A true symbol of the sea, the starfish is one of the most remarkable creatures you will find in the depths of the underwater world. This curious little echinoderm has many special features and qualities, one of the most impressive of them being its ability to regenerate its own missing limbs over time. Even though this unique ability differs from one species of starfish to another, it is actually a common trait among many species. Also, its development, lifespan and intriguing anatomic constitution have been studied by scientists very closely throughout the years, leading to some startling results.
The starfish – lately renamed sea star – is a star-shaped echinoderm that can be found basically in every ocean of the world. It can thrive anywhere from ocean beds with depths of up to 6,000 feet and places like the Arctic, featuring the least favorable conditions that most sea creatures would be able to endure, to the tropics and right below the surface, close to the most colorful coral reefs you can visit. Well-versed predators, starfish have an uncommon vascular system, tube feet that are operated by a hydraulic system and a complex life cycle that allows them to reproduce both sexually and asexually.
Starfish feature a center disc and limbs located around it at equidistant intervals, forming the shape of a star. They are opportunistic predators, and their mouths can usually be found at the center of the disc or lower surface. One of the most curious qualities of starfish is their unique circulatory system. Starfish don’t actually have blood. Instead, their water-based vascular system uses an intricate network of canals and hydraulic systems designed to elegantly accommodate locomotion and fast movements. Also, even though their nervous system is quite basic, starfish are highly sensitive to touch and can sense changes such as those in the pressure and temperature of the water around them, as well as the effects of light, heat and orientation changes.
So here’s the big one: regeneration. Many species of starfish are actually able to regenerate their limbs after amputation. Whether they were cut off by a predator or due to other unfortunate events, the limbs of a starfish can actually grow back, given enough time. It takes anything from a few months to a year for a starfish to grow back a limb completely, and in the case of some species, the disc has to be undamaged and the starfish has to retain at least 2-3 of its limbs in order for regeneration to be possible. Another interesting fact about the starfish’s remarkable abilities is that the cut off limb can even grow a new disc in some cases and continue to thrive on its own.
So does the fact that starfish are able to grow back limbs mean that they’re indestructible or capable to practically live forever? Although that might be a viable assumption, starfish are actually quite fragile, and their lifespan is only about 30-34 years at most. Starfish reach sexual maturity in about 2 years and are commonly known to live only about 10 years on average. Nevertheless, this remarkable little creature that weighs only 80 grams is an actual evolutionary marvel, its regenerative capabilities having baffled scientists who have spent many years studying its unique traits and qualities.