---
title: "What the sources say about the Harbor Seal | AnimalTracks.wiki"
description: "40 claims from the Harbor Seal profile, each beside the words of the source that backs it."
image: "https://animaltracks.wiki/images/animals/harbor-seal-1.webp"
canonical: "https://animaltracks.wiki/animals/harbor-seal/sources/"
---

# What the sources say about the Harbor Seal (*Phoca vitulina*)

> 40 claims from the Harbor Seal profile, each beside the words of the source that backs it. A "..." marks a cut in a quote and [brackets] an insertion.

Profile: [Harbor Seal](https://animaltracks.wiki/animals/harbor-seal/)

## Harbor Seal. NOAA Fisheries.

https://www.fisheries.noaa.gov/species/harbor-seal

| The page says | The source says |
| :--- | :--- |
| along the northern coasts of North America, Europe and Asia | Harbor seals live in temperate coastal habitats along the northern coasts of North America, Europe, and Asia |
| hauling out on rocks, beaches and drifting glacial ice | Harbor seals haul out (rest) on rocks, reefs, beaches, and drifting glacial ice (note: reefs dropped from the source's list) |
| in North America from Baja California to the Bering Sea and from the Canadian Arctic to the Mid-Atlantic | harbor seals are found from the Canadian Arctic to the Mid-Atlantic ... all along the West Coast of North America, from Baja California, Mexico to the Bering Sea (note: quote spans two sentences of the same paragraph; NOAA gives the Atlantic-coast range first, then the Pacific-coast range) |
| The harbor seal (Phoca vitulina) is a true seal. | Harbor seals are part of the true seal family. |
| It has no external ear flaps, just a small hole on each side of its head | They also lack external ear flaps and instead have a small hole (opening to the ear canal) on either side of their head. |
| its pelvic bones are fused, so it can't tuck its hind flippers under its body to walk the way a sea lion does. On land it gets around by undulating like a caterpillar instead | Harbor seal pelvic bones are fused, preventing them from moving their hind flippers under their pelvis to walk on land like sea lions. Instead, they move by undulating in a caterpillar-like motion. (note: 'so' paraphrases the source's own 'preventing') |
| A harbor seal weighs up to 285 pounds and measures up to 6 feet long | Harbor seals weigh up to 285 pounds and measure up to 6 feet in length. (note: NOAA's page (last updated 03/25/2026) replaces the Smithsonian's 120-300 lb male range, which it contradicts) |
| males are slightly larger than females, and seals in Alaska and the Pacific are generally larger than those in the Atlantic | Males are slightly larger than females, and seals in Alaska and the Pacific Ocean are generally larger than those found in the Atlantic Ocean. |
| along North America's west coast from Baja California to the Bering Sea, its east coast from the Canadian Arctic to the Mid-Atlantic, and the northern coasts of Europe and Asia | Harbor seals live in temperate coastal habitats along the northern coasts of North America, Europe, and Asia ... On the eastern North America Coast, harbor seals are found from the Canadian Arctic to the Mid-Atlantic. Harbor seals are found all along the West Coast of North America, from Baja California, Mexico to the Bering Sea. |
| It's ready to swim within minutes of birth, can dive for up to 2 minutes by the time it's 2 or 3 days old, and by the end of its first month may set off on journeys of more than 100 miles from its birth site | Harbor seal pups can swim at birth. They can also dive for up to 2 minutes when they are only 2 to 3 days old and by the end of their first month of life embark on journeys of over 100 miles from their natal area. ... Pups weigh about 24 pounds at birth and are ready to swim within minutes. |
| It nurses for 4 to 6 weeks on milk that's 50 percent fat | They nurse for 4 to 6 weeks on milk that is 50 percent fat. |
| seals that haul out in groups spend less time watching for predators than those that haul out alone | These seals also haul out in groups to avoid predators and spend less time being watchful for predators than those that haul out alone. |
| Yes. Harbor seal pups can swim at birth. By 2 to 3 days old they can dive for up to 2 minutes, and by the end of their first month they may set off on journeys of more than 100 miles from where they were born. They nurse for 4 to 6 weeks on milk that's 50 percent fat | Harbor seal pups can swim at birth. They can also dive for up to 2 minutes when they are only 2 to 3 days old and by the end of their first month of life embark on journeys of over 100 miles from their natal area. ... They nurse for 4 to 6 weeks on milk that is 50 percent fat. |

## Harbor seal. Smithsonian's National Zoo and Conservation Biology Institute.

https://nationalzoo.si.edu/animals/harbor-seal

| The page says | The source says |
| :--- | :--- |
| a diver whose heart can slow to three or four beats a minute | Before a deep dive, harbor seals exhale to reduce the amount of oxygen in their lungs, relying instead on stored oxygen in their blood and muscle tissues. ... Harbor seals also slow their heart rates from upwards of 80-120 beats per minute to as few as three or four. (note: vibe.reason, settled after the wave: the heart-rate sentence sits in the Smithsonian's diving paragraph) |
| a heart rate that can drop to three or four beats a minute on a dive | Like other pinnipeds, harbor seals are adapted to dive and conserve oxygen underwater. ... harbor seals also slow their heart rates from upwards of 80-120 beats per minute to as few as three or four (note: the heart-rate sentence sits in the Smithsonian's paragraph on diving, after 'Before a deep dive') |
| the widest range of any seal on Earth | They have the widest distribution of any seal |
| Rockfish, herring, cod, mackerel, flounder and salmon, plus squid, octopus, crabs and shrimp | primarily eat fish, such as rockfish, herring, cod, mackerel, flounder and salmon. They also eat squid, clams, octopus, crayfish, crabs and shrimp when available. (note: clams and crayfish dropped from the stats field's list for brevity; all listed items are verbatim from the source) |
| It has the widest range of any seal | They have the widest distribution of any seal |
| A wild harbor seal can live 25 to 30 years, and more than 30 in human care | Harbor seals in the wild can live between 25 and 30 years and for more than 30 years in human care. (note: NOAA's 2026 page agrees (Lifespan About 25 to 30 years); ADW's 2012 account (average 40 years wild) is overruled) |
| A harbor seal eats mainly fish, such as rockfish, herring, cod, mackerel, flounder and salmon, plus squid, octopus, crabs and shrimp when available | primarily eat fish, such as rockfish, herring, cod, mackerel, flounder and salmon. They also eat squid, clams, octopus, crayfish, crabs and shrimp when available. (note: clams and crayfish dropped from the source's list) |
| Before a deep dive, a harbor seal exhales to cut the oxygen in its lungs and relies on oxygen stored in its blood and muscle instead | Before a deep dive, harbor seals exhale to reduce the amount of oxygen in their lungs, relying instead on stored oxygen in their blood and muscle tissues. |
| Blood is shunted away from its extremities toward its brain, heart and lungs, and its heart rate slows from upwards of 80 to 120 beats a minute to as few as three or four | Blood is shunted away from the extremities and concentrated on maintaining the core functions of the brain, heart and lungs where it is needed. Harbor seals also slow their heart rates from upwards of 80-120 beats per minute to as few as three or four. |
| It can stay under for up to 30 minutes, though the average dive lasts under three | They can remain submerged for up to 30 minutes at a time, but the average dive lasts less than three minutes |
| It can generally dive to about 500 feet, but dives as deep as 1,460 feet have been recorded | They can generally dive to depths of about 500 feet (152 meters), but dives up to 1,460 feet (446 meters) have been recorded. (note: ADW's 2012 maximum of 427 m is older and smaller; the Smithsonian's recorded 446 m stands) |
| Its body burns energy faster than other mammals its size, which generates heat to keep it warm, and in winter its insulating blubber can make up as much as 30 percent of its body mass | These seals have a higher metabolic rate than other mammals of comparable size, which allows them to generate heat to keep warm ... A thick layer of insulating blubber provides thermoregulation and a nutrient reserve for fasting periods. During the winter, the blubber layer can account for up to 30 percent of a harbor seal's body mass. (note: 'burns energy faster' renders 'higher metabolic rate' for readers aged 11 to 14) |
| Harbor seals stay alert for predators such as polar bears, orcas and sharks | Harbor seals spend the majority of their time staying alert for predators, such as polar bears, orcas and sharks. |
| A seal that senses danger gives an alarm call and usually dives for the water | it will let out an alarm call and flee, usually by diving into the water, if it senses danger |
| Before a deep dive it exhales to cut the oxygen in its lungs, relying instead on oxygen stored in its blood and muscle. Blood is shunted away from its extremities toward its brain, heart and lungs, and its heart rate slows from upwards of 80 to 120 beats a minute to as few as three or four, then speeds up rapidly for a short time after it surfaces. It can stay down for up to 30 minutes, though the average dive lasts under three | They can remain submerged for up to 30 minutes at a time, but the average dive lasts less than three minutes ... Before a deep dive, harbor seals exhale to reduce the amount of oxygen in their lungs, relying instead on stored oxygen in their blood and muscle tissues. Blood is shunted away from the extremities and concentrated on maintaining the core functions of the brain, heart and lungs where it is needed. Harbor seals also slow their heart rates from upwards of 80-120 beats per minute to as few as three or four. After surfacing, the seal's heartbeat accelerates rapidly for a short period of time. |
| Yes. Harbor seals have the widest distribution of any seal, living in both the North Atlantic and North Pacific oceans, from cool temperate waters up into cold Arctic and sub-Arctic coasts | They have the widest distribution of any seal and live in both the North Atlantic and Northern Pacific oceans, ranging from cool, temperate waters to cold, arctic and sub-arctic coasts. |

## Phoca vitulina (harbor seal). Animal Diversity Web, University of Michigan.

https://animaldiversity.org/accounts/Phoca_vitulina/

| The page says | The source says |
| :--- | :--- |
| Coastal bays and estuaries | Harbor seals populate the shallow waters of coastal areas, bays, rocky islets, estuaries, and even freshwater lakes. |
| aiming to keep its foraging effort low by eating what is abundant and easily caught | the overarching goal of harbor seals is to keep foraging efforts low by eating what is abundant and easily caught |
| A harbor seal pup sheds its downy lanugo coat well before birth and is born with fur the same texture as an adult's, which lets it safely enter cooler water | a fine, downy coat of hair called lanugo after birth, harbor seal pups shed their lanugo well before they are born. At birth, the pups' fur is the same texture as that of the adults, which allows them to safely enter cooler waters. (note: 'which lets' paraphrases the source's 'which allows') |

## Dehnhardt et al. (2001). Hydrodynamic Trail-Following in Harbor Seals ( Phoca vitulina ). Science.

https://doi.org/10.1126/science.1060514

| The page says | The source says |
| :--- | :--- |
| Whiskers that detect a swimming fish's wake | fish-generated water movements, which seals can detect with their highly sensitive whiskers. Water movements in the wake of fishes persist for several minutes. |
| Highly sensitive whiskers that detect the water movements a swimming fish leaves behind; blindfolded seals can use them to accurately follow a hydrodynamic trail | fish-generated water movements, which seals can detect with their highly sensitive whiskers. ... blindfolded seals can use their whiskers to detect and accurately follow hydrodynamic trails generated by a miniature submarine (note: the trail the blindfolded seals followed was a miniature submarine's, so the page does not say they followed a fish's) |
| In dark or murky water, dolphins hunt using echolocation | Marine mammals often forage in dark or turbid waters. Whereas dolphins use echolocation under such conditions (note: final pass: 'often' belongs to marine mammals foraging in dark water, not to dolphins, so it is dropped) |
| Seals apparently don't have that sense | pinnipeds apparently lack this sensory ability (note: paraphrase of 'lack this sensory ability' as 'don't have that sense'; 'Seals' narrows the abstract's 'pinnipeds', a term the page never defines) |
| a seal's highly sensitive whiskers can detect the water movements a fish makes, and those movements persist in its wake for several minutes | fish-generated water movements, which seals can detect with their highly sensitive whiskers. Water movements in the wake of fishes persist for several minutes. |
| Researchers once blindfolded harbor seals and had them track the wake of a miniature submarine with their whiskers; the seals followed it accurately, showing that water movements like these can be used to locate prey at long distance | blindfolded seals can use their whiskers to detect and accurately follow hydrodynamic trails generated by a miniature submarine. This shows that hydrodynamic information can be used for long-distance prey location. (note: the paper's title names the species: Hydrodynamic Trail-Following in Harbor Seals (Phoca vitulina); 'water movements like these' renders 'hydrodynamic information' for readers aged 11 to 14) |
| Seals apparently lack the echolocation dolphins use in dark or murky water. Instead, a harbor seal's highly sensitive whiskers can detect the water movements a swimming fish makes, which persist in its wake for several minutes. In one study, blindfolded seals used their whiskers to detect and accurately follow the wake of a miniature submarine, showing that water movements like these can be used to locate prey at long distance | Marine mammals often forage in dark or turbid waters. Whereas dolphins use echolocation under such conditions, pinnipeds apparently lack this sensory ability. For seals hunting in the dark, one source of sensory information may consist of fish-generated water movements, which seals can detect with their highly sensitive whiskers. Water movements in the wake of fishes persist for several minutes. Here we show that blindfolded seals can use their whiskers to detect and accurately follow hydrodynamic trails generated by a miniature submarine. This shows that hydrodynamic information can be used for long-distance prey location. (note: 'Seals' narrows the abstract's 'pinnipeds') |

## Russell (2025). Phoca vitulina. The IUCN Red List of Threatened Species 2025: e.T17013A225215605.

https://doi.org/10.2305/iucn.uk.2025-1.rlts.t17013a225215605.en

| The page says | The source says |
| :--- | :--- |
| The IUCN lists the harbor seal as Least Concern | IUCN Red List category: Least Concern (LC). |