Animal Diversity Web

Ge­o­graphic Range

Manta rays are found in trop­i­cal and warm tem­per­ate coastal re­gions of the world's oceans, gen­er­ally be­tween 35 de­grees north and south lat­i­tude, in­clud­ing the coasts of south­ern Africa, rang­ing from south­ern Cal­i­for­nia to north­ern Peru, North Car­olina to south­ern Brazil, and the Gulf of Mex­ico. (Bigelow and Schroeder, 1954; Fish­Base, 1999; Ocean­Link, 1997)

• Biogeographic Regions
• indian ocean
  • native
• atlantic ocean
  • native
• pacific ocean
  • native

Habi­tat

Manta birostris, un­like most other rays, are found near the sur­face of the ocean and to depths of 120 me­ters. At­lantic manta rays stay closer to shore in the warmer wa­ters where food sources are more abun­dant, but oc­ca­sion­ally can be found fur­ther from shore. (Acker (MRBH), 2001; Bigelow and Schroeder, 1954)

• Habitat Regions
• tropical
• saltwater or marine

• Aquatic Biomes
• pelagic
• reef
• coastal

• Range depth

  0 to 120 m

  0.00 to 393.70 ft

Phys­i­cal De­scrip­tion

Manta rays are eas­ily re­conized in the ocean by their large pec­toral "wings." Manta birostris have no cau­dal fins and a small dor­sal fin. They have two cephalic lobes that ex­tend from the front of the head and a broad, rec­tan­gu­lar, ter­mi­nal mouth con­tain­ing small teeth ex­clu­sively in the lower jaw. The gills are lo­cated on the un­der­side of the body. Manta rays also have a short, whip-like tail that, un­like many rays, has no sharp barb. At­lantic manta ray pups weigh 11 kg at birth and their growth is rapid, with pups vir­tu­ally dou­bling the body width from birth through the first year of life. Manta rays show lit­tle di­mor­phism be­tween the sexes with wingspan in males rang­ing from 5.2 - 6.1 me­ters and fe­males rang­ing from 5.5 - 6.8 me­ters. The largest ever recorded was 9.1 me­ters. One of the dis­tinct fea­tures of manta rays, and of the class Chon­drichthyes, is that the en­tire skele­ton is made of car­ti­lage, which al­lows for a wide range of mo­tion. These rays vary in color from black to gray­ish blue along the back, and a white un­der­side with gray­ish blotchs that have been used to iden­tify in­di­vid­ual rays. The skin of manta rays is rough and scaly, like that of most sharks. ("Manta Rays", 1989; Acker (MRBH), 2001; Bigelow and Schroeder, 1954)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry

• Sexual Dimorphism
• female larger

• Range mass

  1200 to 1400 kg

  2643.17 to 3083.70 lb

Re­pro­duc­tion

Manta birostris are sex­u­ally ma­ture at 5 years of age. The mat­ing sea­son of sex­u­ally ma­ture manta rays oc­curs from early De­cem­ber to late April. Mat­ing takes place in trop­i­cal wa­ters (26-29 de­grees Cel­sius), and around rocky reef areas from 10-20 me­ters in depth. Manta rays gather in large num­bers dur­ing this sea­son, where sev­eral males will court a sin­gle fe­male. The males swim closely be­hind the tail of the fe­male at faster than usual speeds (9-12km/h). This courtship will last for about 20-30 min­utes at which point the fe­male de­creases her swim­ming speed and a male will grasp one side of the fe­male's pec­toral fin by bit­ing it. He arranges his body under that of the fe­males. The male will then in­sert his clasper in the cloaca of the fe­male and in­sert his sperm, this usu­ally last­ing around 90-120 sec­onds. The male will then swim away rapidly and the next male will re­peat this same process. How­ever, after the sec­ond male the fe­male usu­ally swims away leav­ing be­hind the other court­ing males. The ges­ta­tion pe­riod of Manta birostris is 13 months, after which fe­males give birth to 1 or 2 live young. Pups are born wrapped up by their pec­toral fins, but soon after be­come free swim­mers and fend for their­selves. Manta ray pups are be­tween 1.1 and 1.4 me­ters when they are born. (Acker (MRBH), 2001; Yano, et al., 1999)

• Key Reproductive Features
• iteroparous
• seasonal breeding
• sexual
• fertilization
  • internal
• viviparous

• Average age at sexual or reproductive maturity (female)
  Sex: female

  2190 days

  AnAge

Lifes­pan/Longevity

• Average lifespan
  Status: captivity

  20 years

  AnAge

Be­hav­ior

Manta rays are soli­tary, free swim­mers who are not ter­ri­to­r­ial. Manta birostris use their flex­i­ble pec­toral fins to swim grace­fully through the ocean. At­lantic manta rays are most ac­tive dur­ing the mat­ing sea­son, and have been recorded leap­ing out of the water to heights of 7 feet, then smack­ing against the sur­face. By doing this, man­tas may re­move ir­ri­tat­ing par­a­sites and dead skin on their large bod­ies. Also, Manta birostris have been seen at "clean­ing sta­tions" with wrasse fish swim­ming about them pick­ing off par­a­sites and dead skin. An­other sym­bi­otic in­ter­ac­tion that man­tas have is with remora fish, which at­tach to the giant man­tas and hitch rides with them while feed­ing on the man­tas par­a­sites and on plank­ton. Manta rays have no par­tic­u­lar anti-preda­tor spe­cial­iza­tions other than their tough skin, but due to their size they do not have many nat­ural preda­tors. Large sharks have been known to at­tack manta rays. ("Manta Rays", 1989; Bigelow and Schroeder, 1954; Dive Asia, 2004)

• Key Behaviors
• natatorial
• motile
• migratory
• solitary

Food Habits

Manta rays are fil­ter feed­ers and pri­mar­ily plank­ti­vores. They often slowly swim in ver­ti­cal loops. Some re­searchers sug­gest this is done to keep the rays prey within the area while feed­ing. Their large, gap­ing mouths and cephalic lobes un­furled are used to cor­ral plank­tonic crus­taceans and small school­ing fish. Manta rays fil­ter water through their gills and or­gan­isms in the water are trapped by a fil­ter­ing de­vice, which con­sists of plates in the back of the mouth that are made of pink­ish-brown tis­sue that span be­tween the sup­port struc­tures of the gills. The teeth of Manta birostris are non­func­tional dur­ing feed­ing. ("Manta Rays", 1992; Dive Asia, 2004; Perl­mut­ter, 1961)

• Primary Diet
• carnivore
  • eats non-insect arthropods

• Animal Foods
• fish
• aquatic crustaceans
• zooplankton

• Foraging Behavior
• filter-feeding

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

In the past, Manta birostris was com­mer­cially hunted from small boats. Cur­rently this species is rarely hunted. The biggest im­pact that the manta ray cur­rently has comes from tourism, with dive in­dus­tries being cre­ated for tourists who want to swim along side these gen­tle gi­ants. In­quis­i­tive man­tas will ap­proach and even so­licit at­ten­tion from divers, ap­par­ently en­joy­ing the stim­u­la­tion pro­vided by human con­tact and the bub­bles from scuba ex­haust. Al­though, it has been recorded that manta rays that fre­quently en­counter hu­mans will shy away from con­tact with hu­mans. ("Manta Rays", 1992; Colla (ocean­light) and Mar­tin, 1998; Mc­Cormick, et al., 1963)

• Positive Impacts
• ecotourism

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Manta birostris have no ad­verse af­fects on hu­mans.

Con­ser­va­tion Sta­tus

Pop­u­la­tion sizes of Manta birostris are un­known. Be­cause of their slow re­pro­duc­tive rate, they are very vul­ner­a­ble to over­fish­ing. How­ever, there does not ap­pear to be com­mer­cial har­vest­ing at this time. The IUCN lists this species as "Data De­fi­cient," mean­ing they don't have enough in­for­ma­tion to as­sess its con­ser­va­tion sta­tus.

• IUCN Red List

  No special status
  More information

• IUCN Red List

  No special status
  More information

• US Federal List

  No special status

• CITES

  No special status

Other Com­ments

The av­er­age life span of Manta birostris is 18-20 years. The At­lantic manta ray was once thought to be ag­gres­sive and harm­ful to hu­mans as sailors cre­ated myths about them. The com­mon myth was that man­tas could cap­size ones boat by leap­ing out of the water and crash­ing down upon it. An­other com­mon mis­con­cep­tion is that man­tas drown swim­mers by wrap­ping around them. They are called "devil" ray be­cause of the cephalic fins at the front of their heads, which re­sem­ble the horns of a devil. Also fish­ing boats re­ported that At­lantic manta rays would cir­cle about their boats for long pe­ri­ods of time. These man­tas were prob­a­bly just dis­play­ing their cor­ralling be­hav­ior dur­ing feed­ing.

In the past, two other species of manta, known as the "lesser" devil rays, Manta birostris (Pa­cific manta ray) and Manta al­fredi (Prince Al­fred's manta ray) were con­sid­ered sep­a­rate from Manta birostris. They have since been rec­og­nized as the same species, all now called M. birostris.

The name of manta is de­rived from the Span­ish word, mean­ing blan­ket. (Bigelow and Schroeder, 1954; Mc­Cormick, et al., 1963)

Con­trib­u­tors

George Ham­mond (ed­i­tor), An­i­mal Di­ver­sity Web.

Gre­gory Shu­ral­eff II (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Phil Myers (ed­i­tor), Mu­seum of Zo­ol­ogy, Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

1992. Manta Rays. Pp. 1512-1514 in En­cy­clo­pe­dia of the An­i­mal, vol. 8 (Ott-Rhe). New York: Boy Books.

1989. Manta Rays. Pp. 582-583 in Wildlife of the World En­cy­clo­pe­dia, vol. 10 (Rav-Slo). New York: Cavendish Pub­lish­ing.

Acker (MRBH), B. 2001. "Manta facts" (On-line). Manta Ray Bay Hotel and Yap Divers. Ac­cessed 11/01/04 at http://​www.​mantaray.​com.

Bigelow, H., W. Schroeder. 1954. Fishes of the West­ern North At­lantic. Copen­hagen: Yale Uni­ver­sity.

Colla (ocean­light), P., R. Mar­tin. 1998. "Giant Pa­cific Manta Ray Pho­tos/On the Bi­ol­ogy of the Manta Ray" (On-line). Phillip Colla Pho­tog­ra­phy. Ac­cessed 11/01/04 at http://​www.​oceanlight.​com/​html/​manta_​birostris.​html.

Dive Asia, 2004. "Dive Asia Reef Ecol­ogy Guide- Car­ti­lagi­nous Fishes" (On-line). Dive Asia, Div­ing in Phuket, Thai­land and Burma. Ac­cessed 11/01/04 at http://​www.​diveasia.​com/​reef-guide/​cartilaginous.​htm.

Fish­Base, 1999. "Manta birostris" (On-line). FishBase.​org. Ac­cessed March 7, 2000 at http://​www.​fishbase.​org/​Seach.​cfm.

Mc­Cormick, H., T. Allen, W. Young. 1963. Shad­ows of the Sea. Philadel­phia: Chilton Com­pany.

Ocean­Link, 1997. "Ocean Link An­swers to Chon­drichthyes Ques­tions" (On-line). Ocean­Link. Ac­cessed 11/01/04 at http://​oceanlink.​island.​net/​ask/​chondrichthyes.​html#​anchor139401.

Perl­mut­ter, A. 1961. Guide to Ma­rine Fishes. New York: New York Uni­ver­sity Press.

Yano, K., F. Sato, T. Tomoko. 1999. Ob­ser­va­tions of mat­ing be­hav­ior of the manta ray, Manta birostris, at the Oga­sawara Is­lands, Japan. Ichthy­olog­i­cal Re­search, 46: 289-296.