Marine predator reference

Ocean predators, measured side by side.

How long is a colossal squid next to a sperm whale? Which hunts deeper, and which is closer to extinction? Put any two ocean predators together and compare them against sourced measurements rather than guesswork.

Start a comparison Browse all predators
33 Species profiles
15 Written comparisons
18 Traits compared
Adult orca surfacing in cold coastal water, showing its glossy black back, tall triangular dorsal fin, white oval eye patch and gray saddle. Orca Orcinus orca

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The catalog

Seven kinds of ocean hunter

Predators reach the top of a marine food web along very different routes. These groups are organized by how each animal is built and how it makes a living, not by how dangerous it is.

8 profiles

Sharks

Cartilaginous hunters ranging from coastal reef patrollers to slow-moving polar giants.

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Blue shark in open ocean, showing its slim indigo-blue back, white belly, long pointed snout and unusually long, narrow pectoral fins. Blue Shark Bull shark in shallow green water, showing its stocky gray body, short blunt snout, small eyes and tall triangular first dorsal fin. Bull Shark Great hammerhead shark seen from above, showing the wide flat cephalofoil with eyes at the tips and a very tall, curved first dorsal fin. Great Hammerhead Shark
5 profiles

Toothed Whales & Dolphins

Air-breathing mammals that hunt with echolocation, often in cooperative family groups.

See all toothed whales & dolphins
Common bottlenose dolphin leaping clear of the water, gray above and pale below, with a short thick beak, creased jawline and tall curved dorsal fin. Common Bottlenose Dolphin False killer whale swimming near the surface, slender and uniformly dark gray with a rounded beakless head, tall curved dorsal fin and bent narrow flippers. False Killer Whale Adult orca surfacing in cold coastal water, showing its glossy black back, tall triangular dorsal fin, white oval eye patch and gray saddle. Orca
5 profiles

Seals, Sea Lions & Walruses

Amphibious mammals that feed at sea and return to shore or ice to rest and breed.

See all seals, sea lions & walruses
A California sea lion gliding through sunlit blue-green water above a kelp bed, its long foreflippers spread and its whiskers and large dark eyes clearly visible. California Sea Lion A leopard seal turning through cold blue Antarctic water beneath a pale ice floe, its long spotted body and wide head angled toward the camera with the mouth slightly open. Leopard Seal An enormous southern elephant seal bull on a grey sub-Antarctic beach, head raised and inflated proboscis hanging over its open mouth, with scarred folds of skin across its chest. Southern Elephant Seal
2 profiles

Marine Crocodilians

Ambush reptiles that cross saltwater and dominate estuaries, mangroves and river mouths.

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American crocodile resting on a mangrove bank, showing a narrow tapered snout, olive-gray scales, and a raised bony ridge just in front of the eyes. American Crocodile Saltwater crocodile floating at the surface of a muddy estuary, showing a broad heavy snout, raised eyes and nostrils, and rows of dark scutes along its back. Saltwater Crocodile
4 profiles

Predatory Cephalopods

Soft-bodied molluscs with arms, tentacles and beaks, from reef octopuses to deep-sea squid.

See all predatory cephalopods
Colossal squid in dark water, showing a stout pale mantle, short thick arms, an enormous dark eye, and hooked clubs at the ends of two tentacles. Colossal Squid Giant Pacific octopus on a rocky reef with mottled red-brown skin, raised papillae, and long arms lined with two rows of pale suckers. Giant Pacific Octopus Giant squid in dark water showing a tapered reddish mantle, triangular fins, eight arms and two much longer feeding tentacles ending in clubbed tips. Giant Squid
6 profiles

Predatory Fish

Bony fish built for speed, ambush or venom, including billfish, tuna and reef hunters.

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Atlantic bluefin tuna in open blue water, a heavy steel-blue torpedo with silvery flanks, short yellow finlets and a stiff crescent-shaped tail. Atlantic Bluefin Tuna Atlantic goliath grouper resting beside a reef ledge, a broad mottled brown fish with a very large mouth, small high-set eyes and rounded fins. Atlantic Goliath Grouper Great barracuda hovering in clear blue water, a long silver fish with a pointed head, jutting lower jaw, dark flank blotches and a deeply forked tail. Great Barracuda
3 profiles

Other Ocean Hunters

Bears, birds and reptiles that earn their living hunting in the sea.

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An emperor penguin standing upright on sea ice, showing its black head and back, white belly, and the yellow-orange patches on its neck and lower bill. Emperor Penguin A leatherback sea turtle swimming in open blue water, its dark blue-black skin flecked with pale spots and its ridged, teardrop-shaped carapace tapering to a point. Leatherback Sea Turtle A polar bear with thick cream-white fur, a long neck and small rounded ears standing on pack ice, its black nose and dark eyes clearly visible. Polar Bear

Worth comparing

Pairings that explain something

Each of these has a written comparison behind it, because the two animals illuminate each other: same niche in different oceans, same prey by different methods, or the same body plan at wildly different scale.

All comparisons
Orca
Sperm Whale

Two toothed whales, two strategies

Orca vs Sperm Whale: Two Toothed Whales Compared

The largest dolphin and the largest toothed predator share every ocean but divide it by depth, diet and the way their families are organized.
Great White Shark
Saltwater Crocodile

A warm-bodied fish and a patient reptile

Great White Shark vs Saltwater Crocodile: Fish, Reptile

The largest predatory fish and the largest living reptile reach nearly the same length by opposite routes, one on warm muscle and one on patience.
Sperm Whale
Giant Squid

A predator and its prey, known almost entirely at second hand

Sperm Whale vs Giant Squid: Predator and Prey

One of the ocean's best-known feeding relationships rests on beaks, scars and stomach contents. No encounter between the two has ever been filmed.
Giant Squid
Colossal Squid

A measurement problem more than a size difference

Giant Squid vs Colossal Squid: Longer or Heavier?

Two of the largest invertebrates known, separated by a measurement problem: one is much longer, the other far heavier, and both samples are tiny.

Background reading

Why the ocean produces these animals

A predator only makes sense in context. These guides cover the structure of the ocean, the flow of energy through it, and the pressures that decide which hunters survive the century.

Cross-section of the ocean showing a sunlit coral reef and kelp forest in the shallows, dim blue midwater below, and the dark deep sea floor beneath.

Ocean habitats

Marine Ecosystems: Ocean Zones and Habitats

How the ocean's vertical zones and coastal habitats shape which predators live where, from sunlit reefs to the cold, dark abyss.

12 minute read
Layered ocean scene showing sunlit plankton near the surface, a swarm of krill and schooling fish below, and larger predators cruising in the deeper blue.

Ocean energy flow

Ocean Food Webs: Plankton to Apex Predators

How sunlight becomes plankton and plankton becomes sharks and whales, why energy is lost at every step, and why top predators are rare.

12 minute read
A length of discarded fishing net drifting in open blue water, with a healthy coral reef and distant circling sharks visible beyond it in clearer water.

Threats and recovery

Ocean Predator Conservation: Threats and Recovery

The pressures that actually drive ocean predator declines, from fishing and bycatch to warming seas, and the measures with real evidence behind them.

14 minute read

How the numbers are chosen

Ranges, not record claims

Animal measurements vary by sex, region and how the animal was measured, and the most dramatic figures are often the least documented. Every profile reports the range that published sources actually support, notes where researchers disagree, and links to the assessments and agencies the figures came from.

Sources and methodology Editorial policy