Animal Diversity Web

Ge­o­graphic Range

Pygmy killer whales ac­count for less than 1% of odon­to­cete sight­ings (Mc­Sweeney et al, 2008). Al­though pygmy killer whales are rarely seen in the wild, they have been recorded as far north as the Bay of Bis­cay near France (Williams et al., 2002) and as far south as the African cape (Per­rin, 2010). They have been found at nu­mer­ous lo­ca­tions world­wide, be­tween 45˚ north and 35˚ south lat­i­tude; un­for­tu­nately, this species has not been re­li­ably found in any one area (Mc­Sweeney et al., 2008). They are typ­i­cally found in deep (Ward, Mo­scrop, and Carl­son, 2001), warm tem­per­ate, sub-trop­i­cal and trop­i­cal wa­ters all over the globe (Williams et al., 2002). They have been recorded most fre­quently in the tem­per­ate wa­ters of the Pa­cific and south At­lantic Oceans, near the Hawai­ian Is­lands (Mc­Sweeney et al, 2008), in the Gulf of Mex­ico, near Japan, in the In­dian Ocean and in trop­i­cal west­ern Africa (MarineBio, 1998). ("Fer­esa at­ten­u­ata, Pygmy Killer Whale", 1998; Mc­Sweeney, et al., 2008; Per­rin, 2010; Ward, et al., 2001; Williams, et al., 2002)

The fol­low­ing lo­ca­tions have been doc­u­mented for pygmy killer whale sight­ings: the Venezue­lan Caribbean, Puerto Rico, British Vir­gin Is­lands, Trel­lis Bay (Ward, Mo­scrop, and Carl­son, 2001), Florida (Mon­tie, Manire, and Mann, 2011), Brazil, Ar­gentina, South Africa (Zerbini and de Oliveira San­tos, 1997), Cen­tral Eng­lish Chan­nel, Bay of Bis­cay (Williams, Williams, Br­ere­ton, 2002), Mal­di­vian arch­i­pel­ago, south of Sri Lanka (Mad­sen, Kerr, and Payne, 2004), West In­dian area, South At­lantic, Pa­cific Ocean, In­dian Ocean, Peru, Gulf of Mex­ico, west­ern Africa (MarineBio, 1998), and the Hawai­ian Is­lands (Mc­Sweeney et al, 2008). ("Fer­esa at­ten­u­ata, Pygmy Killer Whale", 1998; Mad­sen, et al., 2004; Mc­Sweeney, et al., 2008; Ward, et al., 2001; Williams, et al., 2002; Zerbini and de Oliveira San­tos, 1997)

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

• Other Geographic Terms
• cosmopolitan

Habi­tat

Pygmy killer whales de­pend on their hear­ing for com­mu­ni­ca­tion, hunt­ing, and in­ter­act­ing with the ma­rine world around them (Mon­tie, 2011). Rarely kept cap­tive, they have only been stud­ied dur­ing the few chance ob­ser­va­tions in the wild (IUCN Red List of Threat­ened Species, 2009). While nor­mally oc­cu­py­ing warm, deep wa­ters, pygmy killer whales have been spot­ted near shal­lower oceanic is­lands as well (Ward, Mo­scrop, and Carl­son, 2001). A 21 year study in the Hawai­ian Is­lands fo­cused on whales at depths up to 500 me­ters; lit­tle is known about pygmy killer whales at depths greater than 500 me­ters, al­though they have been recorded at depths greater than 2500 me­ters (Mc­Sweeney et al, 2008). ("IUCN Red List of Threat­ened Species", 2009; Mc­Sweeney, et al., 2008; Mon­tie, 2011; Ward, et al., 2001)

• Habitat Regions
• temperate
• tropical
• saltwater or marine

• Aquatic Biomes
• pelagic
• coastal

• Range depth

  113 to 2,862 m

  370.73 to ft

• Average depth

  1,218 m

  ft

Phys­i­cal De­scrip­tion

Pygmy killer whales were first doc­u­mented in 1827 by J. Gray, using a skull. Gray gave them an al­ter­nate name. Pygmy killer whales were sub­se­quently doc­u­mented again in 1874 by Gray, at which time he called them Fer­esa at­ten­u­ata. From 1960 to the pre­sent, the name Fer­esa at­ten­u­ata has been the rec­og­nized name (Zerbini and de Oliveira San­tos, 1997).

On av­er­age, pygmy killer whales weigh 150 kg and are 2.3 me­ters in length (Mad­sen, Kerr, and Payne, 2004; Williams et al., 2002; MarineBio, 1998; IUCN Red List of Threat­ened Species, 2009). Pygmy killer whales are eas­ily misiden­ti­fied as ei­ther ju­ve­nile false killer whales or melon-headed whales (Mc­Sweeney et al, 2008). Some of the dis­tin­guish­able fea­tures of Fer­esa at­ten­u­ata in­clude: a dark gray-black stout body, sig­nif­i­cantly lighter un­der­belly, blunt head with­out a beak, and an under slung jaw which usu­ally con­tains a whitish color set of lips. The dor­sal fin is nearly cen­tered on the body and the flip­pers have rounded tips and are of mod­er­ate length. The dor­sal fin it­self is one of the best ways to dis­tin­guish this mam­mal from other cetaceans; it reaches high off the dor­sal back, lacks rigid­ity, points slightly back­ward, and has a sub-tri­an­gu­lar shape. An­other phys­i­cal char­ac­ter­is­tic is an ex­tend­ing groove on the pygmy killer whale's skin, from just ahead of the um­bili­cus to the anus. This fea­ture holds the gen­i­tals, anus, and um­bili­cus in both sexes (En­cy­clo­pe­dia of Life, 2003); how­ever the pres­ence of a ven­tral, post-anal keel could be a def­i­nite dis­tinc­tion be­tween males and fe­males (Mc­Sweeney et al, 2008).

The bone struc­ture of pygmy killer whales is fairly dis­tinc­tive; not only is the mandible hol­low, but the left side is larger and usu­ally con­tains one more tooth than the right. This dif­fer­ence in size makes the skull asym­met­ri­cal, com­mon in many odoto­cete whales. The lower jaw holds be­tween 11 and 13 large, con­i­cal pairs of teeth while the upper usu­ally holds 8 to 11. Off the Brazil­ian coast, sci­en­tists recorded mea­sure­ments of a stranded fe­male, not­ing that phys­i­cal ma­tu­rity in this species is most likely reached when the ver­te­bral epi­phy­ses and cen­tra in all ver­te­brae are fused. Also use­ful in dis­tin­guish­ing ma­ture pygmy killer whales from ju­ve­niles is that each tooth's pulp cav­ity is filled and that os­si­fied cra­nial su­tures occur in adults (Zerbini and de Oliveira San­tos, 1997). The dis­tance be­tween the end of the tooth row and the ante-or­bital notch is an­other dis­tinc­tive char­ac­ter­is­tic used in iden­ti­fy­ing a pygmy killer whale that was stranded in the Delta of Parnaíba River, Brazil (De Ma­g­a­l­haes et al, 2007). ("Fer­esa at­ten­u­ata Gray, 1874", 2003; "Fer­esa at­ten­u­ata, Pygmy Killer Whale", 1998; "IUCN Red List of Threat­ened Species", 2009; De Ma­g­a­l­haes, et al., 2007; Mad­sen, et al., 2004; Mc­Sweeney, et al., 2008; Williams, et al., 2002; Zerbini and de Oliveira San­tos, 1997)

• Other Physical Features
• endothermic
• homoiothermic
• bilateral symmetry

• Sexual Dimorphism
• sexes alike

• Range mass

  110 to 170 kg

  242.29 to 374.45 lb

• Average mass

  150 kg

  330.40 lb

• Range length

  2.1 to 2.6 m

  6.89 to 8.53 ft

• Average length

  2.3 m

  7.55 ft

Re­pro­duc­tion

Pygmy killer whale mat­ing be­hav­iors are not re­ported in the lit­er­a­ture.

Al­though there is very lit­tle data on the mat­ing sys­tem of the pygmy killer whale, sci­en­tists be­lieve that at lengths greater than 2.16 me­ters, males be­come sex­u­ally ma­ture, and at lengths greater than 2.21 me­ters fe­males be­come sex­u­ally ma­ture (MarineBio, 1998).

Un­for­tu­nately ges­ta­tion pe­riod, mat­ing habits, and parental care, are un­known for this species. Other del­phinids of sim­i­lar size birth in the sum­mer months, usu­ally pro­duc­ing one calf (MarineBio, 1998). Pygmy killer whale calves mea­sure roughly 0.8 me­ters (32 inches) at birth (Ward et al., 2001). One calf is born with each preg­nancy. ("Fer­esa at­ten­u­ata, Pygmy Killer Whale", 1998; Ward, et al., 2001)

• Key Reproductive Features
• iteroparous
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• viviparous

• Average number of offspring

  1

Al­though it is fairly easy to dis­tin­guish nurs­ing, fe­male Fer­esa at­ten­u­ata from males and ju­ve­niles, there are no stud­ies about parental in­vest­ment in this species. Gen­er­ally, in a pod of newly born calves, adults near­est to the calves are the moth­ers, while other adults with­out calves are most often males. Be­sides view­ing the adult fe­males near the calves, there is lit­tle re­search about how long the moth­ers care for their young, or if the males help at all. Like most whales, young pygmy killer whales are born able to swim on their own (Mc­Sweeney et al, 2008). (Mc­Sweeney, et al., 2008)

• Parental Investment
• precocial
• female parental care
• pre-fertilization
  • provisioning
  • protecting
    • female
• pre-hatching/birth
  • provisioning
    • female
  • protecting
    • female
• pre-weaning/fledging
  • provisioning
    • female
  • protecting
    • female

Lifes­pan/Longevity

Lit­tle is known about longevity of pygmy killer whales. In a study in the Hawai­ian Is­lands that lasted over 21 years, sci­en­tists iden­ti­fied at least one in­di­vid­ual pygmy killer whale through­out the en­tire study (Mc­Sweeney et al, 2008). (Mc­Sweeney, et al., 2008)

• Range lifespan
  Status: wild

  21 (high) years

Be­hav­ior

This species is so­cial, hav­ing been seen in pods rang­ing from 4 to 50 in­di­vid­u­als. Oc­ca­sional groups of up to sev­eral hun­dred in­di­vid­u­als have been ob­served (Ward et al., 2001). They have been spot­ted beat­ing their flukes and flip­pers on the top of the water, growl­ing, and even snap­ping their jaws ag­gres­sively. Even in cap­tiv­ity these crea­tures have been known to show de­fen­sive re­ac­tions to­wards other cetaceans and their train­ers (MarineBio, 1998).

Pygmy killer whales have been doc­u­mented on sev­eral oc­ca­sions as being slow swim­ming del­phinids. Some sight­ings have noted that they are play­ful and ac­ro­batic (En­cy­clo­pe­dia of Life, 2003) while oth­ers re­gard their move­ments as slow and non-ac­ro­batic (Williams et al., 2002). Sev­eral cat­e­gories have been used to clas­sify be­hav­iors of pygmy killer whales while mov­ing in the water. Dur­ing the 21 year study off the main Hawai­ian Is­lands, Mc­Sweeney et al. (2008) de­scribed these group be­hav­iors as travel, slow travel, milling, so­cial, log­ging, and/or rest­ing. Each was used de­pend­ing on the speed of the an­i­mal, in­ter­ac­tion with po­ten­tial prey, di­rec­tion of move­ment, or lo­ca­tion within the water and other in­di­vid­u­als. They may be mainly ac­tive at night, when they are thought to feed. They have been spot­ted on nu­mer­ous oc­ca­sions swim­ming slowly at a dis­tance of at least 50 me­ters from ships (Williams et al., 2002) . ("Fer­esa at­ten­u­ata Gray, 1874", 2003; "Fer­esa at­ten­u­ata, Pygmy Killer Whale", 1998; Mad­sen, et al., 2004; Mc­Sweeney, et al., 2008; Ward, et al., 2001; Williams, et al., 2002)

• Key Behaviors
• natatorial
• nocturnal
• motile
• nomadic
• sedentary
• social
• colonial

Home Range

This species is thought to be non-mi­gra­tory based on year-round ob­ser­va­tions of in­di­vid­u­als in areas such as the Lesser An­tilles (Ward et al., 2001). ("Fer­esa at­ten­u­ata Gray, 1874", 2003; Mc­Sweeney, et al., 2008; Ward, et al., 2001)

Com­mu­ni­ca­tion and Per­cep­tion

Pygmy killer whales make click­ing and whistling sounds sim­i­lar to bot­tlenose dol­phins and can growl through their blow­holes (En­cy­clo­pe­dia of Life, 2003). Like other dol­phins, they use echolo­ca­tion to nav­i­gate their en­vi­ron­ment. A study done in the In­dian Ocean recorded a peak range be­tween 45 and 117 kHz (kilo­hertz) made through these bi­modal clicks; the clicks them­selves were short, di­rec­tional broad­band sig­nals with in­ten­sity lev­els rang­ing from 197 to 223 dB (deci­bels). Both fre­quency and in­ten­sity were higher than false killer whales.

Anatom­i­cal stud­ies done on 2 stranded pygmy killer whales off a Florida beach in 2008 pro­vided in­sight into sound per­cep­tion. Acoustic vi­bra­tions travel through blub­ber in hol­low jaw­bones. This blub­ber presses against the tym­panope­ri­otic com­plex, trans­mit­ting the sound to the mid­dle and inner ear. There are two re­gions of the brain, the me­dial genic­u­late body and in­fe­rior col­licu­lus, as well as the au­di­tory nerve, that re­cieve and in­ter­pret acoustic sig­nals (Mon­tie, 2011). Sci­en­tists were able to doc­u­ment that pygmy killer whales per­ceived fre­quen­cies at 40 kHz best. The low­est au­di­ble thresh­old was about 20 kHz whereas the high­est was 120 kHz (Mon­tie, 2011). ("Fer­esa at­ten­u­ata Gray, 1874", 2003; Mad­sen, et al., 2004; Mon­tie, 2011; Mon­tie, et al., 2011)

• Communication Channels
• tactile
• acoustic

• Perception Channels
• visual
• tactile
• acoustic
• chemical

Food Habits

Lit­tle is known about the diet of this species. How­ever, based on stom­ach con­tents of sev­eral stranded spec­i­mens, pygmy killer whales have been known to con­sume cephalopods (Williams et al., 2002), large fish, oc­to­pus, squid, (MarineBio, 1998), and smaller cetaceans (Mad­sen et al., 2004). Sci­en­tists be­lieve that these whales feed in deep wa­ters at night (Mc­Sweeney et al, 2008). ("Fer­esa at­ten­u­ata, Pygmy Killer Whale", 1998; Mad­sen, et al., 2004; Mc­Sweeney, et al., 2008; Williams, et al., 2002)

• Primary Diet
• carnivore
  • piscivore
  • molluscivore

• Animal Foods
• mammals
• fish
• mollusks
• aquatic crustaceans
• other marine invertebrates

Pre­da­tion

Pygmy killer whales are ag­gres­sive and don't have many nat­ural preda­tors. Some po­ten­tial preda­tors in­clude orcas, large sharks, and hu­mans (En­cy­clo­pe­dia of Life, 2003). ("Fer­esa at­ten­u­ata Gray, 1874", 2003)

• Known Predators

  • humans (Homo sapiens)

Ecosys­tem Roles

Pygmy killer whales prey on fish, mol­lusks, and small cetaceans. Lit­tle re­search has been done to de­ter­mine the po­ten­tial par­a­sites or dis­eases of Fer­esa at­ten­u­ata, al­though they are known to har­bor ne­ma­tode par­a­sites, Anisakis sim­plex (Zerbini and de Oliveira San­tos , 1997) (Mad­sen, et al., 2004; Zerbini and de Oliveira San­tos, 1997)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

There are no known pos­i­tive im­pacts of pygmy killer whales on hu­mans.

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

Pgymy killer whales have no neg­a­tive im­pact on hu­mans. (Mc­Sweeney, et al., 2008)

Con­ser­va­tion Sta­tus

Some of the po­ten­tial threats to this species in­clude fish­ing and har­vest­ing (in­ten­tion­ally killing for sub­sis­tence by hu­mans or ac­ci­den­tal mor­tal­ity from by­catches), pol­lu­tion, such as solid waste and garbage, noise pol­lu­tion from sonar, and cli­mate change that can alter habi­tat (IUCN Red List of Threat­ened Species, 2009). Al­though it is not known for cer­tain, the thy­roid sys­tem of the pygmy killer whale (much like other ma­rine species) could be neg­a­tively af­fected by some man-made pol­lu­tants (Mon­tie, 2011). Stud­ies show that es­ti­mated pop­u­la­tion sizes of pygmy killer whales are 817 in Hawai­ian wa­ters, 408 in the north­ern Gulf of Mex­ico, and 38,900 in the trop­i­cal Pa­cific (IUCN Red List of Threat­ened Species, 2009). ("IUCN Red List of Threat­ened Species", 2009; Mon­tie, 2011)

• IUCN Red List

  Data Deficient
  More information

• IUCN Red List

  Data Deficient
  More information

• US Federal List

  No special status

• CITES

  Appendix II

• State of Michigan List

  No special status

Con­trib­u­tors

Tabitha Star­jn­ski (au­thor), Uni­ver­sity of Wis­con­sin-Stevens Point, Christo­pher Yahnke (ed­i­tor), Uni­ver­sity of Wis­con­sin-Stevens Point, Tanya Dewey (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor.

Ref­er­ences

2003. "Fer­esa at­ten­u­ata Gray, 1874" (On-line). En­cy­clo­pe­dia of Life. Ac­cessed Au­gust 20, 2011 at http://​www.​eol.​org/​pages/​328531.

1998. "Fer­esa at­ten­u­ata, Pygmy Killer Whale" (On-line). MarineBio. Ac­cessed Au­gust 15, 2011 at http://​marinebio.​org/​species.​asp?​id=356.

2009. "IUCN Red List of Threat­ened Species" (On-line). In­ter­na­tional Union for Con­ser­va­tion of Na­ture and Nat­ural Re­sources (IUCN). Ac­cessed Au­gust 19, 2011 at http://​www.​iucnredlist.​org/​apps/​redlist/​details/​8551/​0.

De Ma­g­a­l­haes, F., R. Garri, C. Tosi, S. Si­cil­iano, S. Chel­lappa, F. De Llima Silva. 2007. First con­firmed record of Fer­esa at­ten­u­ata (Del­phinidae) for the North­ern Brazil­ian Coast. Biota Neotrop­ica, 7(2): 313-318. Ac­cessed Au­gust 25, 2011 at http://​www.​biotaneotropica.​org.​br/​v7n2/​en/​fullpaper?​bn03507022007+en.

Kiszka, J., K. Macleod, O. Van Can­neyt, D. Walker, V. Ri­doux. 2007. Dis­tri­b­u­tion, en­counter rates, and habi­tat char­ac­ter­is­tics of toothed cetaceans in the Bay of Bis­cay and ad­ja­cent water from plat­form-of-op­por­tu­nity data. ICES Jour­nal of Ma­rine Sci­ence, 64(5): 1033-10433. Ac­cessed Au­gust 23, 2011 at http://​icesjms.​oxfordjournals.​org/​content/​64/​5/​1033.​full.

Mad­sen, P., I. Kerr, R. Payne. 2004. Source pa­ra­me­ter es­ti­mates of echolo­ca­tion clicks from wild pygmy killer whales (Fer­esa at­ten­u­ata) (L). Acousti­cal So­ci­ety of Amer­ica, 116(4): 1909-1912. Ac­cessed Au­gust 12, 2011 at http://​marinebioacoustics.​com/​files/​2004/​Madsen_​et_​al_​2004a.​pdf.

Mc­Sweeney, D., R. Baird, S. Ma­haffy, D. Web­ster, G. Schorr. 2008. Site fi­delity and as­so­ci­a­tion pat­terns of a rare species: Pygmy killer whales (Fer­esa at­ten­u­ata) in the main Hawai­ian Is­lands. Ma­rine Mam­mal Sci­ence, 25(3): 557-572. Ac­cessed Au­gust 12, 2011 at http://​onlinelibrary.​wiley.​com.​ezproxy.​uwsp.​edu/​doi/​10.​1111/​j.​1748-7692.​2008.​00267.​x/​full.

Mon­tie, E. 2011. How pygmy killer whales hear. The Jour­nal of Ex­per­i­men­tal Bi­ol­ogy, 214.i: 1-3. Ac­cessed Au­gust 17, 2011 at http://​jeb.​biologists.​org/​content/​214/​6/​i.​1.​full.​pdf+html.

Mon­tie, E., C. Manire, D. Mann. 2011. Live CT imag­ing of sound re­cep­tion anatomy and hear­ing mea­sure­ments in the pygmy killer whale, Fer­esa at­ten­u­ata. The Jour­nal of Ex­per­i­men­tal Bi­ol­ogy, 214: 945-955.

Per­rin, W. 2010. "Fer­esa at­ten­u­ata Gray, 1874" (On-line). World Reg­is­ter of Ma­rine Species. Ac­cessed Au­gust 21, 2011 at http://​www.​marinespecies.​org/​aphia.​php?​p=taxdetails&​id=137095.

Ward, D., A. Mo­scrop, D. Carl­son. 2001. El­e­ments for the de­vel­op­ment of a ma­rine mam­mal ac­tion plan for the wider Caribbean: a re­view of ma­rine mam­mal dis­tri­b­u­tion. First Meet­ing of the Con­tract­ing Par­ties (COP) to the Pro­to­col Con­cern­ing Spe­cially Pro­tected Areas and Wildlife (SPAW) in the Wider Caribbean Re­gion: 1-77. Ac­cessed Au­gust 13, 2011 at http://​www.​cep.​unep.​org/​pubs/​meetingreports/​SPAW%20COP/​English%20Docs/​IG20-inf3en.​doc.

Williams, A., R. Williams, T. Br­ere­ton. 2002. The sight­ing of pygmy killer whales (Fer­esa at­ten­u­ata) in the south­ern Bay of Bis­cay and their as­so­ci­a­tion with cetacean calves. Jour­nal of the Ma­rine Bi­o­log­i­cal As­so­ci­a­tion of the United King­dom, 82(3): 509-511. Ac­cessed Au­gust 12, 2011 at http://​www.​marine-life.​org.​uk/​media/​24585/​williams_​2002_​pygmy%20killer%20whale_​jmba.​pdf.

Zerbini, A., M. de Oliveira San­tos. 1997. First record of the pygmy killer whale Fer­esa at­ten­u­ata (Gray, 1874) for the Brazil­ian coast. Aquatic Mam­mals, 23.2: 105-109. Ac­cessed Au­gust 15, 2011 at http://​www.​aquaticmammalsjournal.​org/​share/​AquaticMammalsIssueArchives/​1997/​AquaticMammals_​23-02/​23-02_​Zerbini.​pdf.