Dolphins
have outstanding vision in and out of the water. In
the water, their eyes are protected from the sea water
by mucus secreted from glands at the outer corner of
the eye. Their ears, small and hard to detect, are
located just behind the eyes and have no flaps or
lobes. The dolphin's swimming power comes from its
caudal fluke, which moves up and down instead of
side-to-side like fish. The dorsal fin provides
stabilization and may also regulate body heat -- a
dolphin's body heat is very close to human body heat
at 97.7 degrees F (36.5 degrees C)
What
do dolphins eat?
After feeding on mother's milk the first few weeks,
calves begin eating fish at 3 to 4 months and are
weaned at 12 to 18 months. Dolphins feed on all kinds
of fish and crustaceans with adults eating 13 to 14
pounds of fish a day or 20 pounds or more in colder
winter waters.
How
long do dolphins live?
In captivity, dolphins have lived as long as 40 years.
In the wild, though, scientists believe they only live
25 to 30 years.
Dolphin
reproduction
Mature female dolphins will give birth every 2 to 3
years and could give birth as many as eight times
during their lifetimes. They can give birth at any
time of year but most commonly calve in the spring and
summer. Females mature sexually at 8 years of younger
and dolphins are sexually promiscuous with males
competing for females.
How
big are dolphins?
Dolphin calves, usually born in the spring, are 2.5-
to 3-feet long and 25- to 40-pounds. Feeding on its
mother's milk, a calf will double in size in the first
few weeks. Adult males are larger than females. The
Mid-Atlantic dolphins will reach 7 to 10 feet in
length and 300 to 500 pounds by their early teens.
Do
dolphins sleep?
Traveling as much as they do, dolphins must rest some
time. They don't sleep, though. They merely take cat
naps at the ocean's surface for two or three minutes
at a time. At night, those naps increase to seven or
eight minutes.
How
often do dolphins surface?
Because they lack nostrils like most marine mammals,
dolphins surface every 15 to 20 seconds to clear their
blow holes with a burst of air. They commonly dive 200
meters and can remain underwater for 8 to 10 minutes
by slowing their heart beat and controlling their
blood flow. Dolphins only breathe voluntarily rather
than automatically like humans, so if they're knocked
unconscious, they stop breathing.
How
fast do dolphins swim?
Dolphins typically cruise at 5 to 7 miles per hour,
but they have been clocked at 18 to 22 miles per hour
with top speeds of 30 miles per hour.
How
do dolphins travel?
Dolphins travel in pods of up to 15. A pod typically
consists of several adult females, calves and adult
males. Pods may travel together in herds of several
hundred individuals. Dominance or aggression, in the
form of a showing of teeth, tail smacking, jaw
snapping or head butting, establishes the hierarchy in
the pod.
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