
Crab Facts: Claws, Shells & Secret Behaviors
Crabs are crustaceans found on every continent with over 7,000 species. Discover why crabs walk sideways, trade shells, and grow claws stronger than jaws.

Dolphins are highly intelligent marine mammals known for complex communication, social bonds, and problem solving. They use echolocation to navigate and hunt underwater.
Dolphins have signature whistles that function as names. Each dolphin creates a unique whistle pattern in their first months of life, and other dolphins remember these whistles for over 20 years.
Dolphins cannot breathe unconsciously like humans. They must consciously surface for air, creating a problem when they need sleep. Dolphins are never fully unconscious.
Dolphin brains have a higher brain to body ratio than any mammal except humans. They recognize themselves in mirrors, demonstrating self awareness found only in great apes, elephants, and magpies. Wild dolphins use tools, carrying marine sponges on their beaks to protect themselves while foraging on rough seafloor.
Dolphin echolocation produces 1,000 clicks per second, with returning echoes creating detailed mental images. This biological sonar is so precise dolphins distinguish between different fish species and detect coin sized objects hundreds of feet away. They can even perceive the internal structure of objects.
Dolphins live in fission fusion societies where pod membership constantly changes. Some dolphins form lifelong friendships lasting decades. Males create coalitions of 2 to 3 individuals that cooperate to access females.
Newborn dolphin calves and their mothers do not sleep for the entire first month after birth. They remain constantly active and alert, swimming continuously. This happens because calves lack the blubber needed for buoyancy and would sink if they stopped swimming.
Fishing nets kill thousands of dolphins annually through bycatch. The vaquita porpoise numbers fewer than 10 individuals, functionally extinct. Maui dolphins have fewer than 100 left.
Dolphins sleep with one brain hemisphere at a time so they never lose consciousness
Each dolphin has a unique signature whistle that functions as its name
They can remember other dolphins' signature whistles for over 20 years
Dolphin brains are larger than human brains relative to body size
They use echolocation clicks up to 1,000 times per second for navigation
Dolphins recognize themselves in mirrors showing self awareness
Dolphins are among the most intelligent animals with brain to body ratios second only to humans. They show self awareness, use tools, solve complex problems, understand symbolic communication, and transmit cultural knowledge. Their cognitive abilities rival great apes.
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