Denmark has twice as many pigs as there are people.
66
The elephant brain weighs about 6,000g.
274
Rattlesnake mating sessions have been known to last more than 22 hours.
232
Blue whale arteries are large enough for humans to swim through and their hearts are the size of cars.
12
Cats are one of the only animals to domesticate themselves and approach humans on their own terms.
20