What Is A Phronima? The Sea Creature Inspiration Behind The Alien Movies

No matter what level of interest you have in movies, I’m sure you’ve heard about the Alien movie series, which began in 1979.

For those who are familiar with the franchise, you may already know about the origin of the idea for the scary alien creature from the movies.

If not, it’s time to introduce you.

This creature is called a Phronima, and its height is just one inch (2.5 cm). Thankfully, much smaller than the film alien creature.

Regardless, this fully transparent creature is deadly to creatures that are much larger than it is.

Why so?

Well, just like in the movie, the Phronima positions itself within the belly of a host fish or other sea animal where it then makes itself at home.

Phronima, inspiration for the alien movies.

What Is A Phronima?

Small, deep-sea amphipods, the genus Phronima belongs to the Phronimidae family. The organism is found across all oceans but those in the polar regions.

They are extremely small, measuring just 1 inch in length. The Phronima is a transparent organism with a small, dark patch on its head.

Phronima is a small, deep-sea amphipod.

Where Do Phronima Live?

The Phronima is a deep-sea creature that can be found in all oceans of the world.

Phronima are transparent, which allows them to live in deep waters where sunlight does not reach.

They are typically found 200-1100 meters deep in the water. Staying at the deeper levels during the day and coming up closer to surface at night.

Side picture of a Phronima

What Do Phronima Eat?

Phronima are a parasitic predator. By living inside the belly of another sea creature, they are able to feed off of the host’s nutrients.

Additionally, once attached to their host, they will begin excavating the inside of the host in order to make their host’s body the vehicle by which they’re able to travel through the ocean currents.

They are known to prey on fish, crustaceans, and plankton.

How Do Phronima Reproduce?

Females release pheromones that the males detect with their antenna and then ride or carry them until it is time for them to molt. Males push their sperm into the marsupium when the female is ready, and females are released afterwards. She releases the eggs into the marsupium a few hours later for fertilization.


Are Phronima Harmful To Humans?

There have been no reported cases of Phronima attacking humans, so the answer here is no.


I hope you have enjoyed learning a little bit about the Phronima.

While these creatures may not be as scary as the film alien, they are still a little creepy to say the least.