The mantis shrimp can punch at 50 mph

A single teaspoon of soil contains more microorganisms than people on Earth

A teaspoon of soil harbors more microorganisms than Earth's human population

Skeletal muscle

Masseter muscle: Strongest muscle relative to size

Concrete

Human bones are stronger than concrete — ounce for ounce, bone is stronger than steel

Vehicle registration plates of California

Blue whale's heart is the size of a small car

Octopuses have three hearts, blue blood, and nine brains

Octopuses have three hearts, blue blood, and nine brains — one central, eight in their arms

Stellar black hole

Schwarzschild radius ≈ 3 km for solar-mass black holes