Hourglass Dolphin

Fascinating facts about the Hourglass Dolphin

• Each side of the hourglass dolphin bears a white patch near the beak, eye and flipper and a second one toward the rear; the two are linked by a thin white strip that forms a loose hour-glass silhouette. This striking pattern is the reason the animal received its common name. The markings differ from dolphin to dolphin, so no two individuals look exactly alike.
• Hourglass dolphins stay near the ocean surface because they favour cold water, typically encountering temperatures from just below zero to about seven degrees Celsius. On rare occasions they have been recorded in water as warm as fourteen degrees Celsius. Their seasonal movements see them travel farther south during the austral summer and shift northward in the austral winter. This pattern keeps them within their preferred thermal envelope throughout the year.
• In most encounters hourglass dolphins travel in modest groups of ten to fifteen individuals, making them relatively easy to spot. Occasionally, observers have documented spectacular aggregations of up to one hundred animals gathering together. Such large gatherings are far less common than the typical small pods. The species' social flexibility allows it to form both intimate groups and occasional massive assemblies.
• Surveys carried out in the late 1970s and again in the late 1980s counted about 144,300 hourglass dolphins, using line-transect sightings taken in January 1977 and January 1988 in northern Antarctic waters. Subsequent monitoring shows the numbers have slipped slightly since 1988, yet the species is not regarded as endangered. This modest decline is reflected in its classification as Least Concern on the IUCN Red List.
• The hourglass dolphin's dorsal fin shows noticeable individual variation, with many adults possessing a tall, curved fin. In older dolphins the curve becomes especially pronounced, creating a distinct silhouette that helps separate them from the southern right whale dolphin, which lacks a dorsal fin altogether. This fin morphology, together with their striking colour pattern, makes the species readily identifiable in its Antarctic range.

Sources

Every fact above was checked against these pages, and kept only where one of them states it.

• Wikipedia

At a glance

About the Hourglass Dolphin

In the icy waters of the Southern Ocean, the hourglass dolphin dances with effortless elegance, its sleek, black-and-white form slicing through the waves with a fluidity that belies its robust physique. As it moves, the dolphin's distinctive hourglass pattern seems to shimmer and glow, a mesmerizing display of adaptive camouflage that allows it to thrive in this harsh, yet beautiful, environment. With its acrobatic leaps and playful nature, the hourglass dolphin is a joyful embodiment of the ocean's untamed spirit.

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