Mail Buoy: May 11

Question:

Does the twilight zone have any dolphins?

Brody P., Tremont Middle School

Answer:

That's a trick question, Brody!

While most common dolphins tend to keep to shallow depths, some dolphin species do spend time in the twilight zone! Specifically offshore ecotype bottlenose dolphins. Spinner dolphins in Hawaii also dive into the mesopelagic (middle ocean) to feed at night when their prey is closer to the surface.

In fact, many large pelagic animals rely on the twilight zone for food. Beaked whales, whale sharks, basking sharks, and blue sharks (among others) have all been shown to spend time in the twilight zone, even some penguins and seals! Every time we study how much time these animals spend in the twilight zone, it’s always more than we thought. We are just now beginning to understand how important the twilight zone is to these larger predators at the top of the food chain.

-Simon Thorrold, WHOI biologist