Zoology
Kangaroos essentially cannot walk backwards
Their thick tail and huge hind feet make reversing impractical — one reason the kangaroo appears on Australia's coat of arms as a symbol of moving forward.
More in Zoology
A shrimp can shoot a bubble hotter than lava
The pistol shrimp snaps its claw so fast it creates a collapsing cavitation bubble, producing a shockwave, a flash of light and a crack loud enough to stun prey.
Sperm whales sleep standing up in the water
They drift vertically in short naps of around ten to fifteen minutes, motionless like floating pillars, holding their breath the whole time.
Cows have best friends
Studies show cows pair up with preferred companions, and their heart rate and stress hormones rise when separated from that particular friend.
Sea otters hold hands while they sleep
Floating in rafts, otters grip each other — or wrap themselves in kelp — so the current does not carry them apart during the night.
A snow leopard's tail is almost as long as its body
It works as a counterweight for leaps across cliffs, and wraps around the animal like a scarf against Himalayan cold.
The pangolin is the only mammal covered in scales
Its armour is keratin — the same material as your fingernails — and it rolls into a ball so tight that even lions usually give up.