The elephant brain weighs about 6,000g.
274
Roosters can't crow if they can't fully extend their necks.
28
Eagles mate while airborne.
44
Some species of fish have voices!
81
There are no penguins in the North Pole.
56
Blue whale arteries are large enough for humans to swim through and their hearts are the size of cars.
12
Tigers can see 6 times better at night than humans.
305
