Bottlenose Dolphins

Bottlenose Dolphins

Bottlenose dolphin video


This footage (link above) was taken last summer whilst returning from a power coasteering trip with Cornish Rock Tors. The dolphins followed us back into the Camel Estuary and performed a few jumps before returning to sea. You can make out their quite distinctive sickle shaped dorsal fins and darker colouring. Some of these dolphins were a good size with the largest two being 2.5 metres long by my reckoning. Click this link to read the bottlenose dolphin page on wikipedia, there is some fascinating information about their habits and biology. Particularly interesting is how dolphins sleep, how they communicate to each other, the fact they can hybridise so readily, their sight, how mothers and juveniles stay together for several years and how intelligent they are. I’ve extracted a little below.

‘Bottlenose dolphins live in groups typically of 10–30 members, called pods, but group size varies from single individuals up to more than 1,000. Their diet consists mainly of forage fish. Dolphins often work as a team to harvest fish schools, but they also hunt individually. Dolphins search for prey primarily using echolocation, which is similar to sonar. They emit clicking sounds and listen for the return echo to determine the location and shape of nearby items, including potential prey. Bottlenose dolphins also use sound for communication, including squeaks and whistles emitted from the blowhole and sounds emitted through body language, such as leaping from the water and slapping their tails on the water surface.

There have been numerous investigations of bottlenose dolphin intelligence. Research on bottlenose dolphins has examined mimicry, use of artificial language, object categorization and self-recognition. Their considerable intelligence has driven interaction with humans. Bottlenose dolphins are popular from aquarium shows and television programs such as Flipper. They have also been trained by militaries to locate sea mines or detect and mark enemy divers. In some areas, they cooperate with local fishermen by driving fish into their nets and eating the fish that escape. Some encounters with humans are harmful to the dolphins: people hunt them for food, and dolphins are killed inadvertently as a by-catch of tuna fishing.

The gestation period averages 12 months. Births can occur at any time of year, although peaks occur in warmer months.The young are born in shallow water, sometimes assisted by a (possibly male) “midwife”, and usually only a single calf is born. Twins are possible but rare. Newborn bottlenose dolphins are between 0.8–1.4 m (2.6–4.6 ft) 9–30 kg (20–66 lb) kilograms, with Indo-Pacific bottlenose dolphin infants generally smaller than common bottlenose dolphin infants. To accelerate nursing, the mother can eject milk from her mammary glands. The calf suckles for 18 to 20 months, and continues to closely associate with its mother for several years after weaning. Females sexually mature at ages 5–13, males at ages 9–14. Females reproduce every two to six years. Georgetown University professor Janet Mann argues the strong personal behavior among male calves is about bond formation and benefits the species in an evolutionary context. She cites studies showing these dolphins as adults are inseparable, and that early bonds aid protection as well as in locating females.’

Keep watching the seas.

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