Imagine a world where the only food is dust particles shimmering in the morning sunbeams. This dust, while nutritious, is a challenge to catch. That’s the reality for many creatures living in the vast, open ocean. Food is scarce, and the environment is unforgiving. This has led to the evolution of bizarre and ingenious feeding strategies.
As marine biologist Peter Herring famously said, we catch “only the slow, the stupid, the greedy, and the indestructible.” But beneath the surface, a complex and fascinating game of survival is played out.
Many deep-sea animals hunt and eat their prey in a way we might imagine a lion hunting its prey, chasing it down and attacking. However, many others have developed unique methods to survive in this challenging environment.
Take, for example, the creatures that essentially create a screen to trap tiny particles from the water. Imagine yourself trying to collect dust with your hands or mouth. It would be a frustrating task. But if you had a fine window screen, you could walk through your house and trap the dust particles on the mesh. That’s what many pelagic animals do, creating a screen to catch the microscopic food particles floating in the water.
This strategy is also employed by creatures living on the seafloor, such as feather stars and feather duster worms, who have the advantage of being stationary in a current.
Given the vastness of the ocean and the scarcity of food, it makes sense that some animals have evolved to eat ever-smaller things. This is where the larvae of eels come in. Contrary to popular belief, eel larvae don’t resemble their adult forms. Instead, they are long, transparent leaves with tiny heads. Researchers believe these larvae absorb nutrients directly through their skin, storing energy that will later fuel their transformation into glass eels.
Another fascinating example is the gymosomes, often called ‘sea angels.’ These creatures are cute little slugs with wings, but they possess a remarkable array of tools inside their head for catching their favorite prey: Limacina snails.
When a gymosome spots a Limacina, it uses its soft tentacles to grab the snail and maneuver it into the perfect position. Then, long, sharp hooks, known as ‘eversion,’ are squeezed out of sacs on its head. These hooks, like cocktail forks, can reach deep inside the Limacina’s shell, pulling the soft body out.
But finding food in the open ocean is only half the battle. Avoiding becoming food is just as important. With limited hiding places and predators often faster than their prey, deep sea creatures need innovative ways to protect themselves.
Some evolve to become larger, but this is not always the case. While there are whales, sharks, and large fish and squid, the majority of species in the open ocean haven’t evolved to increase in size.
Others have developed toxicity, venom, or a bad taste to deter predators. But for those who can’t run, fight, or taste bad, the only option is to hide. This often involves blending in with the environment, such as hiding in the darkness or becoming transparent, allowing the background light to pass through them as if they weren’t there.
The life of a deep sea creature is a constant struggle for survival. They are constantly adapting, evolving, and playing a fascinating game of hide-and-seek in a world where food is scarce and danger lurks around every corner. Their unique strategies for finding food and avoiding becoming food are a testament to the power of adaptation and the beauty of the natural world.