Larval Blenny Fish
Photograph by David Liittschwager, National Geographic
It’s a fish-eat-fish world in the waters of the world’s oceans, and larvae may be the most vulnerable creatures of all. Larvae—the early form of some animals—are small, slow, and largely defenseless compared with their adult relatives. For many species, including this blenny, invisibility is the best bet for survival.
Hyrdomedusa
Photograph by David Wrobel, Seapics
In the dark waters near the Pacific Ocean seafloor a hydromedusa waves enough tentacles to appear rather like its ancient Greek namesake, Medusa. Medusae, which bud asexually from bottom-dwelling polyps, are just one stage of this jellyfish’s life cycle. Males and females release sperm and eggs, which spawn freely in seawater and form new polyps to begin the cycle again.
Pram Bug
Photograph by Solvin Zankl, Seapics
Though it’s only an inch (2.5 centimeters) long, the tiny Phronima crustacean is still a pretty vicious customer. Females prey on small marine animals called salps by using their mouths and claws to devour the salp’s insides and then hollowing out the corpse. The “pram bug” then lays her eggs inside the victim’s body cavity to create a mobile, gelatinous nest for her young.
Larval Flounder
Photograph by David Liittschwager, National Geographic
A translucent body disguises a larval flounder to keep it safe from predators. It will lose this defense mechanism later in life. Flounder undergo several striking physical transformations during their lifetimes. Very young flounder swim upright and have an eye on each side of their face. As they age the fish begin to swim on their sides and one eye slowly migrates until both are on the body’s “top side.”
Larval Squid
Photograph by David Liittschwager, National Geographic
This larval squid, seen in a Hawaiian laboratory, is largely transparent but boasts patches of bright color. Squid skin is full of pigment cells, which the animals can control by flexing and relaxing the muscles around them. Some squid use this ability to change colors quickly when threatened, feeding, or mating and can even adopt striped or rippled hues.
Glass Squid
Photograph by David Wrobel, Seapics
A glass squid, named for its nearly transparent body, cruises the deep, dark waters of the eastern Pacific Ocean. The light organs in the squid’s eyes and arms are called photophores—and they may serve as lures to help it to locate mates in the inky depths.
Jellyfish
Photograph by Bill Curtsinger, National Geographic
About half of all jellyfish species are bioluminescent—and nearly all deep-sea jellies have this ability. A jelly’s light comes from a natural chemical reaction and is often employed to keep predators away by startling or distracting them.
Antarctic Ice Fish
Photograph by Russ Hopcroft, UAL/Census of Marine Life
This Antarctic ice fish is one seriously cool customer. Natural antifreeze allows it to survive and even thrive in water temperatures that would freeze the blood of any other known fish. Scientists are learning that the frigid waters around both Poles teem with more types of life than they previously imagined.
Mantis Shrimp Larva
Photograph by David Liittschwager, National Geographic
This mantis shrimp larva appears a bit insubstantial. But when grown the crustacean can deliver what might be, pound for pound, the animal kingdom’s most powerful smackdown. The shrimp can unleash its hammer-shaped front leg at an incredible speed of 75 feet (23 meters) a second to generate forces more than a hundred times its own body weight and splinter the shells of snails and other prey.
Sunflower Sea Star
Photograph by Emory Kristof, National Geographic
A sunflower sea star sits nearly unseen on Bowie Seamount, a submerged volcano off the British Columbia coast. These predators can boast three-foot (one-meter) arm spans and use their sucker-laden appendages to snatch up everything from clams to snails and even other sea stars. Though they appear to be sedentary, these animals can use their thousands of tiny feet to move as fast as three feet (one meter) a minute.
