We explain what sea animals are, what types exist and their characteristics. Also, examples and which ones are the most dangerous.
What are marine animals?
Marine animals are those that are adapted to life within the sea, on its surface or on its shores. Given that our planet is two-thirds of its surface covered by water, marine life encompasses an enormous and diverse number of animals, spread across the five oceans and adapted to their specific habitats.
Among marine animals are the descendants of the oldest known organisms. In fact, as far as we know, life had its beginnings in the primitive oceans of the Precambrian geological era billions of years ago.
However, not all life forms have the same origin, since many species of reptiles and marine mammals come from land-based species, which adapted again to the ocean.
The sea is also home to millions of species of microorganisms and plant species which play a very important role in the oxygenation of the planet. In addition, they support the rest of the marine food chain.
In other words, the oceans are an important source of biodiversity in the world and constant food for various non-marine species, including humans themselves.
See also: Aquatic ecosystem
Types of sea animals
Very broadly, we can classify marine animals according to the different regions of the aquatic mass of the oceans in which they live. We have like this:
- Surface animals. The closest to the Sun and therefore accustomed to the warmest and brightest waters, where algae and plankton abound, but also predators.
- Reef animals. They form extensive communities around coral, stones and kelp forests of various types, in some of the most biodiverse places on the planet, equivalent to tropical jungles, but under the sea.
- Deep animals. They live in colder, darker waters, at greater depths, in a more exclusive and challenging habitat.
- Abyssal animals. Inhabitants of the deepest, darkest, icy and inhospitable regions of the sea, to which sunlight does not reach and which are under immense environmental pressures.
Characteristics of sea animals
sea animals are very diverse in nature since they are distributed throughout diverse underwater environments and integrated into highly specific food chains.
Thus, it is possible to find representatives of practically all types: microorganisms or microscopic animals; invertebrates such as sponges, worms, jellyfish and mollusks; arthropods; echinoderms; a wide variety of bony and cartilaginous fish; aquatic life mammals; reptiles and amphibians, and on the surface, traveling on land, air and water, different species of birds.
However, among such a diversity of life forms, we can distinguish large groups according to their respiration. Some breathe through underwater mechanisms like the gills. Instead, others still have lungs to breathe air being forced to rise to the surface from time to time to breathe.
Similarly, marine animals differ from terrestrial animals in that its extremities are adapted to movement within the aquatic fluid so the presence of legs is replaced by fins, even in those animals that evolutionarily come from a terrestrial habitat.
The most dangerous marine animals
In general terms, Marine life does not represent a threat to humans although unfortunate encounters do exist and occur from time to time. Human beings are not part of any food chain in the ocean, so no animal considers them as potential food, except by mistake.
That does not mean that there are no animals with the potential to harm us, such as:
- The shark Contrary to what movies make us believe, cases of shark attacks are extremely rare and accidental, although possible. Of the majority of shark species, only a few are capable of hurting a bather or a diver, and among them are the tiger shark or blue shark, the great white shark and eventually some blue sharks.
- Toadfish These species of reef fish have various names, such as scorpion fish, toad fish, salamander fish, but they have in common their camouflage that makes them look like a stone. Along with other species with bright and showy coloring, these animals have poison glands capable of inducing catastrophic failures in the body, whenever we step on them by mistake or eat them carelessly.
- The jellyfish. There is an enormous diversity of jellyfish of different sizes, from microscopic to several meters in length, such as the famous Portuguese War Ship (Physalia physalis). The latter is capable of killing a human being if it becomes entangled in its long, poisonous tentacles, which would lead to paralysis and death by drowning. He would do this, of course, without the jellyfish suggesting it at all.
List of sea animals
A necessarily partial list of marine animals would include the following:
- White shark (Carcharodon carcharias)
- Tiger shark (cuvier galeopig)
- hammerhead sharkSphyrna mokarran)
- Sardine (Sardine pichardus)
- Albacore tuna (Thunnus alalunga)
- Sea anemone (Actinaria sp.)
- Pillar coral (Dendrogyra cylindricus)
- Hermit crab (Birgus latro)
- Sea lobster (Palinurus elephas)
- stone fish (Synanceia horrida)
- Whale shark (Rhincodon typus)
- Blue whale (Balaenoptera musculus)
- Orca whale (Orcinus orca)
- Common seal (Phoca vitulina)
- Sea lion (Otaria flavescens)
- common octopus (Octopus vulgaris)
- Marine angelfish (Chaetodontoplus septentrionalis)
- Manta ray (Manta birostris)
- Brunette (Gymnothorax javanicus)
- Green mussel (Perna viridis)
- Portuguese warship (Physalia physalis)
- Barracuda (Sphyraena barracuda)
- Marine crocodile (Crocodylus porosus)
- common dolphin (Delphinus delphis)
- Spider crab (Macrocheira kaempferi)
- Marine iguana (Amblyrhynchus cristatus)
- imperial cormorant (Leucocarbo atriceps)
- common pelican (Pelecanus occidentalis)
- Seagull (Larus argentatus)
- Guasa grouper fish (Epinephelus itajara)
- Hawksbill turtle (Eretmochelys imbricata)
- Abyssal pelican fish (Eurypharynx pelecanoides)
References
- “Marine life” on Wikipedia (English).
- “Marine animals” in Animapedia.
- “The 6 most dangerous marine animals in the world” in Aquarium, coast of Almería.
- “Marine life” in National Oceanic and Atmospheric Administration (NOAA).
- “Ocean Animal Encyclopedia” in OCEANA.
