It is common knowledge that we have five senses. Some people believe they have six senses. They say their sixth sense is the ability to know something without using the ordinary five senses of sight, hearing, smell, touch and taste. Scientists have just discovered that some dolphins have seven senses. Researchers in Germany say bottlenose dolphins can sense electricity produced by their prey. The dolphins can detect the electric pulses produced by the heart beats of other sea creatures. This could help dolphins to find their next meal. Dolphins also use their excellent eyesight and sonar to sense what is around them. This seventh sense may also help them to navigate using Earth's magnetic field.

The researchers conducted a study on two dolphins named Dolly and Donna. Experiments tested what kinds of electricity the dolphins could detect. Dolly and Donna could sense both kinds of electricity – direct current and alternating current. They were a lot better at picking up direct current. All organisms produce direct current electricity in water. The researchers say being able to detect this means dolphins may be able to sense the location of most kinds of fish that are near them. The dolphins could use their seventh sense to hunt, even if they cannot see or hear well, or if they cannot use their other senses. The study has been published in the "Journal of Experimental Biology".