because they can not breath under water that long? because they can not breath under water that long?
"When kids say 'average' they are really getting themselves into trouble! Most sea urchins are mass spawners, producing several million eggs. If even a tiny percentage are fertilized, you will have thousands of live offspring. And only a small percentage of these survive in their planktonic form without starving or being eaten until they find a place to settle as tiny adult urchins. Of these, only a handful will survive to spawn (and perhaps none). If I were being mathematically and linguistically correct I would have to answer your question, "The *average* lifespan of an urchin is 10-12 days!"On the west coast the intertidal sea urchins that kids come in contact with, like purple sea urchins (Strongylocentrotus purpuratus), are thought to be able live as long as thirty years. " - (author:Henrik Kibak)shared by: Glen Corral
It depends on the type of urchin, anywhere from 4 to 150 years.
People live in the amazon.And under water but they can hold there breath long.
this this is a girls from il. who wants to know how long sea urchin's live yes, sea urchins live in hawia =)
some live under water for a year, others up to 2 or 3 years!
Not for long...they are amphibians and need to breath air.
If there are enough nutrients in the water, a plant can live on indefinately under artificial light. Just light and water alone would not be enough to support the plant for very long.
It is beacouse of their blowholes
Calms live about three feet deep in water, under the sand. They need water to live, and if something moves them they will still be in the water.
A man cannot live without water for a year, but can live without solid food for long periods, under extreme circumstances or medical control.
The Whirligig beetle breathes through gills under the water. They live in the water for long periods of time.