Elephant seal

Southern elephant seals occasionally visit local coastlines of mainland New Zealand, but are residents of New Zealand’s subantarctic islands. On mainland they may stay in an area for months, giving people an opportunity to observe animals that normally live in sub-antarctic waters.

The grace and speed of such large marine mammals can be an impressive sight, and young seals can be very playful. Enjoy their visits, but remember they are wild animals, and should be respected as such.

Facts

The southern elephant seal (Mirounga leonina) is the largest species of seal in the world. They are dark grey immediately after moulting, fading through the year to a rusty greyish brown.

Their most outstanding feature is the inflatable proboscis (snout) which reaches full development in adult males, and is thought to increase the effectiveness of the bull elephant seal's roar.

Elephant seals use their teeth during fighting to rake the necks of opponents. Large bulls can be heavily scarred from fights with other males during the breeding season. The nails on their forelimbs help the elephant seal climb over rocks and are also used for scratching dry skin and irritation caused by parasites.

Adult males: length 4-5 m, weight 3,600 kg
Adult females: length 2-3 m, weight 900 kg

Range

Southern elephant seals range throughout the Southern Ocean around the Antarctic continent and on most sub-Antarctic islands. The New Zealand population is concentrated on the Antipodes Islands and on Campbell Island. In winter, they frequently visit the Auckland, Antipodes and Snares Islands, less often the Chatham Islands and occasionally various mainland locations, from Stewart Island to the Bay of Islands.

Southern elephant seals haul-out on sand or gravel beaches with easy access as large males in particular find movement on land challenging.

When visiting local coastlines to moult, young elephant seals may stay in an area for months, giving people an opportunity to observe these animals. They can be an impressive sight, and young seals can be very playful. Enjoy their visits, but remember they are wild animals, and should be respected as such.

Population

There has been a long-term, annual decline of 5-11% of elephant seals at most colonies in the southern oceans. The reason for this is unknown, the two major theories being:

• decline is related to commercial exploitation of prey stocks; and
• the population is returning to pre-sealing levels after having recovered to abnormally high levels.

The total population was estimated at 607,000 in 1990 compared to 768,000 in 1985.

The New Zealand breeding stock is small; the Campbell Island population was numbered at 417 in the late 1940s and has since declined by 97%.

Diet and foraging

Elephant seals feed on animals such as squid, cuttlefish and large fish, including sharks.

Elephant seals are deep-sea feeders. At sea, they spend about 90% of their time underwater. Most dives are to depths of between 300 and 800 m and last 20-27 minutes. Surface intervals between dives are much shorter at only 2-4 minutes.

Dives during the day tend to be much deeper than at night. Their high blood volume and oxygen capacity suggests they are capable of deep diving. Elephant seals are not particularly agile even in the water but can swim at speeds up to 20-25 km/h.

Breeding

Breeding males arrive at rookeries in August, and pregnant females arrive in September and October. Males do not maintain territories but do establish dominance hierarchies structured primarily by age, secondarily by size, and to some extent, by previous experience. Males threaten each other visually and vocally.

Males are sexually mature at 3-6 years, but few breed before they are 10 years old. Only the largest two or three males breed in a given year. Many males will never breed with 90% dying before reaching sexual maturity. Females are sexually mature at 2-4 years old and may then give birth annually for 12 years. Breeding males may mate with 100 females in a season.

Females give birth to a single pup shortly after coming ashore in September or October and will then remain ashore for the next 23 or so days nursing her pup. A few weeks later the females mate and then depart, abruptly weaning their pups. Females then remain at sea feeding for 70 days before coming ashore to moult. Pups remain ashore for a period of 50 days before finally going to sea to feed.

Behaviour

Seals normally come ashore to rest after long periods at sea or sometimes when they are sick, injured or tangled up in debris or nets. Young elephant seals come ashore to moult in summer. During moulting, they normally don't feed, rarely go back to the sea, and can stay in one location for several months. Moulting usually takes place in the tussock above beaches where they wriggle around in dry sand to slough off old skin.

Adult females moult slightly later in the season followed by the males in the autumn to winter months. Adult moulting takes place in deep, muddy wallows, shared with many others.

Threats

Predators

Leopard seals occasionally attack and kill pups, and killer whales may prey on pups and older seals, though neither are believed to have any significant affect on the population.

Human impact

Southern elephant seals were harvested for oil in the early 1800s after Antarctic fur seal numbers dropped. Numbers reduced dramatically and by 1900 sealing was no longer economically profitable. After a short period of recovery sealing was resumed but following management regulations from 1909 to 1964 when it was found to be no longer viable. Approximately 260,000 bull elephant seals were harvested from 1910 - 1965.

The southern elephant seal is now fairly widespread and recovering in numbers following huge hunting pressure in the nineteenth century.

Today, the main threat to elephant seals in New Zealand is harassment by humans or dogs while ashore. Seals usually haul out on land to rest, moult or breed and at these times they should be left undisturbed. It is also possible that elephant seals are affected by ship-strike and fishing mortality though little information exists on these impacts.

IUCN Red List of Threatened Species status: Least Concern (population trend: unknown).

DOC's work

Elephant seals are protected under the Wildlife Act 1953 and the Marine Mammal Protection Act 1978.

DOC is currently creating a database to record sightings of elephant seals. This is to help work out the present distribution and range of the species.

We're also working with researchers from other countries to gather information on the number of seal pups produced each year and to work out what elephant seals eat in the New Zealand Sub-Antarctic Islands.

Elephant seals are very large animals. They could easily crush a person simply by rolling over and can move surprisingly quickly on land. Although they have fairly small teeth, they are capable of penetrating another seal's skin and can inflict a serious wound to humans.

Report sightings of seals and sea lions

We are particularly interested in sightings of seals or sea lions which are rarely seen in New Zealand. See New Zealand fur seals for information on when to call us for that species.

You can report sightings of seals to our conservation hotline 0800 DOC HOT (0800 362 468). You can also report a sighting online.

Reports of sightings are always valuable and help increase our knowledge of seal and sea lion distribution and movements around New Zealand.

If you need help identifying species, download the marine mammal sighting form (PDF, 416K) (Word, 4,300K). You can use the images and descriptions to find out which species of seal or sea lion you observed.

Record the details

Include as much information as possible with your sighting:

• the date, time and location (GPS coordinates if possible)
• the number of seals and estimated sizes
• take photographs or video 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. Adult seals can move surprisingly quickly on land. While they can look harmless, seals can inflict serious injuries to dogs or people and 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.