Are Manta Rays Dangerous? Stingers, Size and Safe Diving

Do manta rays have a stinger?

No. Manta rays belong to the same order as stingrays and evolved from bottom-living stingrays, but they lost the venomous barb along the way. The giant manta ray still has a small knob or spine near the base of its tail, a leftover of that barb, but it has no venom and plays no role in defense. The reef manta lacks even this.

This is the biggest difference from stingrays such as the southern stingray, which carry one or more sharp, serrated, venomous spines on the tail. A stingray uses its barb in self-defense when it is stepped on or grabbed, as explained in are stingrays dangerous? A manta has nothing comparable.

Can a manta ray bite you?

Mantas are not known to bite people. Their teeth are tiny and set in bands in the lower jaw, and they play no part in feeding. A manta eats by swimming with its huge mouth open, while filter plates between its gill arches trap plankton. During courtship, males use their teeth to hold on to the tip of a female’s fin, which leaves scars on females but has nothing to do with people.

Even a manta’s open mouth, which can look alarming in photos, is harmless. The prey that mantas eat is mostly smaller than a fingernail: krill, copepods, shrimp and fish larvae, plus small fish.

Why were manta rays feared?

Mantas once had a frightening reputation. Their horn-like cephalic fins earned them the name devilfish, and their great size made them seem powerful and menacing. Sailors told stories of mantas dragging boats out to sea by the anchor line or wrapping their wings around divers to drown them. None of these stories has any basis in fact.

The image changed in the 1970s, when divers in the Gulf of California found that mantas were calm and tolerated people close by. Since then, mantas have become famous for their gentleness and curiosity. Some individuals approach divers repeatedly, apparently investigating them or the bubbles from their scuba gear.

Are there any real risks around manta rays?

The risks are small and mostly come from the ocean itself. Mantas gather at places with strong currents, upwelling and plankton-rich water, so manta dives can be physically demanding, and boats are often nearby. A giant manta weighs more than a tonne, and an accidental bump from a wing could knock a swimmer, but mantas are agile and usually avoid contact.

Some rays leap clear of the water and land with a crash, as described in why do manta rays jump? Boats should slow down where rays are jumping, both to avoid hitting them and because a large ray landing in a small boat could hurt someone.

The animal more likely to cause an injury at a manta site is a stingray resting in the sand of a shallow beach or lagoon. Shuffling your feet when wading in such places warns stingrays to move away, a habit explained in what is the stingray shuffle? If anyone is stung, seek emergency medical help immediately: call 911 in the US, 112 in the EU or 999 in the UK.

How to swim with manta rays responsibly

Manta watching is a major tourist activity in places such as Hawaii, Mexico, the Maldives, Indonesia, Thailand and Mozambique. Guidelines used by many dive operators and manta researchers include:

• Keep a distance of at least about 3 m (10 ft), and let the manta decide how close to come.
• Never touch, ride or grab a manta, and do not chase it or block its path.
• Approach slowly from the side, not head-on or from directly above.
• At cleaning stations, where mantas hover while small fish clean them, stay low and to the side and do not swim over the station.
• Snorkelers should stay at the surface rather than diving down on top of mantas.
• Follow local rules on the number of swimmers and on lights or flash photography.

At the famous night manta dives off the Kona coast of Hawaii, for example, divers stay on the seabed or at the surface and shine lights into the water. Plankton gathers in the light, and reef mantas glide and somersault through it to feed, often passing very close to the divers without touching them.

Are people dangerous to manta rays?

Yes, far more than mantas are to people. The giant oceanic manta is listed as Endangered by the IUCN, and the reef manta as Vulnerable. Their populations have fallen because of fishing, both for their gill plates, which are sold dried in parts of Asia, and as bycatch in nets and longlines. Mantas also get tangled in fishing line and mooring ropes, are struck by boats, and swallow microplastics while feeding.

Even well-meaning tourists can cause harm. Touching a manta can rub off the layer of mucus that protects its skin from infection, and crowds of swimmers can drive mantas away from the cleaning stations and feeding areas they depend on. Respectful tourism, on the other hand, helps mantas: a living manta can bring local communities far more money over its lifetime than a dead one, which has encouraged countries such as Indonesia and Ecuador to protect them.

Mantas and stingrays are close relatives, but they differ in many ways besides the stinger; see manta ray vs stingray for a side-by-side comparison.