Dolphins Can See Electricity

The Guiana dolphin possesses the astounding ability to orgasm while spurting out a generous 50 to 100 mL dose of semen in just a bat of an eye, and of course they’ve got echolocation. But in addition to those traits, researchers have now discovered one more accessory in the clever cetaceans’ toolkit: electroreceptors.

With the keen knack to spot electrical vibrations, the dolphins can sense the electric fields of their prey and use it to uncover various objects within their vicinity such as mackerel, herring or the occasional codfish. It’s the very first time the ability has been discovered amongst true mammals, which are those that evolved during the Triassic period.

According to a recent paper, scientists explored the anatomy in a dead dolphin and also guided a live one to interact with an electric field identical to that created by a fish. In the past, it was hypothesized that the animals might have electroreceptors as evidenced by the dark pits, called vibrissal crypts, found on their snouts. Ancestral dolphins had whiskers emerging from these pits, which would increase their sensitivity and suggest that they indeed have been receptors. But in present-day dolphins the pits were considered trivial, partially because they no longer have whiskers.

However, infrared photographs taken during the study revealed the crypts "lighting up with activity," proving to researchers that the crypts are put to use. The team used tissue samples of the deceased dolphin's beak, and examined the cellular structure of the crypts which uncovered no indication of hair particles or whiskers. Instead, a gel-like substance was discovered in its cells. It is a similar liquid to that found in the receptors of electrical fish that helps produce frequency cues, and ultimately confirms that dolphins have electro-sensory ability.

Electroreception is rare, but occurs in a few mammals. The echidna, a spiny anteater residing in Australia and New Guinea, has electroreceptors in his snout. The amazing critter, just for reference, also has a four-headed penis.

While some humans might drool at the prospect of gaining electrosensory ability, it seems we might have already had it. Scientists think that all original animals with backbones, including early ancestors of humans, could sense electricity. As they developed, mammals, reptiles, birds and the majority of fish lost the the ability, probably because they didn’t much need it. Today, only sharks and a few other seagoing species can sense electricity. However, it seems that some remnant of the trait has been left behind: the same genes that help regulate the development of electroreceptors in sharks have been implicated in the development of the head and facial features in humans.

-Kimberly Haddad