Weddell Seal in its natural habitat — diving encounters and best destinations

Leptonychotes weddellii

Weddell Seal

2.5–3.5 metres
25-30 years
Least Concern

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The Weddell Seal at a glance

Diving into the pristine, frigid waters of the Southern Ocean offers a truly unique opportunity to witness one of Antarctica’s most iconic inhabitants, the Weddell seal. These magnificent marine mammals, the world's most southerly breeding mammal, are perfectly engineered for life in an extreme environment, showcasing incredible adaptations that captivate all who encounter them.

Behaviour & reproduction

Size
2.5–3.5 metres
Weight
400-600 kg
Lifespan
25-30 years
Status
Least Concern

The social structure of Weddell seals is relatively loose, centered around breeding sites on the fast ice. During the austral spring (September to November), pregnant females gather, giving birth to a single pup. These pups are born with a thick, woolly lanugo coat, typically brown or grey, which is shed after a few weeks. The bond between mother and pup is strong, with the mother fiercely protective, suckling her offspring for 5-7 weeks. Males, while generally tolerant, will establish underwater territories around breathing holes, vocally advertising their presence with an astonishing array of trills, chirps, and whistles. These vocalisations are not only for territorial defence but also play a critical role in communication during the breeding season.

Diving Tips

Encountering Weddell seals underwater is an extraordinary experience. Always maintain a respectful distance, ideally at least 5-10 meters (15-30 feet), to avoid disturbing these animals. While generally curious and not aggressive, they are powerful wild creatures. Never attempt to touch or feed a Weddell seal; this can alter their natural behavior and is illegal under the Antarctic Treaty System environmental protocols. When diving, move slowly and deliberately, avoiding sudden movements or loud noises that could startle them. Look for individuals resting on ice floes near potential dive sites, as they often slip into the water for foraging. Listen for their distinctive underwater vocalizations, which can sometimes help locate them before they come into view. Pay attention to the seals' body language; if they appear agitated or are withdrawing, increase your distance. It is crucial to have an experienced polar dive guide who understands seal behavior and local regulations. Always adhere to IAATO (International Association of Antarctic Tour Operators) guidelines and national park rules, which prioritize wildlife protection and diver safety. Remember, you are a visitor in their pristine, but fragile, environment.

Fun facts about the Weddell Seal

  • They can dive to over 600 metres and hold their breath for more than 80 minutes
  • Weddell seals maintain breathing holes in the ice by grinding with their teeth
  • Their underwater calls include trills, whistles, and chirps
  • They are the most southerly breeding mammal in the world

Best time to see the Weddell Seal

The austral summer, particularly from November to March, is generally the best time to encounter Weddell seals in Antarctica. This period offers the most accessible conditions for diving, with longer daylight hours and slightly 'warmer' water temperatures (still near freezing). November and December are prime for observing adults with newborn pups on the ice, especially around the Antarctic Peninsula and the South Shetland Islands, offering unique photographic opportunities. By January and February, pups are larger and more independent, and adult seals are frequently seen foraging. March can still offer good sightings, though ice conditions may begin to change with the onset of autumn. During these months, dive expeditions regularly visit locations such as Pleneau Island, Port Lockroy, and the Gerlache Strait, where Weddell seals are common. The presence of stable fast ice is a key indicator for encountering these seals, as it provides their preferred resting and pupping platforms.

Where the Weddell Seal lives

The Weddell seal, *Leptonychotes weddellii*, is perfectly adapted to the extreme cold of Antarctic waters, making it the world's most southerly breeding mammal. These seals are circumpolar, found throughout the Southern Ocean surrounding the Antarctic continent. They prefer areas of fast ice – sea ice attached to land – which provides stable platforms for resting, pupping, and molting. While they can be observed along the entire Antarctic coastline, particularly strong populations are found near research stations like McMurdo Station in the Ross Sea, the Antarctic Peninsula, and the South Shetland Islands. Their ability to maintain breathing holes in thick ice using their teeth is crucial for their survival in these remote, ice-covered environments, allowing them access to foraging grounds beneath the ice year-round. Divers encountering them will typically do so in shallow, coastal waters adjacent to these ice platforms, often near bays or protected coves where ice cover is consistent.

What the Weddell Seal eats

Weddell seals are opportunistic and primarily piscivorous predators, meaning their diet largely consists of fish. Their powerful jaws and robust teeth are well-suited for catching prey in their frigid environment. They consume a variety of fish species, with Antarctic silverfish (Pleuragramma antarctica) being a staple. Other common prey items include Antarctic cod (Notothenia rossii) and various other demersal and schooling fish found in the deep, cold waters under the ice. While fish constitute the bulk of their diet, they will also occasionally feed on cephalopods such as squid, and sometimes even crustaceans. They are expert pursuit hunters, using their excellent underwater vision and echolocation-like vocalizations to locate prey in the often-dark water beneath the ice. Once prey is identified, they are adept at chasing it down with surprising speed and agility for their size, capturing it with their strong jaws.

Weddell Seal: frequently asked questions

When is the best time to see Weddell Seal?
The austral summer, particularly from November to March, is generally the best time to encounter Weddell seals in Antarctica. This period offers the most accessible conditions for diving, with longer daylight hours and slightly 'warmer' water temperatures (still near freezing). November and December are prime for observing adults with newborn pups on the ice, especially around the Antarctic Peninsula and the South Shetland Islands, offering unique photographic opportunities. By January and February, pups are larger and more independent, and adult seals are frequently seen foraging. March can still offer good sightings, though ice conditions may begin to change with the onset of autumn. During these months, dive expeditions regularly visit locations such as Pleneau Island, Port Lockroy, and the Gerlache Strait, where Weddell seals are common. The presence of stable fast ice is a key indicator for encountering these seals, as it provides their preferred resting and pupping platforms.
How big does Weddell Seal get?
Weddell Seal: 2.5–3.5 metres
Is Weddell Seal dangerous for divers?
Encountering Weddell seals underwater is an extraordinary experience. Always maintain a respectful distance, ideally at least 5-10 meters (15-30 feet), to avoid disturbing these animals. While generally curious and not aggressive, they are powerful wild creatures. Never attempt to touch or feed a Weddell seal; this can alter their natural behavior and is illegal under the Antarctic Treaty System environmental protocols. When diving, move slowly and deliberately, avoiding sudden movements or loud noises that could startle them. Look for individuals resting on ice floes near potential dive sites, as they often slip into the water for foraging. Listen for their distinctive underwater vocalizations, which can sometimes help locate them before they come into view. Pay attention to the seals' body language; if they appear agitated or are withdrawing, increase your distance. It is crucial to have an experienced polar dive guide who understands seal behavior and local regulations. Always adhere to IAATO (International Association of Antarctic Tour Operators) guidelines and national park rules, which prioritize wildlife protection and diver safety. Remember, you are a visitor in their pristine, but fragile, environment.
What is the conservation status of Weddell Seal?
Weddell Seal: Least Concern
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