The octopus is one of the few animals on Earth with two hearts. In addition to its primary heart, it also has two smaller hearts that pump blood to the gills, allowing the octopus to better circulate oxygen-rich blood throughout its body.
Horseshoe crabs have blue blood due to the presence of copper-based hemocyanin, which helps transport oxygen. Their blue blood is also extremely valuable in the medical field, as it is used to test for bacterial contamination in intravenous drugs and medical devices.
Krill are tiny shrimp-like creatures that are among the smallest animals on Earth. Despite their small size, they are a crucial part of the ocean's food chain, serving as a primary food source for many larger marine animals like whales, seals, and penguins.
The blue whale is the largest animal on the planet, weighing up to 200 metric tons and measuring up to 30 meters (98 feet) in length. These gigantic creatures feed almost exclusively on tiny krill, consuming up to 40 million krill per day.
The common scallop has up to 200 simple eyes around the edge of its mantle. How many eyes do scallops have? Scallops can have up to 200 eyes.
The cheetah is the fastest land animal, capable of reaching speeds of up to 120 km/h (75 mph) over short distances. This incredible speed allows cheetahs to quickly catch their prey, which they then drag to a safe location to feed.
Chameleons are famous for their ability to change color to match their surroundings. This camouflage helps them avoid predators and ambush their prey more effectively.
The box jellyfish is considered the most venomous marine animal. Its tentacles contain a powerful venom that can cause excruciating pain, muscle paralysis, and even death in humans.
The electric eel is capable of generating powerful electric shocks of up to 600 volts. This ability allows the eel to stun prey, defend itself, and navigate its environment.
The millipede has the most legs of any animal, with up to 750 legs.
The glass frog has a transparent body that allows its internal organs to be visible.
The Greenland shark is the longest-living vertebrate, with a lifespan of up to 400 years.
The mayfly has one of the shortest lifespans of any animal, living for only 24 hours as an adult.
The Mexican cave fish is completely eyeless, having evolved to live in the dark caves where it resides.
