposit most of their body fat into a thick layer of blubber that lies just underneath the skin. This blubber layer insulates the dolphin and streamlines the body. It also functions as an energy reserve. A dolphin's core temperature is about 36.9º C.

In general, bottlenose dolphins have a higher metabolic rate than land mammals of similar size. This increased metabolism generates a great deal of body heat.

Sleep

Dolphins spent about 33 % of each day sleeping. Soviet researchers have shown that deep sleep in bottlenose dolphins may occur in only one brain hemisphere at a time. Research is ongoing.