As far as is known, they are immune to every known disease including cancer. Snails produce a colorless, sticky discharge that forms a protective carpet under them as they travel along. The discharge is so effective that they can crawl along the edge of a razor without cutting themselves. Snakes are immune to their own poison. Some baby giraffes are more than six feet tall at birth.
Swans are the only birds with penises.
Tapeworms range in size from about 0.04 inch to more than 50 feet in length. The 1st buffalo ever born in captivity was born at Chicago's Lincoln Park Zoo in 1884. The anaconda, one of the world's largest snakes, gives birth to its young instead of laying eggs. The animal responsible for the most human deaths world-wide is the mosquito. The average adult male ostrich, the world's largest living bird, weighs up to 345 pounds.