Happy Wednesday!
Catch the solar eclipse last week? Here’s some video highlights if you missed it!
Here’s what we’ve got this week:
TRIVIA
Ocean’s fastest 🌊
What is the fastest sea creature?
Explanation at the end!
ANIMAL FOCUS
Tuna 🐟
Bluefin tuna are (partially) warm-blooded! Most fish are the same temperature as the water around them. Bluefin have special blood vessels that trap heat from their muscles. This can make them 18°F warmer than the water, helping them stay fast, hunt, and even see better in cold water! 🌡️
Tuna can’t stop swimming! Most fish can pump water over their gills while staying still. Tuna have to keep swimming so water flows over their gills to give them oxygen. Even when they “rest,” they’re still gliding forward. 🐟
A school of tuna can be bigger than some towns! Some schools with thousands of tuna can stretch up to 19 miles across! 🚌
Tuna can swim faster than some speedboats! Their bodies are shaped like torpedoes, which helps albacore swim over 50 mph! They have one of the most efficient bodies in nature. 💨
A single tuna can cost as much as a luxury home! Bluefin are among the most expensive seafoods, and some have sold for over $3 million at Japanese auctions. 💰
EVER WONDER?
How do fish know which way is “up”? 🧭
Ever wonder how fish know which way is up? They use several clues:
Tiny balance crystals 💎
Inside a fish’s head are tiny balance organs. They contain small crystals called otoliths, which sit on hair cells. When a fish tilts or turns, gravity moves the crystals, which bends the hairs under them. The fish’s brain uses this information to tell which way is up.
Trusting their eyes 👀
Fish can look for:
Light coming from above
Darker water below
Which direction plants are growing
Feeling the pressure 🎈
Fish have a gas-filled sac called a swim bladder.
Near the surface, it gets bigger
In deeper water, it gets smaller
The fish’s brain uses these changes to help control depth.
Their lateral line senses movement 🐟
Fish have a special sensing system called the lateral line that runs along both sides of their body. It can detect:
Movements in the water
Vibrations
Changes in water pressure
It’s like a built-in motion detector that helps fish know where they are, even in the dark!
BRAIN TRIVIA
Logic & Math Puzzle: A coin is flipped 1,000 times. It lands on heads 560 times. Does that sound like a fair coin?
Pelayo Salinas de Leon | Mangrove Photography Awards 2026
Thanks for reading! Stay curious!
- Steve
P.S. The Black Marlin (82 mph) is faster than the Sailfish (68 mph), Swordfish (62 mph), Yellowfin Tuna (50 mph), and Shortfin Mako Shark (46 mph).
P.P.S. Have an animal or science question you’d like us to feature? Just hit ‘Reply’ and tell us!