دلفین دلفین پستاندار دریایی از رده آب‌بازان میباشد.
خانواده دلفین با ۱۷ جنس و ۳۵ گونه بزرگترین خانواده زیر راسته نهنگهای دندان دار محسوب میشود.اعضای این خانواده در تمام آبهای آزاد جهان و همچنین بعضی رودخانه‌های در امتداد آب شیرین انتشار دارند.این خانواده از دوره آئوسن ظاهر شده‌اند.
پوست بدن دلفینها معمولاً صاف و برهنه‌است.
ممکن است در سر و تنه تعدادی از آنها مو وجود داشته باشد.
از گوشهای خارجی فقط سوراخ کوچکی نمایان است و سوراخ بینی که یک یا دو عدد می‌باشند در بالا و عقب سر قرار گرفته‌اند تا عمل تنفس در سطح آب را سهولت بخشند این سوراخها به‌وسیله پرده‌ای خود به خود بسته می‌شوند.
تعداد دندانها زیاد و در بعضی گونه‌ها به ۲۶۰ عدد می‌رسد و عمدتاً از ماهیها و سرپایان و حتی دلفینهای کوچک‌تر تغذیه می‌کنند.
طول آنها از ۲/۱ الی ۹/۳ متر و وزنشان از ۲۳ تا ۱۳۶ کیلوگرم متفاوت گزارش شده‌است.
دانشمندان بر این باورند که هنگامی که یک دلفین می‌خوابد فقط نیمی از مغز او استراحت می‌کند نیمه دیگر بیدار باقی می‌ماند تا دلفین به شکل طبیعی عمل کند پس از مدتی، دو نیمه مغز کارهایشان را با هم عوض می‌کنند.
] دلفین بینی بطری دلفین بینی بطری (Bottlenose)از گونه دلفینهایی است که به وفور در اکواریومهای دنیا جهت عملیات نمایشی به کار گرفته میشود.
از نقطه نظر پراکندگی در اکثر اقیانوسهای جهان از جمله خلیج فارس وجود دارد با وزنی در حدود ۲۵۰ تا۶۰۰کیلوگرم طولی معادل ۲تا۴ متر و ردیف دندانهایی که در هر ارواره از ۲۲تا۲۶ دندان تشکیل شده تقزیبا هر ۲ سال یک بار بچهدار میشود و دلفینی به طول۱متر و وزنی معادل ۳۷ کیلوگرم را به مدت ۱سال با شیر مادر تغذیه می‌کند و طول عمری معادل ۲۶ تا۳۰ سال دارد.
] دلفین سیاه دلفین سیاه گونه‌ای از خانواده نهنگهای خلیج فارس میباشد که رنگ تیره بدن وی را از سایر گونه‌های این خلیج جدا میسازد رنگی بین خاکستری تیره مایل به سیاه البته بسیاری از دلفینها پس از مرگ رنگ پوست را با این رنگ تعویض می‌کنند که شاید موجبات اشتباه را هم فراهم کند.
دلفین سیاه به دندانهایی با قطر بیش از ۲۵ میلیمتر مجهرند که به نوعی در برخی موارد حمله اینگونه به دیگر دلفینها را فراهم میآورد اما عمدتاً به علت سرعت کمتر در قیاس با سایر هم گونه‌ها ناکام می‌ماند.
از نقطه نظر پراکندگی در اکثر دریاهای گرم و معتدل جهان از جمله خلیج فارس یافت میشود.
همچنین وزنی معادل ۲تن و طولی بین ۴ تا ۶متر و زمان باروروری ۱۵ ماه و زادآوری بجه دلفینی معادل ۲ متر از دیگر ویژگیهای این گونه محسوب میشود.
] دلفین یونس دلفین یونس (نهنگ یونس) نوعا گونه منزوی شناخته میشود ؛ نهنگ یونس دارای طولی معادل ۳تا ۴ متر می‌باشدو وزنی حدود۴۰۰ تا ۴۳۰ کیلوگرم دارد.این دلفین دارای مجموعا ۹ دندان با رنگی خاکستری تیره که به مرور و در اثر افزایش سن روشن تر می‌گردد، به همراه خطوطی نامنظم بر روی پوست است.
روایت می‌کنند که یونس پیامبر آن هنگام که امر خدا را ترک کرد، در سفری دریایی کشتی او در میان طوفان گرفتار شد و یونس پیامبر توسط نهنگی بلعیده شد.
برگرفته از » Dolphin From Wikipedia, the free encyclopedia Jump to: navigation, search For other uses, see Dolphin (disambiguation).
Dolphins Fossil range: Early Miocene - Recent Bottlenose Dolphin breaching in the bow wave of a boat Scientific classification Kingdom: Animalia Phylum: Chordata Class: Mammalia Order: Cetacea Suborder: Odontoceti Family: Delphinidae and Platanistoidea Gray, 1821 Genera See article below.
Dolphins are marine mammals that are closely related to whales and porpoises.
There are almost forty species of dolphin in seventeen genera.
They vary in size from 1.2 metres (4 ft) and 40 kilograms (88 lb) (Maui's Dolphin), up to 9.5 m (30 ft) and ten tonnes (the Orca or Killer Whale).
They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating fish and squid.
The family Delphinidae is the largest in the Cetacea, and relatively recent: dolphins evolved about ten million years ago, during the Miocene.
Dolphins are considered to be amongst the most intelligent of animals and their often friendly appearance and seemingly playful attitude have made them popular in human culture.
Contents [hide] 1 Origin of the name 2 Taxonomy 2.1 Hybrid dolphins 3 Evolution and anatomy 3.1 Evolution 3.2 Anatomy 3.3 Senses 4 Behaviour 4.1 Social behaviour 4.2 Reproduction and sexuality 4.3 Feeding 4.4 Vocalizations 4.5 Jumping and playing 4.6 Sleeping 5 Threats to dolphins 5.1 Natural threats to dolphins 5.2 Human threats to dolphins 6 Human–dolphin relationships 6.1 Mythology 6.2 Entertainment 6.3 Therapy 6.4 Rescue and rehabilitation 6.5 Military 6.6 Literature 6.7 Dauphin and Dauphiné 7 References 8 External links Origin of the name The name is originally from Ancient Greek δελφίς (delphís; "dolphin"), which was related to the Greek δελφύς (delphys; "womb").
The animal's name can therefore be interpreted as meaning "a 'fish' with a womb".[1] The name was transmitted via the Latin delphinus, Middle Latin dolfinus and the Old French daulphin, which reintroduced the ph into the word.
The word is used in a few different ways.
It can mean: · Any member of the family Delphinidae (oceanic dolphins), · Any member of the families Delphinidae and Platanistoidea (oceanic and river dolphins), · Any member of the suborder Odontoceti (toothed whales; these include the above families and some others), · Used casually as a synonym for Bottlenose Dolphin, the most common and familiar species of dolphin.
In this article, the second definition is used.
Porpoises (suborder Odontoceti, family Phocoenidae) are thus not dolphins in this sense.
Orcas and some closely related species belong to the Delphinidae family and therefore qualify as dolphins, even though they are called whales in common language.
A group of dolphins can be called a "school" or a "pod".
Male dolphins are called "bulls", females "cows" and young dolphins are called "calves".[2] Taxonomy Common Dolphin Bottlenose Dolphin Spotted Dolphin Commerson's Dolphin Dusky Dolphin Killer Whales, also known as Orcas The Boto, or Amazon River Dolphin · Suborder Odontoceti, toothed whales o Family Delphinidae, oceanic dolphins § Genus Delphinus § Long-Beaked Common Dolphin, Delphinus capensis § Short-Beaked Common Dolphin, Delphinus delphis § Genus Tursiops § Bottlenose Dolphin, Tursiops truncatus § Indo-Pacific Bottlenose Dolphin, Tursiops aduncus § Genus Lissodelphis § Northern Rightwhale Dolphin, Lissodelphis borealis § Southern Rightwhale Dolphin, Lissiodelphis peronii § Genus Sotalia § Tucuxi, Sotalia fluviatilis § Genus Sousa § Indo-Pacific Hump-backed Dolphin, Sousa chinensis § Chinese White Dolphin (the Chinese variant), Sousa chinensis chinensis § Atlantic Humpbacked Dolphin, Sousa teuszii § Genus Stenella § Atlantic Spotted Dolphin, Stenella frontalis § Clymene Dolphin, Stenella clymene § Pantropical Spotted Dolphin, Stenella attenuata § Spinner Dolphin, Stenella longirostris § Striped Dolphin, Stenella coeruleoalba § Genus Steno § Rough-Toothed Dolphin, Steno bredanensis § Genus Cephalorynchus § Chilean Dolphin, Cephalorhynchus eutropia § Commerson's Dolphin, Cephalorhynchus commersonii § Heaviside's Dolphin, Cephalorhynchus heavisidii Hector's Dolphin, Hector's Dolphin, Cephalorhynchus hectori Genus Grampus Risso's Dolphin, Grampus griseus Genus Lagenodelphis Fraser's Dolphin, Lagenodelphis hosei Genus Lagenorhyncus Atlantic White-Sided Dolphin, Lagenorhynchus acutus Dusky Dolphin, Lagenorhynchus obscurus Hourglass Dolphin, Lagenorhynchus cruciger Pacific White-Sided Dolphin, Lagenorhynchus obliquidens Peale's Dolphin, Lagenorhynchus australis White-Beaked Dolphin, Lagenorhynchus albirostris Genus Orcaella Australian Snubfin Dolphin, Orcaella heinsohni Irrawaddy Dolphin, Orcaella brevirostris Genus Peponocephala Melon-headed Whale, Peponocephala electra Genus Orcinus Killer Whale (Orca), Orcinus orca Genus Feresa Pygmy Killer Whale, Feresa attenuata Genus Pseudorca False Killer Whale, Pseudorca crassidens Genus Globicephala Long-finned Pilot Whale, Globicephala melas Short-finned Pilot Whale, Globicephala macrorhynchus Family Platanistoidea, river dolphins Genus Inia Boto (Amazon River Dolphin), Inia geoffrensis Genus Lipotes Chinese River Dolphin (Baiji), Lipotes vexillifer (considered functionally extinct) Genus Platanista Ganges River Dolphin, Platanista gangetica Indus River Dolphin, Platanista minor Genus Pontoporia La Plata Dolphin (Franciscana), Pontoporia blainvillei Six species in the family Delphinidae are commonly called "whales" but are strictly speaking dolphins.
They are sometimes called "blackfish".
Melon-headed Whale, Peponocephala electra Killer Whale, Orcinus orca Pygmy Killer Whale, Feresa attenuata Wolphin Kawili'Kai at the Sea Life Park in Hawaii.
False Killer Whale, Psudorca crassidens Long-finned Pilot Whale, Globicephala melas Short-finned Pilot Whale, Globicephala macrorhynchus Hybrid dolphins In 1933, three abnormal dolphins were beached off the Irish coast; these appeared to be hybrids between Risso's Dolphin and the Bottlenose Dolphin.[3] This mating has since been repeated in captivity and a hybrid calf was born.
In captivity, a Bottlenose Dolphin and a Rough-toothed Dolphin produced hybrid offspring.[4] A Common-Bottlenose hybrid lives at SeaWorld California [5] and another one lives at Discovery Cove in Orlando.
Various other dolphin hybrids have also been reported in the wild, such as a Bottlenose-Atlantic Spotted hybrid.[6] The best known hybrid however is the Wolphin, a False Killer Whale-Bottlenose Dolphin hybrid.
The Wolphin is a fertile hybrid, and two such Wolphins currently live at the Sea Life Park in Hawaii, the first having been born in 1985 from a male False Killer Whale and a female Bottlenose.
Wolphins have also been observed in the wild.[7] Evolution and anatomy The Anatomy of a Dolphin showing its skeleton, major organs and body shape.
Evolution See also: Evolution of cetaceans Dolphins, along with whales and porpoises, are descendants of terrestrial mammals, most likely of the Artiodactyl order.
The ancestors of the modern day dolphins entered the water roughly fifty million years ago, in the Eocene epoch.
Hind Limb Buds on Dolphins An embryo of a Spotted Dolphin in the fifth week of development.
The hind limbs are present as small bumps (hind limb buds) near the base of the tail.
The pin is approximately 1 inch (~2,5 cm) long.
Bottlenose Dolphin with vestigial hind flippers, captured 2006 in Japan.
Modern dolphin skeletons have two small, rod-shaped pelvic bones thought to be vestigial hind legs.
In October 2006 an unusual Bottlenose Dolphin was captured in Japan; it had small fins on each side of its genital slit which scientists believe to be a more pronounced development of these vestigial hind legs.[8] Anatomy Dolphins have a streamlined fusiform body, adapted for fast swimming.
The tail fin, called the fluke, is used for propulsion, while the pectoral fins together with the entire tail section provide directional control.
The dorsal fin, in those species that have one, provides stability while swimming.
Though it varies per species, basic colouration patterns are shades of grey usually with a lighter underside.
It is often combined with lines and patches of different hue and contrast.
The head contains the melon, a round organ used for echolocation.
In many species, the jaws are elongated, forming a distinct beak; for some species like the Bottlenose, there is a curved mouth which looks like a fixed smile.
Teeth can be very numerous (up to two hundred and fifty) in several species.
Dolphins breathe through a blowhole located on top of their head, with the trachea being anterior to the brain.
The dolphin brain is large and highly complex and is different in structure from most land mammals.
Unlike most mammals, dolphins do not have hair, but they are born with a few hairs around the tip of their rostrum which they lose shortly after birth, in some cases even before they are born.[9] The only exception to this is the Boto river dolphin, which does have some small hairs on the rostrum.[10] Their reproductive organs are located on the underside of the body.
Males have two slits, one concealing the penis and one further behind for the anus.
The female has one genital slit, housing the vagina and the anus.
A mammary slit is positioned on either side of the female's genital slit.
Senses Most dolphins have acute eyesight, both in and out of the water, and their sense of hearing is superior to that of humans.
Though they have a small ear opening on each side of their head, it is believed that hearing underwater is also if not exclusively done with the lower jaw which conducts the sound vibrations to the middle ear via a fat-filled cavity in the lower jaw bone.
Hearing is also used for echolocation, which seems to be an ability all dolphins have.
Their teeth are arranged in a way that works as an array or antenna to receive the incoming sound and make it easier for them to pinpoint the exact location of an object.[11] The dolphin's sense of touch is also well-developed, with free nerve endings being densely packed in the skin, especially around the snout, pectoral fins and genital area.
However, dolphins lack an olfactory nerve and lobes and thus are