Healthy diets

What Is a Seal’s Favorite Food?

María Luz Thurman
By María Luz Thurman, Biologist/ornithologist. Updated: July 16, 2024
What Is a Seal’s Favorite Food?

Seals are an incredibly diverse and fascinating group of marine mammals, comprising over 30 different species found worldwide. Seals play a vital role in maintaining the delicate balance of marine ecosystems. As apex predators, they help to regulate prey populations, preventing the overexploitation of certain species and ensuring that the ecosystem remains healthy.

The following AnimalWised article provides a comprehensive overview of seal diets, hunting behaviors, and the impact of human activities on seal populations.

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  1. What do seals eat?
  2. How do seals hunt?
  3. What do baby seals eat?
  4. Human impact on seal diets

What do seals eat?

Seals, classified as obligate carnivores, exclusively consume meat in their diet.

The composition of their diet varies according to the species and geographic location, with fish serving as the primary staple for most seals. Fish are abundant and serve as a rich source of protein, fat, and essential vitamins and minerals.

The specific species of fish consumed by seals exhibit variability contingent on geographic location, prey availability, and species-specific preferences. For instance, larger seals, exemplified by Mirounga angustirostris (elephant seals) and Leptonychotes weddellii (Weddell seals), demonstrate the ability to dive to considerable depths to secure their fish prey. Conversely, smaller seals, including Phoca vitulina (harbor seals) and Arctocephalus spp. (fur seals), predominantly engage in hunting near the water's surface.

Certain seal species, such as Cystophora cristata (hooded seals) and Hydrurga leptonyx (leopard seals), exhibit a dietary preference for squid and octopus. These cephalopods, known for their high protein and fat content, constitute valuable additions to the seal diet. Squid, specifically, holds particular significance for seals inhabiting the Southern Ocean.

In addition to fish and cephalopods, seals may also include Crustacea and Mollusca in their diet. Crustaceans, encompassing species like shrimp, krill, and crabs, along with mollusks such as clams, oysters, and scallops, occasionally contribute to the diverse seal diet. These invertebrates offer essential nutrients, including calcium and zinc, crucial for maintaining optimal seal health.

What do seals eat?

Yes, seals eat every day. The frequency and quantity of their meals vary depending on the species, size, and activity level of the seal.

Larger seals, such as elephant seals and Weddell seals, can consume up to 10% of their body weight in food per day. They eat several times a day, taking breaks between dives to rest and digest their food.

Smaller seals, such as harbor seals and fur seals, eat less often, but they still need to eat enough to fuel their daily activities. They typically eat 1-2 times per day, consuming up to 5% of their body weight in food per meal.

How do seals hunt?

Seals are skilled predators that employ a variety of techniques to catch their prey, depending on the species and their environment. Here are some of the most common hunting methods used by seals:

Surface hunting

Some seals, such as elephant seals (Mirounga angustirostris) and weddell seals (Leptonychotes weddellii), are adept at chasing down fish near the water's surface. They use their keen eyesight to spot prey, and their powerful muscles to lunge and snatch fish with their conical, sharp teeth.

Furthermore, harbor seals (Phoca vitulina) often employ a unique strategy of basking on the water's surface to absorb the sun's warmth. This seemingly passive behavior allows them to ambush fish that venture too close.

Bubble-net hunting

Harp seals (Pagophilus groenlandicus) and bearded seals (Erignathus barbatus) are known for their bubble-net hunting technique. They form a circular curtain of bubbles around a school of fish, disorienting and trapping them. With a sudden burst of energy, they break through the bubble net, stunning or killing the entrapped fish.

Deep-sea hunting

Larger seals, such as elephant seals (Mirounga angustirostris) are capable of diving to extreme depths to capture prey. They use their sensitive whiskers and echolocation to navigate the murky depths and locate fish. Their large mouths and powerful jaws allow them to capture prey that other predators cannot reach.

Tool use and problem-solving

Elephant seals have been observed using their flippers to break open ice floes, exposing crustaceans and fish that they would otherwise not be able to reach. On the other hand, harbor seals have been observed using kelp fronds to camouflage themselves while hunting, making it easier to ambush unsuspecting prey.

Want to know more about the fascinating differences between seals, sea lions, and walruses? Explore our other article to uncover these distinctions.

What do baby seals eat?

Baby seals, also known as pups, feed primarily of milk from their mothers, which provides them with essential nutrients for growth and development. Pups nurse for several weeks or months, gradually transitioning to solid food as they mature.

Seal milk is highly nutritious and packed with essential nutrients that are vital for the growth and development of baby seals. It is a rich source of fat, protein, vitamins, and minerals, including vitamin A, vitamin D, vitamin E, calcium, and phosphorus. The fat content of seal milk is particularly high, ranging from 40% to 50%, which provides pups with the energy they need to grow rapidly.

The high fat content of seal milk makes it a very energy-dense food. Pups can consume up to 20% of their body weight in milk per day, which is essential for their rapid growth. The high nutrient content of seal milk also supports the development of their immune system and brain. The size of the pup's mother can influence the amount of milk she produces and the frequency of nursing. Larger mothers typically produce more milk and nurse their pups more often.

Baby seals learn to hunt by observing their mothers and practicing their hunting skills. They start by scavenging for leftover food from their mothers and gradually learn to catch their own prey. As they mature, they become more skilled hunters and are able to capture a wider variety of prey. The availability of prey can also affect baby seal diets. When prey is abundant, pups may nurse less frequently and spend more time foraging for food themselves.

What Is a Seal’s Favorite Food? - What do baby seals eat?

Human impact on seal diets

Human activities, such as commercial fishing, recreational fishing, and habitat destruction, have contributed to the decline of several fish populations that serve as prey for seals. Overfishing, in particular, has led to the depletion of many fish stocks, making it more difficult for seals to find their food. This can have a significant impact on seal populations, as they may not be able to obtain the nutrients they need to survive.

The decline of prey species has forced seals to adapt their hunting strategies and dietary habits. They may switch to different prey species, travel longer distances to find food, or even change their feeding times. In some cases, seal populations may decline due to the loss of their prey base.

Pollutants, such as heavy metals and persistent organic pollutants (POPs), can enter the marine food chain and accumulate in the bodies of seals. These pollutants can have a variety of negative effects on seal health, including reproductive problems, immune system dysfunction, and cancer.

Seals that consume contaminated prey can become sick or even die. They may also pass the pollutants on to their offspring through their milk, which can further impact seal populations. In addition, contaminated prey can make it difficult for seals to obtain the nutrients they need, which can further weaken their health.

Overall, human activities are having a significant impact on seal diets and health. Overfishing is depleting prey populations, while pollution is contaminating seals' food and causing widespread health problems. These threats are putting immense pressure on seal populations and could have severe consequences for the future of these marine mammals.

If you want to read similar articles to What Is a Seal’s Favorite Food?, we recommend you visit our Healthy diets category.

  • Hammill, M. O. (2009). Earless seals: Phocidae . In Encyclopedia of marine mammals (pp. 342-348). academic press
  • Mar, MGR (2016). Determination of the lactation period and maternal care in the harbor seal Phoca vitulina richardii and its relationship with human disturbance in the Punta Banda estuary, Baja California, Mexico .
  • Márquez, ME, Carlini, AR, Baroni, AV, & Ronayne de Ferrer, PA (2008). Variations in fat and protein levels in the milk of the Weddell seal (Leptonychotes weddellii Lesson, 1826) on Laurie Island, Antarctica: preliminary study. Journal of Marine Biology and Oceanography, 43(1), 153-158.
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What Is a Seal’s Favorite Food?