It’s hard to see from the water’s surface, but adult orcas are, on average, about as long as a small school bus (19 to 26 feet long) and they can weigh up to six tons.
When they are asleep, one part of their brain remains alert and awake. This keeps them safe from potential predators, and enables them to breathe while sleeping.
The blue whale's heart is huge. It's the largest heart in the animal kingdom, weighing about 400 pounds (180 kg) and roughly the size of a bumper car.
The vertebrae in a beluga’s neck is not fused together, giving it the unusual ability to turn its head up, down and side-to-side.
Male humpback whales are famous for singing songs to the females they are courting. These songs are distinctly different within each breeding stock.
Seahorses have no teeth and no stomach. Food passes through their digestive systems so quickly, they must eat almost constantly to stay alive.