Starfish, also known as sea stars, are fascinating marine creatures with some unique biological traits. One of the most intriguing facts about starfish is that they have neither a brain nor blood. Instead of a brain, starfish have a decentralized nervous system that operates through a complex network of nerve cells spread throughout their body. This system allows them to respond to their environment, move, and coordinate their actions.

Starfish also lack blood. Instead, they use a hydraulic system to circulate a fluid called seawater, which serves a similar function to blood. This water vascular system helps them move and capture prey. It operates through tube feet located on the underside of their arms. These tube feet can extend and retract, allowing the starfish to grip surfaces and objects, facilitating movement and feeding.

Historically, starfish have been known to scientists for centuries. The earliest records of starfish date back to ancient Greece, where they were described by Aristotle. Throughout history, their unique anatomy has intrigued marine biologists and naturalists, leading to numerous studies and observations.

Starfish come in various colors and sizes, and they can regenerate lost arms, which is a remarkable feature. This ability to regenerate has contributed to their survival in diverse and often harsh marine environments. Despite their lack of a brain and blood, starfish are highly adapted to their ecological niches, demonstrating the incredible diversity of life in the ocean.