Post No. 19. Dolphins
Dolphins are a widely distributed and diverse group of
aquatic mammals. They are an informal grouping within the order cetacean,
excluding whales and porpoises, so to the zoologists the grouping is
paraphyletic. The dolphins comprise the extant families Delphinidae ( the
oceanic dolphins), Platanistidae ( the Indian river
dolphins), Iniidae ( the new world river dolphins), and POntoporiidae (the
brackish dolphins), and the extinct Lipotidae ( baiji or Chinese river
dolphin). There are 40 extant species of dolphins. Dolphins, alongside other
cetaceans, belong to the class Cetartiodactyla with even-toed ungulates. Cetaceans’
closest living relatives are the hippotamuses, having diverged about 40 million
years ago.
Dolphins range in size from the 1.7 m (5.6 ft) long and 50
kg (110 lb) Maui’s dolphin to the 9.5 m (31 ft) and 10 t (11 short tons) killer
whale. Several species exhibit sexual dimorphism, in that the males are larger
than females.
Although dolphins are widespread, most species prefer the
warmer waters of the tropic zones, but some like the right whale dolphin,
prefer colder climates. Dolphins feed largely on fish and squid, but a few like
the killer whale, feed on large mammals like seals.
Dolphins are known to teach, learn, cooperate, scheme, and
grieve. The neocortex of many species is home to elongated spindle neurons
that, prior to 2007, were known only in hominids. In humans, these cells are
involved in social conduct, emotions, judgment, and theory of mind. Cetacean
spindle neurons are found in areas of the brain that are homologous to where
they are found in humans, suggesting that they perform a similar function.
Captives have vastly reduced life expectancies, on average
only living into their 20s, although there are examples of killer whales living
longer, including several over 30 years old, and two captive orcas. While males
who survive infancy live 31 years on average, and up to 50+-60 years.
A study at the U.S. National Marine Mammal Foundation
revealed that dolphins, like humans, develop a natural form of type 2 diabetes
which may lead to a better understanding of the disease and new treatments for
both humans and dolphins.
In Greek myths, dolphins were seen invariably as helpers of
humankind. The Ancient Greeks welcomed dolphins; spotting dolphins riding in a
ship’s wake was considered a good omen. In both ancient and later art, Cupid
often shown riding a dolphin. A dolphin rescued the poet Arion from drowning
and carried him safe to land at Cape Matapan, a promontory forming the
southernmost point of the Peloponnesus . There
was a temple to Poseidon and a statue of Arion riding the dolphin.
Dolphins are sometimes hunted in places like Japan
Although dolphins generally interact well with humans, some
attacks have occurred, most of them resulting in small injuries. Orcas, the
largest species of dolphin, have been involved in fatal attacks on humans in
captivity.
Several scientists who have researched dolphin behaviour
have proposed that dolphins’ unusually high intelligence in comparison to other
animals means that dolphins should be seen as non-human persons who should have
their own specific rights and that it is morally unacceptable to keep them
captive for entertainment purposes or to kill them either intentionally for
consumption or unintentionally as by-catch. Four countries: Chile , Costa Rica ,
Hungary , and India
In some parts of the world, such as Taiji ,
Japan and the Faroe Islands , dolphins are traditionally considered as
food, and are killed in harpoon or drive hunts. Dolphin meat is consumed in a
small number of countries worldwide, which include Japan
and Peru Japan
Dolphin meat is dense and such a dark shade of red as to
appear black. Fat is located in a layer of blubber between the meat and the
skin. When dolphin meat is eaten in Japan
There have been human health concerns associated with the
consumption of dolphin meat in Japan Faroe
Islands , where prenatal exposure to methylmercury and PCBs
primarily from the consumption of pilot whale meat has resulted in
neuropsychological deficits amongst children. (Wikipedia)
Richard “Ric” O’Barry is an American activist and founder of
the Dolphin Project. His purpose is to educate the public about captivity and
if possible to free captive dolphins.
References.
Ocean Stories 3- Dolphins and Whales. Time: 48:30:
Dolphins Even Smarter Than You Thought I Nat Geo Live. Time:
16:51:
Could we speak the language of dolphins I Denise Herzing.
Time: 14:38:
Denise Herzing: “ Dolphin Communication: Cracking the Code”
I Tals at Google. Time: 54:40:
The Complete 2017 SeaWorld “Bllue Horizons” Dolphin Show. Time:
23:34:
Dolphin Hero/ Academy Awared Winner Ric O’Barry: An Urgent Must
Listen! The Carol Rosin Show 5-19-17. Time: 1:48:12:
Terrified Dolphin Throws Himself At Ric O’Barry’s Feet to
Escape Hunters. Time: 6:11:
The dolphin hunt in Taiji continues. Time: 4:26:
Pilot whale slaughter: Annual hunt sees 160 dolphins
butchered in the Faroe Islands-TomNews. Very Graphic. Time: 5:07:
The Best Relax Music and Dolphin Aquarium – Sleep Relaxing
Music. 2 Hours- HD 1080p. Time: 1:59:59:
This is a personal photo. It was taken during my last visit to the Seaquarium located in Miami, Florida, about three years ago.
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