Leopard seal, Brighton Estuary

Image: C. S. Robertson | DOC

Introduction

Leopard seals primarily inhabit the Antarctic pack ice, but during autumn and winter animals disperse northward throughout the Southern Ocean, sometimes visiting New Zealand. Some animals have been known to spend a year or more continuously in New Zealand waters.

Facts

The leopard seal (Hydrurga leptonyx) is easily identified by its long slim body and comparatively large fore-flippers. The leopard seal’s disproportionately large head, massive jaws, impressive teeth and tremendous gape give it a snake-like appearance.

In colour, the leopard seal shades from almost black to almost blue on the flanks. The muzzle, throat and belly are light grey scattered with dark grey and black spots. The demarcation between dorsal and ventral colouration is distinct but diffuse. Pup appearance is very similar to that of the adults.

Their underwater vocalisations are of low to medium frequency and long duration. The leopard seal’s lowest frequency call is particularly powerful and can be heard at the surface and felt through the ice.

Newborn pups are more than 1 m long and may weigh close to 30kg. Females grow faster than males and very large individuals can weigh up to 450 kg.

Adult females: length 3.6 m, weight up to 500 kg
Adult males: length 3 m, weight up to 300 kg

Range

Leopard seals primarily inhabit the Antarctic pack ice but, during autumn and winter animals disperse northward throughout the Southern Ocean, sometimes visiting New Zealand. Auckland and Campbell islands are known to have leopard seals annually and the mainland regularly receives visitors. 

Population

A population estimate in 1977 put the total number at 222,000-440,000 worldwide. It is unknown how many individuals visit/inhabit New Zealand waters.

Diet and foraging

Leopard seals prey on a variety of species, including krill, penguins, birds, fish, seals and cephalopods. It is likely that they are opportunistic in that they prey on whatever is readily available.

They are the only seals known to regularly hunt and kill warm-blooded prey, including other seals. Although rare, there are a few records of adult leopard seals attacking humans.  There has also been one fatality, when a researcher was snorkelling in Antarctic waters and was killed by a leopard seal.

Leopard seals frequent ice-floes and waters adjacent to Adelie penguin rookeries and are adept at catching penguins after underwater pursuits or as they fall back into the water after missing their footing on the ice. Penguins are skinned by the seal gripping the skin with its incisor teeth and shaking the bird until the skin tears away.

Breeding

Leopard seals are usually solitary animals. Males are sexually mature at 3-6 years of age and females at 2-7 years. Mating has never been observed in the wild. Adults moult between January and June.

Leopard seals appear to have low productivity compared to other seals, with only 50-60 per cent pupping annually. Pups are born mainly in the pack ice in November and the reproductive season ends in late December. Lactation lasts for one month. Males are rarely seen near pupping and nursing sites.

Threats

Human impact

Leopard seals have never been systematically exploited. Currently they are protected under the Convention for the Conservation for Antarctic Seals (1972) limiting kill to 12,000 in any one year.

Further threats include the entanglement in marine debris and harassment by the public and dogs.

IUCN Red List of Threatened Species status: Least Concern.

Predators

Killer whales are known to occasionally predate upon leopard seals.  It is likely that larger sharks may also predate on them, although no evidence yet exists to support this theory.

DOC's work

Leopard seals are protected under the Wildlife Act 1953 and the Marine Mammals Protection Act 1978.

DOC records all sighting and incident information in the National Marine Mammal Database. This adds to the pool of information that is available for this species.

Report sightings of leopard seals

You can report sightings of seals to our conservation hotline 0800 DOC HOT (0800 362 468) or on 0800 LEOPARD (0800 536 7273). You can also report a sighting online to DOC or on Leopard Seal Sightings NZ Facebook page

Reports of sightings are always valuable and help increase our knowledge of leopard seal occurrence and movements around New Zealand. Individual leopard seals can also be tracked using photo identification.

Record the details

Include as much information as possible with your sighting:

  • the date, time and location (GPS coordinates if possible - your phone can store these when you take a photo, if you have the location setting enabled)
  • the number of seals and estimated sizes
  • take photographs or videos if possible

Call the DOC conservation emergency hotline 0800 DOC HOT (0800 362 468) if you see a seal that is:

  • severely injured
  • entangled in marine debris
  • being harassed by people or dogs 

How to approach seals

Seals are wild animals and will defend themselves if they feel threatened. While they can look harmless, leopard seals can swivel around very quickly from their resting position to attack and can inflict serious injuries to dogs or people. They also can carry infectious diseases.

Follow these simple guidelines when watching seals for your safety and that of the animals:

  • stay at least 20 m away
  • don’t disturb seals by making loud noises or throwing things
  • keep dogs and children away 
  • don’t feed the seals
  • never attempt to touch a seal.

It is an offence under the Marine Mammals Protection Act 1978 (MMPA) to disturb, harass, harm, injure or kill a seal. A dog owner whose dog attacks a seal could face prosecution. Anyone charged under the MMPA with harassing, disturbing, injuring or killing a seal faces a maximum penalty of two years’ imprisonment or a fine to a maximum of $250,000. 

If you accidentally catch or harm a seal

You must report it as soon as possible to our conservation hotline 0800 DOC HOT (0800 362 468) or the Ministry for Primary Industries (0800 008 333).

If the seal is alive you should release it back into the water as quickly and gently as possible, provided it is safe to do so. Be particularly careful with seals as they may be aggressive and bite.

If the seal is dead, either release the carcass at sea or preferably bring it to shore for us to recover. 

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