Common name: grampo
HABITAT AND GEOGRAPHICAL DISTRIBUTION
The grampo, scientific name Grampus griseus is one of the largest representatives of the large Delphinidae family. These are dolphins that are found in all temperate and tropical waters of both hemispheres, be they seas or oceans: from Newfoundland, to Norway, to the Kamchatka Peninsula, to the Gulf of Alaska to the tip of South America and the South. Africa, to get to southern Australia and New Zealand. Its area also includes the semi-closed areas of the Gulf of Mexico, the Gulf of California, the Red Sea, the Persian Gulf, the Sea of Japan and the Mediterranean Sea.
The grampo lives mainly in the deep waters off the continental slope and along the slopes of the submarine reliefs, generally between 400 m and 1000 m of depth.
The Grampo is a very large dolphin reaching 4.5 m in length. It is an unmistakable dolphin and is easily recognized as, despite being dark in color, the body has many very abundant white scars on the dorsal and lateral part of the body. These scars are thought to be the result of the combined effect of poor pigmentation of damaged tissue and a very slow healing process. From the shape and size of the scars it is assumed that they are the result of fights with other dolphins of the same species or squid stings. This peculiarity means that the older dolphins are recognized because they have an almost white body, so much is covered by scars.
The stem has a particularly rounded head, devoid of a beak, with an upper jaw without teeth, while in the lower jaw there are from 2 to 7 teeth.
A peculiarity is the presence in the front part of the head of a groove, a distinctive character for this species, which becomes larger with age and the skin that covers it is seen pulsing when the stem makes its vocalizations. The blowhole is crescent-shaped, particularly large. The eyes are relatively small and elliptical in shape, and in some individuals they are surrounded by a dark gray or black halo.
In the stem the dorsal fin is high and curved, the pectoral fins are relatively long and thin and the caudal fin is robust and allows it to reach 28-32km / h even if the average speed is 6-7 km / h.
Grampi can remain submerged for up to 30 minutes.
CHARACTER, BEHAVIOR AND SOCIAL LIFE
The stalk is a social animal that lives in groups formed on average by about thirty individuals even if they can be much more numerous (even hundreds). The size of the group is related to the presence of food: the more abundant the food, the larger the group. It has been observed that within larger groups smaller subgroups may exist, consisting of individuals with common characteristics such as sex or age.
Often the stalk is seen swimming in the company of other dolphins such as itursiopitanto that numerous hybrids have also been found grampo x bottlenose dolphin.
COMMUNICATION AND PERCEPTION
The Grampo is a dolphin that produces a wide range of sounds, including the clicks typical of echolocation (a sonar-like mechanism placed in the head that uses the reflection of sound waves, used to navigate).
Also for these dolphins it is thought that there are typical sounds for each specimen that allow each individual to be recognized.
It is well known that the diet of the stalk is based on crustaceans and cephalopods and its favorite food seems to be squid.
REPRODUCTION AND GROWTH OF THE SMALL
The stalk is not a very studied animal and not much is known about its reproductive life. Births are thought to occur during the warmer months and almost nothing is known about parental care.
STATE OF THE POPULATION
The stalk is classified in the IUNC Red list (2009.1) among animals at low risk of extinction LEAST CONCERN (LC). Although the species is classified among those not threatened it must be said that the same IUNC highlights the following threats that could cause concern: the regular hunting that is done in Japan, where about 200-500 specimens are killed every year at food purpose (although it is stated that several are caught for study purposes); in Sri Lanka, the Caribbean and Indonesia, the rasp is regularly fished, especially in Sri Lanza, for human consumption (around 1300 individuals have been estimated killed each year); off the east coast of Taiwan, significant catches are made each year.
It seems that even the grampo, like the most common dolphins, is negatively affected by loud noises of anthropogenic origin such as military sonars.
The species listed in Appendix II of CITES (Convention on International Trade in Endangered Species of Fauna and Flora, known simply as the "Washington Convention") which includes species not necessarily threatened with extinction, but whose trade must be controlled in order to avoid exploitation incompatible with their survival.
Grampo is also listed in Annex II of the CMS (Convention on Migratory Species).
They are very acrobatic animals.
Numerous hybrids of grampo dolphin x bottlenose dolphin.