It’s a bird! It’s a plane! It’s … special adaptations to help animals thrive in the ocean!
Marine critters have evolved some pretty unique techniques to survive and thrive in our oceans. Read on to learn about some special ocean superpowers.
Camouflage with chromatophores
Ever wonder how octopuses can change color? Cephalopods have specialized cells in their skin called chromatophores. Each chromatophore cell has a stretchy sac called the cytoelastic sacculus that is filled with pigment, which can be red, yellow, brown or black in color. When the muscles around the cell tighten, they pull the pigment sac wider, meaning more pigment is visible on the octopus’ skin.
Unlike other species, octopuses don’t have a hard shell or sharp spines to protect themselves. Camouflage is their best bet for avoiding hungry predators. By using their chromatophores and changing the texture of their skin (yes, they can do that too!) octopuses can seamlessly blend into rocks, corals and sponges. They can also use color to warn predators, like the highly-venomous blue-ringed octopus who flashes its blue rings to tell other animals to stay away.
Detect electric fields with ampullae of Lorenzini
Ampullae of Lorenzini are sensory organs that allow animals to detect electric stimuli in the water. They’re found in cartilaginous fishes, which includes sharks, rays and chimaeras, and in some other finned fishes like sturgeon. When they were originally described by scientist Stefano Lorenzini in 1678, scientists weren’t sure what they were used for. It wasn’t until the 1900s, and the availability of more precise equipment, that scientists discovered their true purpose. Each individual ampulla has a small cavity that contains pouches called alveoli, which are lined with many sensory receptors. When the organ detects a change in electric fields, it sends a message through a nerve connected to the animal’s brain. This helps the animal better detect prey, even when visibility is poor or the prey is buried in the sand, for example.
Glow with bioluminescence
Some ocean animals, including the American pocket shark, deep-sea anglerfish and Hawaiian bobtail squid, can glow thanks to something called bioluminescence. Bioluminescence is a chemical process in which an organism emits light. It’s considered a “cold light”, which means only a small percentage of the light contains heat, unlike the light produced by fire or the sun’s rays. The light is produced by a compound called luciferin, which releases light when it reacts with oxygen.
A sudden bioluminescent light can surprise and stun potential prey, or illuminate them to make it easier for the predator to see. Some animals, like the anglerfish, use their light as a lure in the deep sea to draw prey to them. As prey, it can distract or misdirect a predator for a time, allowing the prey to quickly escape. A glowing light can also signal to predators that the potential prey is toxic, or even warn others that a predator is near.
Knock out your foes with nematocysts
If you’ve ever been stung by a jelly at the beach, you have personal experience with nematocysts. Cnidarians (the phylum that includes corals, jellyfish, anemones and more) make small stinging cells called nematocysts that resemble tiny harpoons and are used to ward off predators or capture prey. Because nematocysts are activated by physical or chemical triggers, some cnidarians can sting humans even after they die, or if a tentacle becomes detached. Although most stings are mild, some (like from a Portuguese man-of-war and some species of jellies) can cause serious health problems, including death. A good rule of thumb? Keep a healthy distance from ocean animals, and everyone is happy.