We have five senses. Some people may have six. A sixth sense could be knowing something without using the senses of sight, hearing, smell, touch and taste. Researchers have found that some dolphins have seven senses. Dolphins can sense electricity from the heart beats of sea creatures. This could help dolphins to find food. It could also help them to navigate by using electricity from Earth's magnetic field.

Researchers tested what kinds of electricity dolphins could sense. They sensed two kinds. They were better at sensing direct current electricity. All sea creatures produce this. Being able to sense this helps dolphins to know how near other fish are to them. Dolphins could use this to hunt, even if they cannot see or hear well. Sometimes the water is cloudy, so they cannot use their other senses.