The National Aquarium and its Animal Care and Rescue Center are temporarily closed in response to COVID-19 (Coronavirus). CLICK HERE for more information.

Seaside Wonders: Sea Stars and Urchins

5 Keys to Survival, According to Echinoderms

Echinoderms—a phylum of marine animals that includes starfish, sea urchins, sand dollars and sea cucumbers—have a few tricks up their sleeve when it comes to surviving dangerous waters. To avoid becoming the next meal for crabs, sharks, sea birds, otters and other predators, these naturally armored animals employ the following tactics:

1. Be tough.

An echinoderm’s skeleton is its shield—the effort involved in consuming these creatures can be a deal-breaker for predators.

2. Grow a spine.

Or many of them. Sea urchins depend on their long, pointy spines to deter hungry predators. Unfortunately, this defense isn’t enough to keep away adorable sea otters, who crack open their fresh, spiky snacks on rocks.

3. Be resourceful.

In the case of sea cucumbers, the best available defense could be toxic to enemies. These echinoderms can release a poisonous chemical known as holothurin.

4. Be open to new opportunities for growth.

Echinoderms are armed with the power of regeneration—a useful tool if you’re a sea star. These sea creatures can simply disconnect their arm, flee to safety and re-grow the lost appendage later.

5. Stay cool as a cucumber in the face of adversity.

A sea cucumber, that is. These odd animals sometimes respond to potential predators by discharging sticky threads to ensnare their enemies, or by expelling their internal organs, which they can later regenerate. See this crazy defense mechanism in action in the video below:


Back to the Top