Do you think you can swim faster than a penguin? You might be in for a surprise. The penguin is actually the best swimmer of all birds. It can reach speeds of 50 km/h underwater, using its wings as fins to propel itself along and its tail to steer.
A sea otter can reach speeds of 10 km/h, and a walrus, 15 km/h. The sea tortoise, despite its name, can swim at speeds of 35 km/h, while dolphins and whales can move along at nearly 65 km/h.
Few animals can outrace sharks and swordfish. They are the speediest of all ocean dwellers, attaining speeds of about 65 km/h.
An Olympic swimming champion can reach 5 km/h. Can you swim that fast? In other words, you wouldn't have much chance in a race against the marine animals described above. What about other animals? Do you know how fast they can swim?