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RISSO'S DOLPHIN |
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SCIENTIFIC
NAME
- Grampus
griseus from the french grand poisson "big fish" and from
the larin griseus "gray"; so "big gray fish".
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FAMILY
- Delphinidae
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| DIMENSIONS
- Medium Length 3.5 mt,
maximum 4.3 mt, the maximum weight 500 Kg. |
| ASPECT
- Body stockier of
the dolphins of equal dimensions; rounded melon with not visible rostrum; prominent upper jaw regarding lower jaw; dorsal fin
in median, high and arcuated position; lengthened pectoral fins; caudal peduncle tail thin. |
| SKIN
and COLORATION - Gray with white
scratches that render the head white, remain dark the
zones of the eyes and the fins, young clear gray, clear speck
on the abdomen. |
| LONGEVITY
- Studies Lack to care. |
| REPRODUCTION
- They reproduce in summer with gestation approximately 14 months. At the
birth puppy measure approximately 1.5 mt. |
| TEETH
- Conical and
strong, until 1.5 cm of diameter present only on lower jaw. |
| BREATH
- Little visible. |
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SOUNDS
- Three types of emissions:
1°
click, used emissions of short duration for the biosonar.
2° it
hisses modulated.
3° sounds to impulses.
The emissions of which to
number 2 and 3 they constitute the dictionary of the risso's, used in
order to communicate.
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| FEEDING
- - the diet of the Grampo is mostly
composed from cefalopod but sometimes also fish (Vd. Feeding). |
| HABITAT
- Pelagic Cetacean loves deep and moderated waters or tropical. |
| SWIM
- It's a cetacean that to the occurrence, like all the
dolphins, knows to be very fast (25 Km/h - 13 nodes) and agile, but normally it swims enough
slowly in surface with constant respiratory emersions. It is thought
is able of remarkable immersions in order to capture its preys. |
| JUMPS
- They carry out enough spectacular jumps with the total emersion of the body from the water and dive of head and on the back. Equipped of
remarkable crobatic dowries, it is exhibited as an example in
particular positions when it extracts the tail leaving in vertical
on the water for many seconds (headstanding), or when it extracts
the head looking around (spyhopping). |
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MIGRATIONS
- They make seasonal movements not Complete and own migrations. In the Mediterranean they
are present all the year.
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SOCIALITY
- They form branches of several tens of
individuals sometimes also hundreds, in the Mediterranean
approximately 16 of average. But studies lack on their sociality.
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INDOLE - Indifferent, if approached it can show distrust, sometimes
lets himself being transported from the bow wave of the boats.
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DANGER
and PREDATORY
- No assessed predator, sometimes victim of collectives beachings
given the strong branch tie, victim also of fishing-net, and the pollution
(exemplary found suffocated from plastic bag).
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SPECIES
DIFFUSION
- Do not exist careful esteem, however rather numerous. In
the Mediterranean more abundant to the West.
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