This is used as a defense mechanism and also to immobilize prey. These generate an electric current, which varies from 8 volts up to 220 volts. Some stingrays have more than one stinger.Įlectric rays are a different shape to stingrays with a stubby tail and extended, flat pectoral fins containing a pair of kidney-shaped organs. Depending on the species, the stinger can be up to 35 centimetres long and has grooves that contain venom glands. They hide under wrecks, inside caverns or on the reef and only ever sting in self-defense. Stingrays have a barbed stinger, and despite the negative publicity at times, these rays tend to be placid creatures that avoid contact with others.
You are more likely to see spine-tailed devil rays in groups.Anyone who dives will probably already know that rays are related to sharks – although they look nothing like them – and that rays drop loosely into two groups, those that sting in some way (electric and sting rays) and those that don't, such as mobula and manta rays.
Behaviour – Oceanic manta rays are generally solitary (besides for courtship, mating and aggregating at feeding sites or cleaning stations). Depending on the concentration of food, these rays may feed in a straight line or barrel roll (somersault) through the water column.Ĩ. Diet – Both oceanic manta rays and spine-tailed devil rays feed on plankton such as krill, copepods and crustacean larvae. Analysis of collection records and sightings data suggest that spine-tailed devil rays are more abundant than oceanic manta rays in New Zealand.ħ. Population Size – Global population size estimates for both species are lacking as well as population size estimates for New Zealand.
In New Zealand, they are usually found in waters deeper than 200m in the open ocean. The oceanic manta rays are generally found along the continental shelf in water temperatures of 18☌ or more.Ħ. Range – The spine-tailed devil ray is found worldwide in tropical to warm, temperate waters. This ray feeds on plankton and small fish and are completely harmless to humans. What is the largest ray What is the largest skate The giant manta ray (Manta birostris) is the largest ray reaching up to 9 meters in width. Stingers – Whilst both are closely related to stingrays, the oceanic manta ray does not have a stinger at the end of its tail whereas the spine-tailed devil ray does. Another difference is that rays are generally much larger than skates. The mouth of the manta ray is at the front of its head, whereas stingrays have their mouths under. Appearance – Besides their difference in size, there are some differences in appearance which can help us tell the two apart.Ĥ. Appearance: Manta rays have eyes on the side of their heads, whilst stingrays have eyes on top of their body. Length – A fully grown oceanic manta ray’s wingspan can reach up to 7m whilst spine-tailed devil rays reach to about 2m.ģ. Size – Adult oceanic manta rays weigh up to 2,000kg whereas the spine-tailed devil rays reach about 300kg in weight.Ģ. We’ve written this species spotlight in conjunction with Manta Watch New Zealand, to raise awareness of their research about these majestic creatures.ġ. These impressive rays are often confused with spine-tailed devil rays. Current knowledge of oceanic manta rays in New Zealand is very limited.
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