The stoplight loosejaw, the marlin, & Extreme Life of the Sea
Mia Cox
Updated on March 22, 2026
Challenging environments can help create some of the most marvelous evolutionary solutions. Two examples: The stoplight loosejaw and the marlin.
The Stoplight Loosejaw is a small, deep sea dragonfish that has an “invisible” red headlight that hides his presence from possible predators. The marlin, a huge fish that can clock up to 80 km/h (50 mph), has “heat-producing tissue beneath the brain and adjacent to the eyes” that helps their brains and eyes work faster. Steve Palumbi, co-author of Extreme Life of the Sea, explains these two wonders in this Cal Academy video.
Watch more incredible marine life videos, and more from Cal Academy.