Top 15+ Marine Animals That Use Tools

Common Octopus The Ocean's Crafty Engineer

The common octopus (Octopus vulgaris) stands out as one of the most intelligent invertebrates on the planet, with remarkable tool-using abilities. These eight-armed wonders have been documented collecting coconut shells, jar lids, and discarded bottles to create protective shelters. In a behavior that requires foresight and planning, octopuses will gather suitable items, transport them sometimes over considerable distances, and then assemble them into defensive fortresses. Particularly impressive is their ability to carry these tools while moving in an awkward "stilt-walking" posture, demonstrating both dexterity and determination. This deliberate collection and transportation of objects for future use meets the stringent scientific criteria for tool use, placing octopuses among the most sophisticated marine tool users.

Bottlenose Dolphins Sponge-Wielding Hunters

Bottlenose dolphins (Tursiops truncatus) in Shark Bay, Australia have developed a remarkable cultural tradition of tool use that has been passed down through generations. These dolphins carefully select cone-shaped marine sponges and wear them over their rostrum (snout) as protective gear while foraging on the seafloor. This behavior, known as "sponging," allows them to probe the sandy bottom for prey while protecting their sensitive snouts from sharp rocks, stingray barbs, and other hazards. What makes this behavior particularly fascinating is that it appears to be culturally transmitted, primarily from mother to daughter, creating distinct "sponging lineages" within the population. Genetic studies indicate this behavior has persisted for over 180 years, representing one of the best-documented cases of material culture in marine mammals.

Sea Otters Rock-Wielding Shellfish Connoisseurs

Sea otters (Enhydra lutris) are perhaps the most well-known marine tool users. These charismatic mammals use rocks as anvils and hammers to crack open hard-shelled prey like clams, mussels, and sea urchins. What's particularly fascinating is their selective approach to tool choice—otters will carefully choose rocks of appropriate size and shape for specific prey items, demonstrating remarkable problem-solving abilities. Many sea otters even keep a favorite rock, storing it in a loose pouch of skin under their forearm for future use. Studies show that young otters learn this sophisticated feeding technique through observation of their mothers, with the skill developing gradually over their first year of life. This tool use is not just impressive but essential to their survival, allowing them to access the high-calorie foods necessary to maintain their elevated metabolic rates in cold ocean waters.

Veined Octopus Coconut Shell Architects

The veined octopus (Amphioctopus marginatus) demonstrates one of the most sophisticated examples of tool use among invertebrates. These remarkable cephalopods collect discarded coconut half-shells from the ocean floor and repurpose them as portable protective shelters. What makes this behavior particularly impressive is that the octopuses will stack two half-shells together, carry them beneath their bodies in an awkward "stilt-walking" motion across open seafloors, and then reassemble them into a spherical shelter when needed. This behavior, first documented in 2009 by researchers in Indonesia, represents a clear case of tool use as the octopuses transport the shells specifically for future use rather than immediate shelter. The premeditated nature of this behavior suggests advanced cognitive abilities that involve planning for future scenarios—a mental capacity previously thought to be limited to vertebrates.

Indo-Pacific Bottlenose Dolphins Shell Game Players

Indo-Pacific bottlenose dolphins (Tursiops aduncus) in Shark Bay, Australia have developed a sophisticated feeding strategy involving large empty shells. In a behavior scientists call "shelling," these dolphins will chase fish into large empty trumpet or helmet shells, then lift the shell to the surface, draining the water and forcing the trapped fish into their mouths. This impressive technique requires spatial awareness, planning, and dexterity. Researchers have observed dolphins intentionally positioning the shells for optimal fish capture, demonstrating their understanding of the tool's function. Like sponging, this behavior appears to be culturally transmitted within certain dolphin groups, with juveniles learning the technique through careful observation of experienced adults. The complexity of this feeding strategy highlights the dolphins' ability to manipulate objects in their environment to solve foraging challenges.

Decorator Crabs Living Camouflage Experts

Decorator crabs (family Majidae) employ a unique form of tool use by adorning their shells with living organisms and debris for camouflage. These ingenious crustaceans actively collect and attach items like sponges, algae, and anemones to specialized hooked setae (hair-like structures) on their exoskeletons. Far from random decoration, this behavior represents strategic tool use, as crabs select materials that provide chemical defenses or visual camouflage appropriate to their specific habitats. Research has shown that decorator crabs can distinguish between defensive and non-defensive organisms, preferentially selecting those that offer protection from predators. When transferred to new environments, many species will actively replace their decorations with locally appropriate materials, demonstrating remarkable environmental awareness. This sophisticated form of biological tool use helps these otherwise vulnerable crabs survive in predator-rich marine environments.

Blackspot Tuskfish Coral Anvil Users

The blackspot tuskfish (Choerodon schoenleinii) demonstrates remarkable tool use through its sophisticated feeding technique. These fish have been documented using coral outcroppings as anvils to crack open hard-shelled clams and shellfish. In a behavior caught on film by researchers on Australia's Great Barrier Reef, tuskfish were observed carrying clams in their mouths, then repeatedly throwing them against selected coral heads with precise, powerful movements until the shells cracked open. What makes this behavior particularly impressive is the fish's apparent ability to select appropriate anvil sites and to strike from the optimal angle for shell breakage. This discovery challenged previous assumptions about fish cognition, as it demonstrates complex problem-solving abilities and the capacity to use external objects as tools—cognitive skills once thought to be limited to mammals and birds. The behavior appears to be learned rather than instinctual, suggesting cultural transmission within tuskfish populations.

Hermit Crabs Shell Upgrading Specialists

Hermit crabs (family Paguroidea) exhibit tool use through their sophisticated manipulation of abandoned shells, which they adopt as portable homes. Unlike most tool users that employ objects temporarily, hermit crabs maintain a permanent relationship with their chosen tool, carefully selecting and modifying shells to suit their protection needs. When outgrowing their current home, hermit crabs will meticulously evaluate potential replacement shells for size, weight, and structural integrity before making the switch. In remarkable "vacancy chain" events, groups of hermit crabs will form queues arranged by size near a newly available larger shell, with each crab moving into the next size up once the sequence begins. Some species even modify their shells by adding anemones, which provide additional protection through their stinging tentacles—effectively using one living organism as a tool to enhance another. This sophisticated assessment and modification of external objects for personal use represents one of the clearest examples of tool use in crustaceans.

Archerfish Water Jet Marksmen

Archerfish (family Toxotidae) employ one of the most remarkable examples of tool use in the marine world by using water as a precision tool for hunting. These skilled predators shoot down insects and other small prey from overhanging vegetation by firing accurate jets of water from their specialized mouths. What makes this behavior truly impressive is the sophisticated physics involved—archerfish must compensate for light refraction at the water-air interface and adjust the force of their water jets based on the distance to their target. Research has revealed that archerfish can hit targets up to 3 meters away with impressive accuracy, and they can learn to improve their aim through practice and observation of successful shots by other fish. Young archerfish develop this skill gradually, with their accuracy improving significantly with experience. This sophisticated manipulation of water as a hunting tool demonstrates remarkable cognitive abilities, as the fish must perform complex calculations involving distance, force, and refraction to successfully capture prey.

Wrasses Anvil-Using Reef Dwellers

Various species of wrasses (family Labridae) have been observed using sophisticated tool-based feeding strategies similar to those employed by tuskfish. These colorful reef fish will carry hard-shelled prey items such as sea urchins, shellfish, and crustaceans to specific coral formations that serve as anvils. With remarkable precision, they then crack open the prey by forcefully throwing it against these natural tools. The orange-dotted tuskfish (Choerodon anchorago), a member of the wrasse family, has been particularly well-documented using this technique. These fish demonstrate impressive cognitive abilities by repeatedly using the same anvil sites, effectively establishing persistent "tool stations" within their territories. Research indicates these fish can adjust the force and angle of their strikes based on the size and hardness of the prey item, demonstrating an understanding of physics principles. This anvil-using behavior has now been documented across multiple wrasse species in different ocean regions, suggesting it may be a widespread cognitive adaptation within this diverse fish family.

Ants on Islands Sponge-Wielding Foragers

While not strictly marine animals themselves, certain ant species living on intertidal mangrove islands have developed a remarkable tool-using behavior involving marine materials. These ingenious insects, particularly from the genus Solenopsis, have been observed using sponge fragments, dried seaweed, and other absorbent materials as tools to transport liquid food sources back to their colonies. In a behavior scientists call "sponging," worker ants will drop these absorbent materials into sugary liquids, allow them to soak up the food, and then carry the saturated tools back to the nest where other workers can extract the nutrients. This sophisticated strategy allows the ants to efficiently harvest and transport liquid food sources that would otherwise be impossible to carry. What makes this behavior particularly impressive is its apparent absence in mainland populations of the same species, suggesting it's a specific adaptation to the unique challenges of island environments where liquid food sources might be especially valuable. This represents one of the few documented cases of tool use among insects and highlights the cognitive flexibility of these small but sophisticated invertebrates.

Cuttlefish Masters of Object Manipulation

Cuttlefish (order Sepiida), close relatives of squid and octopuses, demonstrate sophisticated object manipulation that borders on tool use. These intelligent cephalopods have been observed using shells, rocks, and other objects as shields or barricades for protection and ambush hunting. In laboratory settings, cuttlefish quickly learn to manipulate objects to solve problems, including using items to reach food or create shelters. Perhaps most impressively, they can coordinate their eight arms plus two specialized tentacles to manipulate objects with remarkable precision. While some scientists debate whether these behaviors fully qualify as tool use in the strictest sense, cuttlefish clearly show the cognitive foundation for tool utilization through their sophisticated environmental manipulation. Their large brains relative to body size (among the largest brain-to-body ratios of all invertebrates) provide the processing power for these complex behaviors. As research continues, cuttlefish may yet reveal more definitive examples of tool use that further challenge our understanding of invertebrate intelligence.

Polar Bears Ice-Wielding Hunters

While primarily known as terrestrial predators, polar bears (Ursus maritimus) spend much of their lives in marine environments and have been observed using tools while hunting in the water. In a behavior documented by researchers and indigenous hunters, polar bears will sometimes use blocks of ice as weapons when hunting beluga whales or walruses. The bears have been observed picking up large chunks of ice and hurling them at prey animals, either to stun them or to break through the ice where marine mammals are hiding. In some instances, polar bears position ice blocks and use them as platforms for hunting, effectively turning floating ice into tools that facilitate access to prey. While less extensively documented than tool use in some other marine species, these observations suggest cognitive flexibility and problem-solving abilities that help polar bears adapt to their challenging Arctic environment. As climate change reduces Arctic sea ice and forces polar bears to adapt their hunting strategies, researchers are watching closely to see if tool use might become more prevalent as these ingenious predators face new challenges.

Great Apes in Water Underwater Tool Users

While not exclusively marine animals, several great ape species have demonstrated fascinating tool use while in aquatic environments. Orangutans at rehabilitation centers have been observed using sticks as snorkels and as tools to fish for fruit floating in water. Even more remarkably, chimpanzees at a zoo in Belfast were documented using branches as poles to test water depth and to retrieve floating objects beyond their reach. These observations challenge our understanding of great ape cognition, suggesting that their tool-using capabilities extend into aquatic contexts despite their primarily terrestrial evolution. Some researchers propose that early human ancestors may have developed sophisticated tool use during a theoretical aquatic or semi-aquatic phase of evolution, making these observations particularly intriguing from an evolutionary perspective. While these examples involve captive great apes rather than wild marine species, they provide fascinating insights into the cognitive flexibility of our closest relatives and the potential adaptability of tool use across different environments.

Sharks Cooperative Hunters with Environmental Aids

Recent research has revealed that certain shark species may engage in behaviors that border on tool use. Thresher sharks (family Alopiidae) use their elongated upper tail lobes as tools to stun and kill prey fish. In a hunting technique documented by underwater photographers and marine biologists, these sharks accelerate toward schools of fish and then whip their tails overhead with incredible force, stunning or killing multiple fish with a single strike. This specialized use of a body part as an extension tool demonstrates remarkable hunting sophistication. Additionally, some bottom-dwelling shark species have been observed manipulating their environment in ways that approach tool use, such as Port Jackson sharks (Heterodontus portusjacksoni) which use their snouts to move objects and expose hidden prey. While these behaviors might not meet the strictest definitions of tool use, they demonstrate how sharks have evolved specialized techniques for environmental manipulation. As shark research continues with better underwater observation technologies, more examples of object manipulation and potential tool use may yet be discovered in these ancient and adaptable predators.

Conclusion: The Evolutionary Significance of Marine Tool Use

The discovery of tool use across such diverse marine species has profound implications for our understanding of animal cognition and evolution. These behaviors challenge the long-held assumption that tool use is primarily the domain of terrestrial mammals and birds with large brains. Instead, we now recognize that tool use has evolved independently across multiple lineages and environments, suggesting it represents a convergent solution to environmental challenges rather than a single evolutionary innovation. The presence of sophisticated tool use in octopuses—animals with nervous systems radically different from vertebrates—is particularly significant, as it demonstrates that complex cognitive abilities can evolve through entirely different neural pathways. Marine tool use also provides valuable insights into the environmental pressures that drive cognitive evolution, such as the challenges of accessing well-protected prey or navigating complex underwater terrain. As climate change transforms marine ecosystems, continued research on how these tool-using species adapt their behaviors will provide crucial windows into the cognitive flexibility that may determine which species thrive in our changing oceans. These discoveries ultimately remind us that intelligence takes many forms, and the capacity for innovation exists throughout the animal kingdom.