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What the sources say

Weddell SealLeptonychotes weddellii

Every figure, record and mechanism on the Weddell Seal profile was written from a source, and this is the working table behind it: 38 claims checked word for word against these sources. The left column is what the page says. The right column is the source's own words, copied, not paraphrased; a ... marks a cut and[brackets] an insertion. Open any source and check it yourself.

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Source
01

Australian Antarctic Program 2018

Weddell seal. Australian Antarctic Program, 2018.

The page saysThe most southerly-ranging mammal living permanently in Antarctica
The source saysWeddell seals are the most southerly ranging mammal to permanently inhabit the continent.Note: tagline; scope kept to the source's 'permanently inhabit the continent'
The page saysrasping breathing holes through new sea ice with its teeth
The source saysWeddell seals use their canine and incisor teeth to rasp open the new ice and so maintain holes through which to breathe.Note: tagline
The page saysdiving as deep as 720 metres
The source saysremaining under water for up to 45 minutes and reaching depths as great as 720 m in search of preyNote: tagline
The page saysRasps breathing holes open through new sea ice with its canine and incisor teeth
The source saysWeddell seals use their canine and incisor teeth to rasp open the new ice and so maintain holes through which to breathe.Note: stats.superpower
The page saysdives as deep as 720 metres
The source saysremaining under water for up to 45 minutes and reaching depths as great as 720 m in search of preyNote: stats.superpower
The page saysMid-water and bottom-dwelling fish, squid, octopus and prawns
The source saysmid-water (pelagic) and bottom dwelling (benthic) fish, squid, octopus and prawns are commonNote: stats.diet
The page saysFast ice and inshore coastal waters around the continental coast of Antarctica
The source saysWeddell seals have a circumpolar distribution and are coastal, staying around the fast iceNote: stats.habitat
The page saysOf all the mammals that live permanently in Antarctica, none ranges further south than the Weddell seal
The source saysWeddell seals are the most southerly ranging mammal to permanently inhabit the continent.Note: body, section 1
The page sayswhich lives on and around the fast ice all the way round the continent's coast
The source saysWeddell seals have a circumpolar distribution and are coastal, staying around the fast iceNote: body, section 1; 'all the way round' = circumpolar
The page saysAdults of both sexes are about 3 metres long and weigh around 400 to 500 kg
The source saysBoth adult males and females are about 3 metres long and weigh around 400-500 kg.Note: body, section 1; ADW (2000) sex-specific lengths dropped, AAP (2018) is the current institution page
The page saysventuring only 15 to 20 km into the Southern Ocean to feed
The source saysventuring only 15-20 km into the Southern Ocean to feedNote: body, section 1
The page saysreturn to the same area of fast ice each year to rest, moult and give birth
The source saysWeddell seals haul-out onto the stable fast-ice to rest and moult, and for females to pup, returning to the same area each year.Note: body, section 1
The page saysIn the warmer summer months the ice has many cracks to breathe through. In winter those openings freeze over
The source saysThere are many cracks in the ice during the warmer summer months. During winter these openings freeze overNote: body, section 2
The page saysusing their canines and incisors to rasp open the new ice and maintain a breathing hole
The source saysWeddell seals use their canine and incisor teeth to rasp open the new ice and so maintain holes through which to breathe.Note: body, section 2
The page saysthe constant grinding wears those teeth down, and enough wear may eventually leave a seal unable to feed or keep its holes open
The source saysMaintaining these breathing holes results in teeth wearing down to such an extent that the animal may eventually be unable to feed or keep the precious holes open.Note: body, section 2
The page saysHunting dives can last up to 45 minutes and reach depths as great as 720 metres
The source saysremaining under water for up to 45 minutes and reaching depths as great as 720 m in search of preyNote: body, section 3
The page saysa diet of pelagic and bottom-dwelling fish, squid, octopus and prawns; one seal was repeatedly observed to capture a fish weighing more than 40 kg
The source saysmid-water (pelagic) and bottom dwelling (benthic) fish, squid, octopus and prawns are common. One seal was repeatedly observed to capture a fish weighing more than 40 kg.Note: body, section 3
The page saysthe space beneath it is relatively safe from air-breathing predators such as killer whales and leopard seals
The source saysThe under-ice environment is relatively safe from air breathing predators such as killer whales and leopard sealsNote: body, section 3
The page saysRecorded Weddell seal calls include repeated chirps, a long high whistle falling in tone, or a single, slowly descending tone
The source saysThis call is a long high whistle, falling in tone. ... This call consists of repeated chirps. ... This call is a single, slowly descending tone.Note: body, section 4; three AAP underwater-call audio captions
The page saysBoth sexes call, and males may do so to hold their underwater territories
The source saysBoth male and female seals vocalise, males may do so to maintain established territories.Note: body, section 4
The page saysFemales aged six and over give birth to one pup a year, in October
The source saysFemales of 6 years and over give birth in October to 1 pup per year.Note: body, section 4
The page saysA newborn weighs 25 to 30 kg; after six weeks of its mother's care it has grown to 110 to 140 kg
The source saysPups weigh 25-30 kg at birth and mothers care for them for 6 weeks by which time they have grown to 110-140 kg.Note: body, section 4
The page saysIt makes its own. Working at the freshly frozen surface with its canine and incisor teeth, a seal rasps a breathing hole open and keeps it that way
The source saysDuring winter these openings freeze over and Weddell seals use their canine and incisor teeth to rasp open the new ice and so maintain holes through which to breathe.Note: FAQ 1
The page saysit has to find those holes again in the darkness of winter before its oxygen runs out
The source saysA seal must find its way to the breathing holes before it runs out of oxygen. Their powers of navigation must be highly accurate as they must find these holes even during the darkness of winter.Note: FAQ 1
The page saysworn-down teeth may eventually leave a seal unable to feed or hold its holes open
The source saysMaintaining these breathing holes results in teeth wearing down to such an extent that the animal may eventually be unable to feed or keep the precious holes open.Note: FAQ 1
The page saysThe fast ice is where they haul out to rest, moult and give birth
The source saysWeddell seals haul-out onto the fast-ice to rest and moult, and for females to pup.Note: FAQ 3
The page saysthe water beneath it is relatively safe from air-breathing predators such as killer whales and leopard seals
The source saysThe under-ice environment is relatively safe from air breathing predators such as killer whales and leopard sealsNote: FAQ 3
The page saysUnderwater they usually keep within 50 to 100 km of their breeding colony, though some, especially juveniles, make occasional journeys of several hundred kilometres
The source saysUnderwater they remain relatively close to their breeding colonies, usually within 50-100 km though occasional migrations of several hundred kilometres do occur, especially by juveniles.Note: FAQ 3
The page saysUnder the fast ice, Weddell seals call to each other in long whistles falling in tone, strings of repeated chirps and single, slowly descending tones.
The source saysThis call is a long high whistle, falling in tone. Weddell seal underwater call 2 This call consists of repeated chirps. Weddell seal underwater call 3 This call is a single, slowly descending tone.

Source
02

National Geographic

Weddell Seal. National Geographic.

The page saysNational Geographic gives the species' average life span in the wild as 30 years
The source saysAverage Life Span In The Wild : 30 yearsNote: body, section 4; reference work, basic fact only, attributed
The page saysNational Geographic lists the Weddell seal's average life span in the wild as 30 years
The source saysAverage Life Span In The Wild : 30 yearsNote: FAQ 4

Source
03

Williams et al. 2007

Williams et al. (2007). Running, swimming and diving modifies neuroprotecting globins in the mammalian brain. Proceedings of the Royal Society B: Biological Sciences.

The page sayscan stay under for more than 90 minutes with no neurological or behavioural impairment
The source saysWeddell seals (Leptonychotes weddellii), which can remain underwater for more than 90 min while exhibiting no neurological or behavioural impairment.Note: stats.superpower
The page saysA Weddell seal can stay underwater for more than 90 minutes with no neurological or behavioural impairment
The source saysWeddell seals (Leptonychotes weddellii), which can remain underwater for more than 90 min while exhibiting no neurological or behavioural impairment.Note: blockquote; background statement in the abstract of a brain-globin study, not a result of it, so no study is credited
The page sayseven though its blood oxygen falls to levels that would leave a human unconscious
The source saysThis response occurs despite exposure to blood oxygen levels concomitant with human unconsciousness.Note: blockquote; the human comparison is the paper's own
The page saysA human brain can be injured after just a few minutes of oxygen deprivation underwater
The source saysThe vulnerability of the human brain to injury following just a few minutes of oxygen deprivation with submergenceNote: FAQ 2
The page saysa study measuring oxygen-carrying proteins in the cerebral cortex of 16 mammal species found a nearly 9.5-fold range in haemoglobin between land mammals and deep divers
The source sayswe measured the presence of circulating (haemoglobin) and resident (neuroglobin and cytoglobin) oxygen-carrying globins in the cerebral cortex of 16 mammalian species considered terrestrial, swimming or diving specialists. Here we report a striking difference in globin levels depending on activity lifestyle. A nearly 9.5-fold range in haemoglobin concentration (0.17-1.62 g Hb 100 g brain wet wt(-1)) occurred between terrestrial and deep-diving mammalsNote: FAQ 2; the abstract does not say whether Weddell seals were among the 16, hence 'may lie' and 'deep divers'
The page saysThe authors conclude these proteins help move oxygen into nerve tissue, letting marine mammals keep sensory and locomotor functions working during prolonged submergence
The source saysTogether, these two globin groups provide complementary mechanisms for facilitating oxygen transfer into neural tissues and the potential for protection against reactive oxygen and nitrogen groups. This enables marine mammals to maintain sensory and locomotor neural functions during prolonged submergenceNote: FAQ 2

Source
04

Hückstädt 2026

Hückstädt (2026). Leptonychotes weddellii. The IUCN Red List of Threatened Species 2026: e.T11696A95969474.

The page saysLeast Concern
The source saysIUCN Red List category: Least Concern (LC).Note: stats.conservationStatus; GBIF's copy of the Red List

How the table was made: a writer drafted the profile from these sources and logged each claim with its quote, a reviewer with nothing but this table checked every sentence said no more than its quote, and a script confirmed each quote appears word for word in the source. The method is in the site'sAbout page.