The Basenji dog is the only dog that is not able to bark.
4
Sheep, goats, octopuses, and toads have rectangular pupils.
7
A hippo sleeping underwater automatically rises to the surface every ~4 minutes and breathes without waking.
23
A domestic cat can sprint at about 31 miles per hour.
274
Parrotfish make themselves a kind of mucus 'sleeping bag' which masks their smell from predators and keeps parasites away.
4