Sea turtles are some of the oldest creatures on Earth, having been around for over 100 million years.

Pufferfish inflate their bodies with water or air when threatened.

Squids have a unique mode of locomotion called jet propulsion. By expelling water from their mantle cavity through a siphon, they can rapidly propel themselves through the water with great speed and agility.

Unlike most other fish species, it is the male seahorse that becomes pregnant and carries the developing embryos. The female transfers her eggs to a specialized pouch on the male's abdomen, where they are fertilized and remain until they hatch.

The stinger at the base of the tail is equipped with venom glands and can be used in self-defense if the stingray feels threatened.

Dolphins use echolocation, a biological sonar system, to navigate their underwater environment, locate prey, and communicate with each other.

Despite their lack of a centralized brain, jellyfish are still highly efficient predators and can exhibit complex behaviors such as hunting and reproduction.