Editing Blue whale (section)

===Predators===
The only known natural predator to blue whales is the [[orca]], although the rate of fatal attacks by orcas is unknown. Photograph-identification studies of blue whales have estimated that a high proportion of the individuals in the [[Gulf of California]] have rake-like scars, indicative of encounters with orcas.<ref name=Sears_1990>{{cite journal | author1=Sears, R. | title=The Cortez blues | journal=Whalewatcher | volume=24 | pages=12–15 | date=1990}}</ref> Off southeastern [[Australia]], 3.7% of blue whales photographed had rake marks and 42.1% of photographed pygmy blue whales off Western Australia had rake marks.<ref name=Mehta_etal_2007>{{cite journal | author1=Mehta, A. V. | author2=Allen, J. M. | author3=Constantine, R. | author4=Garrigue, C. | author5=Jann, B. | author6=Jenner, C. | author7=Marx, M. K. | author8=Matkin, C. O. | author9=Mattila, D. K. | author10=Minton, G. | author11=Mizroch, S. A. | author12=Olavarría, C. | author13=Robbins, J. | author14=Russell, K. G. | author15=Seton, R. E. | title=Baleen whales are not important as prey for orcas (''Orcinus orca'') in high latitudes | journal=Marine Ecology Progress Series | volume=348 | pages=297–307 | date=2007| doi=10.3354/meps07015 | doi-access=free | hdl=1912/4520 | hdl-access=free }}</ref> Documented [[predation]] by orcas has been rare. A blue whale mother and calf were first observed being chased at high speeds by orcas off southeastern Australia.<ref name=Cotton_1944>{{cite journal | author1=Cotton, B. C. | title=Killer whales in South Australia | journal=[[Australian Zoologist]] | volume=10 | pages=293–294 | date=1944}}</ref> The first documented attack occurred in 1977 off southwestern [[Baja California, Mexico]], but the injured whale escaped after five hours.<ref name=Tarpy_1979>{{cite journal | author1=Tarpy, C. | title=Killer whale attack! | journal=National Geographic Magazine | volume=155 | pages=542–545| date=1979}}</ref> Four more blue whales were documented as being chased by a group of orcas between 1982 and 2003.<ref name=Ford_Reeves_2008>{{cite journal | author1=Ford, J. K. B. | author2=Reeves, R. | title=Fight or flight: antipredator strategies of baleen whales | journal=[[Mammal Review]] | volume=38 | issue=1 | pages=50–86 | date=2008| doi=10.1111/j.1365-2907.2008.00118.x }}</ref> The first documented predation event by orcas occurred in September 2003, when a group of orcas in the [[Eastern Tropical Pacific]] was encountered feeding on a recently killed blue whale calf.<ref name=Pitman_etal_2007>{{cite journal | author1=Pitman, R. | author2=Fearnbach, H. | author3=LeDuc, R. | author4=Gilpatrick, J. W. | author5=Ford, J. K. B. | author6=Balance, L. T. | title=Killer whales preying on a blue whale calf on the Costa Rica Dome: Genetics, morphometrics, vocalizations and composition of the group | journal=Journal of Cetacean Research and Management | volume=9 | pages=151–158 | date=2023| issue=2 | doi=10.47536/jcrm.v9i2.683 | s2cid=257138804 | doi-access=free }}</ref> In March 2014, a commercial whale watch boat operator recorded an incident involving a group of orcas harassing a blue whale in [[Monterey Bay]]. The blue whale defended itself by slapping its tail.<ref>{{cite web | url=https://www.livescience.com/43879-killer-whales-attack-blue-whale-video.html | title=Killer Whales Bully Lone Blue Whale in Rare Video | date=5 March 2014 | publisher=[[Live Science]] | access-date=23 December 2019}}</ref> A similar incident was recorded by a drone in Monterey Bay in May 2017.<ref>{{cite web | url=https://www.nationalgeographic.com/news/2017/05/killer-whale-attacks-blue-whale-monterey-drone-video | archive-url=https://web.archive.org/web/20191231040658/https://www.nationalgeographic.com/news/2017/05/killer-whale-attacks-blue-whale-monterey-drone-video/ | url-status=dead | archive-date=31 December 2019 | title=Killer Whales Attacked a Blue Whale—Here's the Surprising Reason Why | date=25 May 2017 | publisher=National Geographic | access-date=23 December 2019}}</ref> The first direct observations of orca predation occurred off the south coast of Western Australia, two in 2019 and one more in 2021. The first victim was estimated to be {{convert|18|–|22|m|sp=us}}.<ref>{{cite journal|author1=Totterdell, J. A.|author2=Wellard, R.|author3=Reeves, I. M.|author4=Elsdon, B.|author5=Markovic, P.|author6=Yoshida, M.|author7=Fairchild, A.|author8=Sharp, G.|author9=Pitman, R.|year=2022|title=The first three records of killer whales (''Orcinus orca'') killing and eating blue whales (''Balaenoptera musculus'')|journal=Marine Mammal Science|volume=38 |issue=3 |pages=1286–1301 |doi=10.1111/mms.12906|bibcode=2022MMamS..38.1286T | s2cid=246167673 }}</ref>