Common Dolphin -- Cetacean Info at Whale Songs

SCIENTIFIC NAME: Delphinus delphis

COMMON NAME: Common Dolphin from the Latin delphinus for "dolphin, porpoise;"from the Greek delphinus for "dolphin"

DISCOVERED: Linnaeus, 1758

EXTERNAL ANATOMY:

* V-shaped black/ dark gray saddle with downward oriented apex on sides directly below dorsal fin -- light gray of flanking sweeping over dorsal section of the tail of stock
* Hourglass effect on side -- tan, yellow
* Prominent dorsal fin
* Nearly black from the flipper to the lower jaw and blackline from the eye forward to the junction of the forehead and the base of the beak
* Black ring encircles the eye
* Long neck defined
* Black beak tipped with white
* Predominantly dark flippers, flukes and fin
* Maximum size: 2.6 m, 75 kg or less (male) 2.3 m, 75 kg or less (female)

GEOGRAPHICAL DISTRIBUTION:

* Widely distributed- tropical waters
* Both coastal and offshore waters
* Mediterranean Sea, Black Sea, Gulf of Mexico, Red Sea
* Enters bays, occasionally rivers
* Many follow warmer waters beyond normal range, mainly offshore

NATURAL HISTORY:

HABITAT:

* Pelagic, offshore creature
* Generally preferring surface temperatures greater than 10 degrees C

FOOD & FEEDING:

* Fish, squid or octopus, anchovies, herring and pilchards
* Small feeding groups will scatter in late afternoon to await ascension of the deep scattering layer
* Frequently adopt cooperative techniques to capture prey ex: herds may dive below a school of fish and drive it to the surface

LIFE CYCLE:

* Gestation period: 10-12 months
* Calving peaks in spring and fall
* Calf nursed 14-19 months
* Sexual maturity: 12-15 years, 1.7-2 m (male) 6- 7 years, 1.6-1.9 m (female)

BEHAVIOR:

* Various flips and somersaults
* Highly vocal- whistles pulse sounds for communication and ecolocation
* Strandings not particularly common
* Large active schools - 1000-100,000 or greater
* Friendly, but not easily trained
* Sometimes split up into small groups at night
* Reassemble to rest and socialize during the day
* Active and boisterous
* Whole school can be completely out of water
* Bow riding favorite activity - ride off ships and pressure waves created by whales - may stay with vessel long time
* Appears to be some sexual segregation- some evidence of nursery schools consisting of large portions of pregnant and nursing females
* Dive to depths of at least 280m as long as 8 minutes

WORLD POPULATION:

* Total wolrd population unknown
* Southern and Baja neritic:
* 500,000 northern stock
* 250,000 central stock
* 500-100,000 southern stock
* 28,000-285,000 in Black Sea

HUMAN INFLUENCES:

* Exploitation by man
* Entanglement in fishing nets
* Hunting/ Whaling
* Pollution
* Human disturbance