fbpx

KidsKonnect

Marine Animals Facts & Worksheets

There have been records of more than 200,000 marine species, and it's possible that two million more are yet to be recorded.

Search for Worksheets

Worksheets /Science /Marine Animals Facts & Worksheets

Premium
Not ready to purchase a subscription? Click to download the free sample version   Download sample

All the plants, animals, and other organisms that live in the saltwater of seas, oceans, or the brackish water of coastal estuaries, are referred to as marine life, sea life, or ocean life.

See the fact file below for more information on Marine Animals, or you can download our 34-page Marine Animals worksheet pack to utilize within the classroom or home environment.

Key Facts & Information

MARINE LIFE

  • All animals, plants, and organisms that inhabit Earth’s saltwater seas and oceans are referred to as marine life. Every organism, from the smallest plankton to the largest whale, contributes to the healthy operation of these amazing, intricate ecosystems.
  • The majority of living things originated in marine environments. Oceans account for roughly 90% of the world’s living space by volume. Fishes, which only existed in water, were the first vertebrates to appear. Amphibians, which spend some of their lives on land and some in water, are the result of the evolution of some of these.
  • There have been records of more than 200,000 marine species, and it’s possible that two million more are yet to be recorded. The smallest marine species are phytoplankton (0.02 micrometers), while the largest known animal, the blue whale (33 meters (108 feet)), resides in the vast expanse of waters.

MARINE ANIMALS & THEIR HABITATS

  • Intertidal – The intertidal zone, where land and sea meet, is the shore between high tide and low tide. During high tide, the intertidal zone is submerged, while at low tide, it is exposed. 
  • Being submerged in water and exposed to the air at various times of the day is a challenge for the plants and animals that inhabit this area.
  • Sea stars, snails, seaweed, algae, and crabs can be found in the rocky shoreline of intertidal zones. By securing themselves to the rocks, barnacles, mussels, and kelps can survive in this environment.
  • Mudflats – Mudflats consist of the mud and silt brought in by seas, oceans, and tributaries. When the tide comes in, mud and silt are deposited in bays and lagoons. Muddy quicksand is the result of the water’s interaction with the mud and silt in mudflats.
  • Marine mollusks, crustaceans, and worms like lugworms, oysters, cockles, and snails call mudflats home. Additionally, this habitat serves as a crucial breeding ground for numerous fish species.
  • Mangroves – Trees and shrubs that have prop roots that look like stilts and perch on the water. Where land meets water, mangroves develop along the coast. They are unique in their ability to survive in low-oxygen soils and brackish waters that are flooded with salt water at high tide.
  • Mangrove root systems are home to a variety of organisms, including snails, barnacles, bryozoans, tunicates, mollusks, sponges, polychaete worms, isopods, amphipods, shrimp, crabs, and jellyfish. Crabs are the most common invertebrate that thrives in the mangrove canopy.
  • Coral Reefs – An underwater ecosystem that is characterized by reef-building corals. Colonies of coral polyps are held together by calcium carbonate and form reefs.
  • Many different kinds of marine life, including various sponges, oysters, clams, crabs, sea stars, sea urchins, and fish, thrive in coral reefs. Ecologically, coral reefs are also connected to nearby communities of seagrass, mangrove, and mudflat.
  • Estuaries – Where rivers meet the sea, estuaries are protected bodies of water where salty and nutrient-rich freshwater mix with salty water and sunlight reaches shallow depths.
  • Animals that frequent estuaries include a wide variety of reptiles, including raccoons, opossums, skunks, fish, crabs, lobsters, and other shellfish, marine worms, and shore and seabirds.
  • Open Ocean – The part of the ocean that isn’t near the coast is called the pelagic zone or the open ocean. Here you will probably discover the most marine life species.
  • Wave and wind activity, pressure, water temperature, and prey have an impact on species here. Because this region extends far, animals must travel far to eat. Sea turtles travel thousands of miles between their feeding grounds and where they mate.
  • Other marine habitats include kelp forests, seagrass meadows, oyster reefs, tidewater glaciers, and salt marshes.

PREHISTORIC ORIGINS

  • Marine invertebrates were the earliest animals; vertebrates followed later. Eukaryotic animals with multiple cells stand out from plants, algae, and fungi due to the absence of cell walls. 
  • Apart from vertebrates in the chordate phylum, marine invertebrates are animals that live in the ocean. There is no vertebral column in invertebrates. Some have developed a hard shell or exoskeleton.
  • Apart from Dickinsonia, the most well-known early animal fossils are the rather modern-looking cnidarians, which include coral, jellyfish, sea anemones, and Hydra. 
  • These fossils could have been found around 580 million years ago. The first animal larger than a few centimeters in length was the Ediacara biota, which thrived for 40 million years before the Cambrian. 
  • Many, like Dickinsonia, were flat and had a quilted appearance. They were so strange that it was suggested that they be classified as their own kingdom, Vendozoa.

EARLIEST MARINE ANIMALS

  • Sponges can live for hundreds or even thousands of years. They are multicellular organisms with pores and channels in their bodies that allow water to flow through them.
  • Anomalocaris was the largest and scariest predator in the seas during the Cambrian Period. The longest found intact specimens are up to three feet long.
  • Giant marine reptiles, known as Ichthyosaurs, ruled the sea when dinosaurs ruled the land. They were the planet’s first giants and could reach 50 feet in length, about the same size as modern sperm whales.
  • Marine scientists agree that the bowhead whale (Balaena mysticetus), a species of baleen, has the longest lifespan of all marine mammals. This Arctic dweller may live 200-plus years.
  • In contrast to all the species above, the Sign Eviota (Eviota sigillata), a tiny coral reef fish, completes its entire life cycle within an eight-week period. 

MARINE ANIMALS – VERTEBRATES

  • Marine Fish – Fish that live in seawater is known as saltwater fish or sea fish. Saltwater fish can swim by themselves or live in a large group known as a school.
    • Jawless fish – They are the earliest known species. They: (a) have long, cylindrical bodies, (b) lack paired fins and scales, (c) and suction feed from a muscular mouth with rows of teeth. There are two types: lampreys and hagfish.
    • Cartilaginous fish – The following are characteristics of cartilaginous fish: scales, paired fins, and paired nostrils. Instead of bone, its skeletons are made of cartilage. Cartilage is supportive tissue that lacks the calcium that makes bones rigid. Compared to the bone, cartilage is softer and more flexible.
    • Bony fish – All bony fish belong in the class Osteichthyes. They are cold-blooded vertebrates that swim with fins and breathe through their gills. Bony fish are distinguished by several characteristics: a bone structure with scales, jaws, paired nostrils, paired fins, and one pair of gill openings.
    • Teleosts – They dominate both marine and freshwater habitats and are the most advanced of all fishes. Due to a few key adaptations, teleost fish species can be found all over the world and have developed remarkable diversity for a group of vertebrate animals.
    • Marine Tetrapods – They are vertebrates that are only marginally adapted for marine environments and get most or all of their food from the sea. Cetaceans, pinnipeds, sirenians, sea otters, sea bats, and polar bears are all examples of marine mammals in this category, as are seabirds.
  • Marine reptiles – Reptiles that have developed secondary adaptations for aquatic or semi-aquatic life in a marine environment. Extant creatures include sea turtles, sea snakes, and marine iguanas. Saltwater crocodiles can also be identified with this group but are not truly marine.
  • Marine birds – Also called seabirds or pelagic birds. Most of them eat fish, crustaceans, mollusks, or aquatic vegetation because they live in the ocean. They typically have layers of fat to keep them warm and dense, waterproof feathers.
  • Some have feet that are completely or partially webbed, making them ideal for swimming, catching fish in shallow water, and performing precise dives. Seabirds generally live longer than other wild birds; the majority live for 50 years on average.
  • Marine mammals – Aquatic mammals whose survival depends on the ocean and other marine ecosystems. Manatees, sea otters, seals, whales, and polar bears are among them. They are a loose group that only share one thing in common: their reliance on marine environments for food and survival.

MARINE ANIMALS – INVERTEBRATES

  • The ocean’s most diverse group of animals is invertebrates. Mollusks, crustaceans, and corals are examples of common marine invertebrates.
  • There are more than 50,000 species of mollusks, an invertebrate group. They are animals with soft bodies that can either have a hard shell on the outside or no shell at all. Octopus and squid are examples of mollusks, as are abalone, conch, oysters, and clams.
  • Subcategories of invertebrates include crustaceans, which are closely related to spiders and insects. They typically have a hard crust or shell covering their body. Shrimp, krill, lobsters, and crabs are all crustaceans.
  • Corals are referred to as “colonial organisms” because many distinct creatures live and develop close to one another. Coral polyps are individual, minute organisms that make up large coral colonies. 
  • One type of coral is the stony, shallow-water coral, which builds reef habitats. Additionally, there are soft corals and deep-sea corals that inhabit cold, dark waters.

Marine Animals Worksheets

This fantastic bundle includes everything you need to know about Marine Animals across 34 in-depth pages. These ready-to-use worksheets are perfect for teaching kids about Marine Animals. All the plants, animals, and other organisms that live in the saltwater of seas, oceans, or the brackish water of coastal estuaries, are referred to as marine life, sea life, or ocean life.

Complete List of Included Worksheets

Below is a list of all the worksheets included in this document.

  1. Marine Animals Facts
  2. Water is Life
  3. The Fishes
  4. The Most Beautiful Fishes
  5. Marine Birds
  6. Marine Reptiles
  7. Mammals – The Cetaceans
  8. Mammals – The Pinnipeds
  9. Mammals – The Sirenia
  10. Mammals – The Fissipeds
  11. Marine Oddities
  12. Risks and Benefits

Frequently Asked Questions

What is the largest marine animal?

The largest marine animal is the blue whale, which can grow up to 100 feet long and weigh up to 200 tons.

How do marine animals breathe underwater?

Marine animals have adapted to extract oxygen from the water through gills, which extract dissolved oxygen from water as it flows over them.

How do sea turtles navigate the ocean?

Sea turtles use a combination of magnetic fields, ocean currents, and visual cues to navigate the ocean during their migrations.

What is the difference between a dolphin and a porpoise?

Dolphins have longer snouts, curved dorsal fins, and more conical teeth, while porpoises have shorter snouts, triangular dorsal fins, and spade-shaped teeth.

Do all marine animals live in the ocean?

No, not all marine animals live in the ocean. Some marine animals, such as manatees and river dolphins, live in freshwater environments.

Link/cite this page

If you reference any of the content on this page on your own website, please use the code below to cite this page as the original source.

Link will appear as Marine Animals Facts & Worksheets: https://kidskonnect.com - KidsKonnect, March 5, 2023

Use With Any Curriculum

These worksheets have been specifically designed for use with any international curriculum. You can use these worksheets as-is, or edit them using Google Slides to make them more specific to your own student ability levels and curriculum standards.

Related Resources