INTRODUCTION
 Dolphins are highly intelligent marine mammals and are part of the family of
toothed whales that includes orcas and pilot whales
 There are 40 extant species named as dolphins.
 Name derived from Greek word delphis, meaning womb.

Common bottlenose dolphin
KINGDOM : Animalia
PHYLUM : Chordata
CLASS : Mammalia
ORDER : Cetacea
FAMILY : Delphinidae
GENUS : Tursiops
SPECIES : T. truncatus

BOTTLENOSE DOLPHINS
 Most common species
 Familiar due to exposure they receive in captivity,
movies and programmes
 Largest species of beaked dolphins
 Inhabit temperate and tropical oceans and absent
from polar waters
 Distribution is generally limited to surface water
temperatures of 10° to 32°C (50° to 90° F).

 Habitat is usually warm temperate waters and they are greatly
adapted to survive in marine, estuarine as well as river waters.
 They are not endangered or threatened
 Worldwide population is about 6,00,000.
 Median life spans between 8.3 and 17.4 years in wild and about 22.8
years in captivity.
 As a dolphin ages, it periodically produces growth layer groups
(GLGs) of dental material. Age can be estimated by examining a sliced
section of a tooth and counting these layers.
 Dolphins spent about 33% of each day sleeping

PHYSICAL CHARACTERISTICS
 In general, 2 to 3.9 m (6.6 to 12.8 ft.) long
 Males and females almost similar in appearance but males weigh twice as much as
females
 Avg. weight is 150-200kg for a female while about 400kg for male
 Body is streamlined, sleek and fusiform
 Skin is smooth and rubbery without hairs and sweat glands
 Skin colour- grey to dark grey on back; white on lower jaw and belly
 Blubber present below the dermis
 The rounded region of a dolphin's forehead is called the melon.

 Well-defined rostrum (snout-like projection) in front of the melon.
 Teeth are conical and interlocking.
 Teeth are designed for grasping (not chewing) food.
 Bottlenose dolphins have 18 to 26 teeth on each side of the upper and lower jaws, a total of
72 to 104 teeth.
 Eyes are on the sides of the head, near the corners of the mouth.
 A bottlenose dolphin breathes through its blowhole. It is usually covered with muscular
flap

SENSES
 They have a larger brain size than same sized mammals
 This may be due to an increased size of the auditory region to facilitate sound processing.
 Thus, dolphins have a well-developed, acute sense of hearing.
 They can hear tones with a frequency up to 160 kHz with the greatest sensitivity ranging
from 40 to 100 kHz (humans only up to 20kHz)
 Acute vision- adapted for underwater vision mainly.
 Primarily monocular
 Skin sensitive to vibrations
 Taste buds at base of tongue- can detect 3 or 4 primary tastes (sweet, bitter, sour, salty)
 May not have sense of smell

COMMUNICATION
 Sound production to navigate, communicate, hunt, and
avoid predators in dark or limited vision waters.
 Produced by air movements in the nasal passage.
 Tissue complex called dorsal bursa- phonic lips- tissue
vibrations produce sound
 Can be clicks, squeaks, whistles etc
 identifies itself with a signature whistle
 A mother dolphin may whistle to her calf almost
continuously for several days after giving birth.

ECHOLOCATION
 By producing clicking sounds and then receiving and interpreting the resulting
echo.
 By this, dolphins can determine size, shape, speed, distance, direction, and even
some of the internal structure of objects in the water.

FOOD
 During early morning and late afternoon
 Predators- eat wide variety of fishes, squids, and crustaceans such as shrimps
 Adult bottlenose dolphins eat approximately 4% to 6% of their body weight in food
per day.
 A nursing mother's daily intake is considerably higher — about 8%.
 A dolphin's stomach is compartmentalized for rapid digestion.
 Hunting techniques include pinwheeling, drivers and blockers, strand feeding etc
 Dolphins do not chew their food
 Before eating large fishes, bottlenose dolphins shake them or rub them on the
ocean floor until suitable-size pieces break off.

feeding

REPRODUCTION
 Females reach sexual maturity at 7 to 10 years and
males at 7-12 years
 Breed throughout the year
 Females ovulate 2-7 times and both sexes have multiple
mates
 Births may occur in all seasons, but typically peaks
occur during spring, early summer and fall.
 During courtship, dolphins engage in head-butting and
tooth-scratching.
 Gestation period is about 12 months

 A female dolphin can potentially bear a calf every two
years
 Calves are born in the water
 Assisting dolphin seen near mother and calf- auntie
dolphin- can be male as well
 Calf is about 10-20kg at birth
 A calf may nurse for up to 18 to 24 months
 The calf suckles from nipples concealed in abdominal
mammary slits.
 Calves begin to take a few fish at about 3 to 4 months
 Mother-calf bonds are long-lasting; a calf typically stays
with its mother 3 to 6 years.

BEHAVIOUR
 Bottlenose dolphins live in fluid social groups.
 Primarily found in 2-15 individuals per group
 These communities around the world are described as “fission-fusion” societies.
 Bottlenose dolphin females form alliances primarily to obtain food resources and for
reproduction
 Establish and maintain dominance through posturing, biting, chasing, jaw clapping,
smacking their tails on the water, emitting bubble clouds from their blowholes
 Large adult male- protection, scouting
 Aid injured dolphins and often seen with other toothed whales

THREATS
 Variety of diseases and parasites can be responsible for dolphin deaths.
 Natural predators include certain large shark species such as tiger sharks
(Galeocerdo cuvier), dusky sharks (Carcharhinus obscurus), bull sharks
(Carcharhinus leucas), and great white sharks (Carcharhinus carcharias).
 They are affected by heavy boat traffic, habitat loss and pollution.
 Bottlenose dolphins have been taken directly for meat, leather, oil, and meal (for
fertilizer and animal feed) in Peru, Japan etc.
 In the course of fishing operations, gear and nets can accidentally entangle and
injure or drown dolphins.

CONSERVATION
 The International Whaling Commission
 IUCN/The World Conservation Union Species Survival Commission
(SSC)
 The Convention on International Trade in Endangered Species of Wild
Fauna and Flora (CITES)- listed in appendix II
 The Marine Mammal Protection Act (MMPA)
 U.S. Dolphin Protection Consumer Information Act (DPCIA)
 Marine life Parks
 The SeaWorld & Busch Gardens Conservation Fund

IWC- To protect small cetaceans and whales Seaworld created nutritional formulas
for orphan animals
 The non-profit SeaWorld & Busch Gardens Conservation Fund(SWBGCF) is committed to species
research, habitat protection, animal rescue, and conservation education.

WINTER- THE DOLPHIN