28.1 Introduction
The dolphin has a number of anatomical and physiological features associated with
aquatic living. He is a marine mammal and evolved from terrestrial mammals in last
50 million years.
Dolphins evolved in:
• Swimming, locomotion and jumping in the water;
• Thermoregulation;
• Orientation in the ocean;
• Adaptation of the deep diving (Berta et al. 2006).
28.1.1 Swimming Adaptation
• Hydrodynamic body (fusiform body shape – Raynolds);
• Maximal propulsion and minimal drag;
• The surface area of marine mammal is 23% less than the terrestrial mammals,
obtained by having no hide limbs and have caudal flukes;
• Dolphins have a smooth teguments and less hair (sometimes born with hair
around bears, less this hair, retains hair follicles);
• Legs diminished absorbed into the body (the ancestor of the dolphins once lived
on land 50 million years ago. For new efficient locomotion, the limbs modified
for propulsion and balance;
• Dolphin is the fastest agile swimmer in the world (Iftimovici 2007).
28.1.2 Thermoregulation (Heat Conservation)
• In the context of aquatic life, the dolphin has a fatty layer of blubber (under the
skin which conserves body centrally while allowing the periphery to
remain cold).
• Dolphins have a large body with small surface (for adaptation including decrease
of surface area and increase in internal volume).
• Dolphins have warm blood, therefore they have to keep the body temperature.
• Dolphins reduce the amount of their blood when they go in contact to areas with
cold water (complex circulation system in intermits is used to conserve and
dissipate heat) (Lockyer 1991).
486
V. S^ arbu et al.
The dolphin has a number of anatomical and physiological features associated with
aquatic living. He is a marine mammal and evolved from terrestrial mammals in last
50 million years.
Dolphins evolved in:
• Swimming, locomotion and jumping in the water;
• Thermoregulation;
• Orientation in the ocean;
• Adaptation of the deep diving (Berta et al. 2006).
28.1.1 Swimming Adaptation
• Hydrodynamic body (fusiform body shape – Raynolds);
• Maximal propulsion and minimal drag;
• The surface area of marine mammal is 23% less than the terrestrial mammals,
obtained by having no hide limbs and have caudal flukes;
• Dolphins have a smooth teguments and less hair (sometimes born with hair
around bears, less this hair, retains hair follicles);
• Legs diminished absorbed into the body (the ancestor of the dolphins once lived
on land 50 million years ago. For new efficient locomotion, the limbs modified
for propulsion and balance;
• Dolphin is the fastest agile swimmer in the world (Iftimovici 2007).
28.1.2 Thermoregulation (Heat Conservation)
• In the context of aquatic life, the dolphin has a fatty layer of blubber (under the
skin which conserves body centrally while allowing the periphery to
remain cold).
• Dolphins have a large body with small surface (for adaptation including decrease
of surface area and increase in internal volume).
• Dolphins have warm blood, therefore they have to keep the body temperature.
• Dolphins reduce the amount of their blood when they go in contact to areas with
cold water (complex circulation system in intermits is used to conserve and
dissipate heat) (Lockyer 1991).
486
V. S^ arbu et al.