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Hourglass dolphin
The hourglass dolphin (Cephalorhynchus cruciger) is a small dolphin in the family Delphinidae that inhabits offshore Antarctic and sub-Antarctic waters. It is commonly seen from ships crossing the Drake Passage but has a circumpolar distribution.
The species was identified as a new species by Jean René Constant Quoy and Joseph Paul Gaimard in 1824 from a drawing made in the South Pacific in 1820. It is the only cetacean to have been widely accepted as a species solely on witness accounts.
The hourglass dolphin is colored black on top and white on the belly, with white patches on the sides and sometimes variations of dark grey. For this reason, it was colloquially known by whalers as a "sea cow" (although it does not belong to the taxonomic order Sirenia) or "sea skunk". Each flank has a white patch at the front, above the beak, eye and flipper, and a second patch at the rear. These two patches are connected by a thin white strip, creating, loosely speaking, an hourglass shape; hence the common name of the dolphin. The markings can vary between individuals. The scientific name cruciger means "cross-carrier" and refers to the area of black coloration, which, viewed from above, vaguely resembles a Maltese cross or cross pattée.
In its usual range the dolphin is easily identifiable. The southern right whale dolphin is the only cetacean of comparable size and comparable coloration with overlapping distributions that lives as far south. The absence of a dorsal fin in right whale dolphins, in contrast to the generally tall and curved dorsal fin of hourglass dolphins makes confusion of the two species very unlikely. The dorsal fin in hourglass dolphins is variable and the curvature may be particularly pronounced in older animals. The hourglass dolphin has disk-shaped vertebrae and other inclined processes which gives them higher stability.
An adult male is about 1.8 meters (5.9 feet) in length and weighs over 90 kilograms (about 200 lbs). Juvenile females range from 1.6 to 1.8 meters (5.2 to 5.9 ft) in length and weigh from 70 to 90 kg (150 to 200 lb). Although this species is small, they are extremely fast and agile. Males are thought to be slightly smaller and lighter than females, although the small number of specimens does not permit a firm conclusion.
Female gestation periods are estimated to be 12.9 months and they tend to give birth between mid to late July through October.
An hourglass dolphin has 26 to 34 teeth in their upper jaw and 27 to 35 teeth in their lower jaw. Like all species of dolphins, they use echolocation to find food. There have been no verified sightings of calves and their coloration, size, and diet remains unknown.
The range is circumpolar from close to the Antarctic pack ice to about 45°S. The northernmost confirmed sightings are 36°S in the South Atlantic Ocean and 33°S near Valparaíso, Chile, in the Pacific. The overall circumpolar distribution is about 45°S to 67°S, with few sightings made near islands and the majority in the Southern ocean. Sightings have been made most commonly from the south of New Zealand, around the South Shetland Islands and off Tierra del Fuego, Argentina.
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Hourglass dolphin AI simulator
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Hourglass dolphin
The hourglass dolphin (Cephalorhynchus cruciger) is a small dolphin in the family Delphinidae that inhabits offshore Antarctic and sub-Antarctic waters. It is commonly seen from ships crossing the Drake Passage but has a circumpolar distribution.
The species was identified as a new species by Jean René Constant Quoy and Joseph Paul Gaimard in 1824 from a drawing made in the South Pacific in 1820. It is the only cetacean to have been widely accepted as a species solely on witness accounts.
The hourglass dolphin is colored black on top and white on the belly, with white patches on the sides and sometimes variations of dark grey. For this reason, it was colloquially known by whalers as a "sea cow" (although it does not belong to the taxonomic order Sirenia) or "sea skunk". Each flank has a white patch at the front, above the beak, eye and flipper, and a second patch at the rear. These two patches are connected by a thin white strip, creating, loosely speaking, an hourglass shape; hence the common name of the dolphin. The markings can vary between individuals. The scientific name cruciger means "cross-carrier" and refers to the area of black coloration, which, viewed from above, vaguely resembles a Maltese cross or cross pattée.
In its usual range the dolphin is easily identifiable. The southern right whale dolphin is the only cetacean of comparable size and comparable coloration with overlapping distributions that lives as far south. The absence of a dorsal fin in right whale dolphins, in contrast to the generally tall and curved dorsal fin of hourglass dolphins makes confusion of the two species very unlikely. The dorsal fin in hourglass dolphins is variable and the curvature may be particularly pronounced in older animals. The hourglass dolphin has disk-shaped vertebrae and other inclined processes which gives them higher stability.
An adult male is about 1.8 meters (5.9 feet) in length and weighs over 90 kilograms (about 200 lbs). Juvenile females range from 1.6 to 1.8 meters (5.2 to 5.9 ft) in length and weigh from 70 to 90 kg (150 to 200 lb). Although this species is small, they are extremely fast and agile. Males are thought to be slightly smaller and lighter than females, although the small number of specimens does not permit a firm conclusion.
Female gestation periods are estimated to be 12.9 months and they tend to give birth between mid to late July through October.
An hourglass dolphin has 26 to 34 teeth in their upper jaw and 27 to 35 teeth in their lower jaw. Like all species of dolphins, they use echolocation to find food. There have been no verified sightings of calves and their coloration, size, and diet remains unknown.
The range is circumpolar from close to the Antarctic pack ice to about 45°S. The northernmost confirmed sightings are 36°S in the South Atlantic Ocean and 33°S near Valparaíso, Chile, in the Pacific. The overall circumpolar distribution is about 45°S to 67°S, with few sightings made near islands and the majority in the Southern ocean. Sightings have been made most commonly from the south of New Zealand, around the South Shetland Islands and off Tierra del Fuego, Argentina.