HISTORY OF ATLANTIC BOTTLENOSE DOLPHINS
Atlantic bottlenose dolphins belong to the family Delphinidae,
genus Tursiops and the species truncatus. Scientists believe
that the first dolphins lived 65 million years ago and that
modern dolphins have existed for 12 million years. Dolphins,
whales and porpoises are Cetaceans (belonging to the order Cetecea).
PHYSICAL DESCRIPTION
Bottlenose dolphins have dark topside and a lighter underside.
The dark coloring causes them to blend in with the water viewed
from above. The light coloring causes them to blend in with the
light rays on the water when viewed from below. This coloration
is a type of camouflage, known as counter-shading helping them
conceal themselves from predators and prey. Dolphins have 80 to
100 conical shaped teeth. Their teeth are used for grasping not
chewing food. Dolphins have a sense of taste, but no sense of
smell. Dolphins are warm-blooded animals. A dolphin’s body
temperature is about 36.5º C (97.7º F). Pectoral flippers,
which dolphins use for steering or guiding themselves while
swimming, contain many bones similar to the structure of a human
hand. Their dorsal fin is used for swimming stability, while
there sleek, streamlined bodies makes them hydro-dynamically
efficient. In utero, dolphins have small amounts of hair on
their rostrums; this hair disappears shortly after birth. Once
they are s, all that remains are the actual hair follicles.
Dolphins have slightly larger brains than humans and a brain size
to body size ratio very similar to our own.
BIRTH AND JUVENILE LIFE
Atlantic bottlenose dolphins are mammals. As with all mammals,
including humans, they have lungs and breath air, are warm-blooded,
give birth to live young and nurse their young.
The gestation period for dolphins is approximately 12-13 months.
Dolphins normally bear one calf per birth, usually born fluke
(tail) first. At birth, dolphins are about 2.5’-3. 5’ long and
weight about 23-35 pounds.
Dolphins reach their maximum size during their early teens, about
10-12 ft. length and between 400-600 pounds. The normal life
expectancy of a dolphin is about 30-40 years.
COMMUNICATION AND INTELLIGENCE
Dolphins, like other mammals, communicate with each other using a variety of
visual and acoustic signals. Body language is an especially important means
of communication between dolphins. Each dolphin has what is known as a
“signature whistle”. Some researchers say that the signature whistles help
dolphins to distinguish between each other. Dolphins do not make noise
through their mouths because their trachea is not connected to the esophagus.
They make noises through their blowholes.
Dolphins also possess a special sensory ability that enables them to navigate
in murky or very deep, dark water where vision is ineffective. Using this
ability, a type of biological sonar called echolocation dolphins can “see”
objects by using their ears. When a dolphin echo-locates, they send out
series of clicks at very fast rates. These sounds, like the dolphin’s
whistles, are produced in small air sacs located inside the dolphin’s nasal
cavity. The echolocation clicks are then focused through the dolphin’s melon,
out into the environment where they bounce off the objects. The returning
echoes reach the dolphin’s inner ear by passing through their lower jawbone.
The echoes construct an image of the object in their brains. The dolphin then
sends out another series of clicks to lean more about their surroundings.
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